389 results on '"Nitrilimine"'
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2. Sequential, Electrochemical‐Photochemical Synthesis of 1,2,4‐Triazolo‐[4,3‐a]pyrazines.
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Yount, Joseph, Morris, Megan, Henson, Noah, Zeller, Matthias, Byrd, Edward F. C., and Piercey, Davin G.
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PYRAZINES , *ULTRAVIOLET lamps , *TETRAZOLES , *RING formation (Chemistry) , *SPINE - Abstract
1,2,4‐triazolo‐[4,3‐a]pyrazine was prepared via a two‐step electrochemical, photochemical process. First, a 5‐substituted tetrazole is electrochemically coupled to 2,6‐dimethoxypyrazine to yield 1,5‐ and 2,5‐ disubstituted tetrazoles. Subsequent photochemical excitation of the 2,5‐disubstituted tetrazole species using an ultraviolet lamp releases nitrogen gas and produces a short‐lived nitrilimine intermediate. Subsequent cyclization of the nitrilimine intermediate yields a 1,2,4‐triazolo‐[4,3‐a]pyrazine backbone. The scope of this reaction was explored using various tetrazoles and pyrazines. Materials produced were identified using chemical analytical techniques and computationally studied for potential application as an insensitive energetic material. [ABSTRACT FROM AUTHOR]
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- 2024
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3. On the Mechanism of the Synthesis of Nitrofunctionalised Δ2-Pyrazolines via [3+2] Cycloaddition Reactions between α-EWG-Activated Nitroethenes and Nitrylimine TAC Systems
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Agnieszka Fryźlewicz, Aleksandra Olszewska, Karolina Zawadzińska, Przemysław Woliński, Karolina Kula, Agnieszka Kącka-Zych, Agnieszka Łapczuk-Krygier, and Radomir Jasiński
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[3+2] cycloaddition ,nitrilimine ,nitroalkene ,Δ2-pyrazoline ,molecular electron density theory (MEDT) ,Organic chemistry ,QD241-441 - Abstract
We investigated the reactivity of different substituted nitrylimine-type three atom components (TACs) in [3+2] cycloaddition (32CAs) reactions with electrophilically activated nitroethenes within molecular electron density theory (MEDT). In parallel research, the molecular mechanism of the considered transformation was examined through analysis of all possible reaction channels and full optimization of all critical structures. In particular, the existence of zwitterionic intermediates on reaction paths was verified. On the basis of the bonding evolution theory (BET), the mechanism of the 32CA reaction between C,N-diphenylnitrylimine and (E)-2-phenyl-1-cyano-1-nitroethene should be treated as a one-step two-stage mechanism.
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- 2022
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4. Exploration of the mechanism, chemospecificity, regiospecificity and stereoselectivity of the cycloaddition reaction between 9α-hydroxyparthenolide and nitrilimine: MEDT study.
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Ouahdi, Zenab, Ourhriss, Najia, Aitouna, Anas Ouald, Barhoumi, Ali, Belghiti, Mohammed Elalaoui, Moubarik, Amine, El Alaoui El Abdallaoui, Habib, El Idrissi, Mohammed, and Zeroual, Abdellah
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RING formation (Chemistry) , *CHEMOSELECTIVITY , *STEREOSELECTIVE reactions , *ELECTRON density , *DOUBLE bonds , *ACTIVATION energy - Abstract
The 32CA cycloaddition reactions of the hydroxyparthenolide with nitrilimine have been studied using molecular electron density theory. The reactivity indices, activation and reaction energies are calculated at the B3LYP/6-31(d) level. The presence of two double bonds in hydroxyparthenolide gives six reaction pathways for this cycloaddition. The reaction proceeds via a one-step asynchronous mechanism with a nonpolar character, and an analysis of conceptual DFT indices explains the nonpolar character of this cycloaddition reaction. The calculations of the activation and reaction energies show that this cyclization reaction takes place on the C1=C2 double bond, which indicates that this cycloaddition reaction is chemospecific and regiospecific in full conformity with the experimental results. The reorganization of electrons along the most preferred pathway of the 32CA cycloaddition reaction between hydroxyparthenolide and nitrilimine was investigated using topological analysis of the electron localization function (ELF). ELF analysis revealed that this reaction proceeds through a two-stage one-step mechanism. [ABSTRACT FROM AUTHOR]
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- 2022
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5. On the Mechanism of the Synthesis of Nitrofunctionalised Δ²-Pyrazolines via [3+2] Cycloaddition Reactions between α-EWG-Activated Nitroethenes and Nitrylimine TAC Systems.
- Author
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Fryźlewicz, Agnieszka, Olszewska, Aleksandra, Zawadzińska, Karolina, Wolińsk, Przemysław, Kula, Karolina, Kącka-Zych, Agnieszka, Łapczuk-Krygier, Agnieszka, and Jasiński, Radomir
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ELECTRON distribution , *INTERMOLECULAR forces , *PEPTIDES , *RING formation (Chemistry) , *HYDROGEN bonding - Abstract
We investigated the reactivity of different substituted nitrylimine-type three atom components (TACs) in [3+2] cycloaddition (32CAs) reactions with electrophilically activated nitroethenes within molecular electron density theory (MEDT). In parallel research, the molecular mechanism of the considered transformation was examined through analysis of all possible reaction channels and full optimization of all critical structures. In particular, the existence of zwitterionic intermediates on reaction paths was verified. On the basis of the bonding evolution theory (BET), the mechanism of the 32CA reaction between C,N-diphenylnitrylimine and (E)-2-phenyl-1-cyano-1-nitroethene should be treated as a one-step two-stage mechanism. [ABSTRACT FROM AUTHOR]
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- 2022
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6. An Isolable Gallium‐Substituted Nitrilimine and its Reactivity with B−H, Si−H and B−B Bonds.
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Kassymbek, Aishabibi, Gusev, Dmitry G., Dmitrienko, Anton, Pilkington, Melanie, and Nikonov, Georgii I.
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DIAZO compounds , *DIBORANE , *BORANES , *MOIETIES (Chemistry) - Abstract
Reaction of the Ga(I) compound NacNacGa (9) with the diazo compound N2CHSiMe3 affords the nitrilimine compound NacNacGa(N‐NCSiMe3)(CH2SiMe3) (10). Carrying out this reaction in the presence of pyridine does not lead to C−H activation on the transient alkylidene NacNacGa=CHSiMe3 but generates a metallated diazo species NacNacGa(NHN=CHSiMe3)(CN2SiMe3) (13) that further rearranges into the isonitrile compound NacNacGa(NHN=CHSiMe3)(N(NC)SiMe3) (15). Reactions of 10 with the silane H3SiPh and the borane HBcat furnished products of 1,3 addition to the nitrilimine moiety NacNacGa{N(ERn)NCSiMe3}(CH2SiMe3), whereas reaction with the diborane B2cat2 gave the product of formal nitrene insertion into the B−B bond. DFT calculations suggest that the interaction of 9 with N2CHSiMe3 proceeds through intermediate formation of an alkylidene compound that undergoes CH activation with a second molecule of N2CHSiMe3. Insertion into the B−B bond likely proceeds through an initial 1,3‐addition of the diborane, followed by boryl migration to the former nitrene center. [ABSTRACT FROM AUTHOR]
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- 2022
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7. [3+2] Cycloaddition reactions of 1-substituted 3,3,3-trifluoropropenes with diazo compounds and nitrilimines – synthesis of pyrazolines and pyrazoles.
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Маrkitanov, Yuriy N., Тimoshenko, Vadim М., Мykhaylychenko, Sergiy S., Rusanov, Eduard B., Khyzhan, Alexandr I., and Shermolovich, Yuriy G.
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RING formation (Chemistry) , *NITRILIMINES , *PYRAZOLES , *DIAZOMETHANE , *SULFAMIDE , *DIAZO compounds - Abstract
1,3-Dipolar cycloaddition reactions of 3,3,3-trifluoropropene derivatives containing a sulfonyl, sulfamide, or sulfoximine substituent in position 1 with diazomethane proceed with the formation of 3-substituted 4-(trifluoromethyl)-4,5-dihydro-1H-pyrazoles and 3-(trifluoromethyl)-1H-pyrazole, whereas reactions with ethyl diazoacetate and 2,2,2-trifluorodiazoethane lead to the formation of isomeric 5(3)-substituted 4-trifluoromethyl-3,4(4,5)-dihydro-2(1)H-pyrazoles and 4-substituted 5-(trifluoromethyl)-4,5-dihydro-1Hpyrazoles, the stability of which depends on the nature of the heteroatomic substituent. The cycloaddition of 1-sulfonyl- and 1-sulfamoylsubstituted derivatives of 3,3,3-trifluoropropene to C-carbethoxy-N-phenylnitrilimine gives rise to 4-substituted ethyl 1-phenyl-5-(trifluoromethyl)-4,5-dihydro-1H-pyrazole-3-carboxylates and ethyl 1-phenyl-4-(trifluoromethyl)-1H-pyrazole-3-carboxylate. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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8. Dual 1,3-dipolar cycloaddition of nitrilimines with cyclopenta[a]acenaphthylen-8-ones. A synthesis of hexacyclic bis-dihydropyrazoles.
- Author
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Yavari, Issa, Ravaghi, Parisa, and Safaei, Maryam
- Abstract
A regioselective 1,3-dipolar cycloaddition of nitrilimines, generated from hydrazonoyl chlorides, with both C = C double bonds of cyclopentadienone moiety of cyclopenta[a]acenaphthylen-8-ones in the presence of Et
3 N is described. This dual cycloaddition reaction affords a nearly 3:2 mixture of symmetrical and unsymmetrical hexacyclic bis-dihydropyrazol derivatives in good yields. The stereochemistry of diethyl 3,7-bis(4-chlorophenyl)-4-oxo-1,5-diphenyl-1H-naphtho[1′,8′:4,5,6]pentaleno[1,6a-c:3a,3-c′]dipyrazole-3a,4a(4H,5H)-dicarboxylate was established by X-ray crystallography. [ABSTRACT FROM AUTHOR]- Published
- 2020
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9. Synthesis of Novel 1-(1,5-Diaryl-1,10b-Dihydropyrrolo- [1,2-A][1,2,4]Triazolo[3,4-C]Pyrazin-3-Yl)Ethanones Via 1,3-Dipolar Cycloaddition of Nitrilimine.
- Author
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Huang, Yulin, Ren, Demin, Yu, Xianyong, Zeng, Ju-Lan, and Li, Xiaofang
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RING formation (Chemistry) , *PYRAZINES , *ISOXAZOLIDINES , *BROMIDES - Abstract
The 1,3-dipolar cycloaddition of nitrilimine, generated in situ from (Z)-N-aryl-2-oxopropanehydrazonoyl bromide and Et3N, to 3-arylpyrrolo[ 1,2-a]pyrazine afforded novel 1-(1,5-diaryl-1,10b-dihydropyrrolo[1,2-a][1,2,4]triazolo[3,4-c]pyrazin-3-yl)ethanones in moderate yields. The structures of all the products were characterized thoroughly by NMR, IR, and HRMS. [ABSTRACT FROM AUTHOR]
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- 2020
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10. Design, synthesis and characterization of functionalized pyrazole derivatives bearing amide and sulfonamide moieties from aza-aurones.
- Author
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Chalkha, Mohammed, Bakhouch, Mohamed, Akhazzane, Mohamed, Bourass, Mohamed, Nicolas, Yohann, Al Houari, Ghali, and El Yazidi, Mohamed
- Abstract
In this work, we report the synthesis of new pyrazole derivatives bearing amide and sulfonamide frameworks from aza-aurones. Firstly, the intermediate spiropyrazolines were obtained through a highly regioselective 1,3-dipolar cycloaddition of nitrilimines with aza-aurones. Subsequently, the obtained cycloadducts were subjected to hydrochloric acid in hot ethanol which conducts to 5-(2-aminobenzoyl)-3,4-diaryl-1-phenylpyrazoles. Finally, the target compounds were obtained separately by the action of acetic anhydride, benzoyl chloride and tosyl chloride on the intermediates 2-aminobenzoylpyrazoles, respectively. Structures of all the synthesized compounds were established using IR, 1H NMR and 13C NMR and mass spectroscopy. Synthesis and characterization of novel heterocyclic systems encompassing pyrazole derivatives from aza-aurones are reported. The synthetic routes used in this work are efficient and relevant, involving the 1,3-dipolar cycloaddition and alkylation reactions. The outcomes show that spectroscopic data fit the structure of all synthesized compounds. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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11. Photoinduced Porcine Gelatin Cross-Linking by Homobi- and Homotrifunctional Tetrazoles
- Author
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Luca Vaghi, Mauro Monti, Marcello Marelli, Elisa Motto, Antonio Papagni, and Laura Cipolla
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gelatin ,hydrogel ,photochemistry ,tetrazoles ,nitrilimine ,chemical cross-linking ,Science ,Chemistry ,QD1-999 ,Inorganic chemistry ,QD146-197 ,General. Including alchemy ,QD1-65 - Abstract
Gelatin is a costless polypeptide material of natural origin, able to form hydrogels that are potentially useful in biomaterial scaffold design for drug delivery, cell cultures, and tissue engineering. However, gelatin hydrogels are unstable at physiological conditions, losing their features only after a few minutes at 37 °C. Accordingly, treatments to address this issue are of great interest. In the present work, we propose for the first time the use of bi- and trifunctional tetrazoles, most of them unknown to date, for photoinduced gelatin cross-linking towards the production of physiologically stable hydrogels. Indeed, after UV-B irradiation, aryl tetrazoles generate a nitrilimine intermediate that is reactive towards different functionalities, some of them constitutively present in the amino acid side chains of gelatin. The efficacy of the treatment strictly depends on the structure of the cross-linking agent used, and substantial improved stability was observed by switching from bifunctional to trifunctional cross-linkers.
- Published
- 2021
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12. 1,3-Dipolar cycloaddition of diphenylnitrilimine and 5-arylmethylidene-1-phenyl-1,5,6,7-tetrahydro-4H-indazol-4-ones to afford novel spiro[indazole-5,3′-pyrazole] derivatives.
- Author
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Ren, Demin, Kuang, Guoqiang, and Li, Xiaofang
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RING formation (Chemistry) , *NITRILIMINES , *METHYLIDENES , *CHEMICAL derivatives , *ORGANIC synthesis - Abstract
Novel 4'-aryl-1,2',5'-triphenyl-2',4',6,7-tetrahydrospiro[indazole-5,3'-pyrazol]-4(1H)-ones have been synthesized in moderate yields by 1,3-dipolar cycloaddition of 5-arylmethylidene-1-phenyl-1,5,6,7-tetrahydro-4H-indazol-4-ones and diphenylnitrilimine, generated in situ from N-phenylbenzohydrazonoyl chloride and triethylamine. According to structural analyses by NMR spectroscopy and single crystal X-ray diffraction method, the reaction proceeds regioselectively affording products with C(5)-C(3') connectivity at the spiro center. [ABSTRACT FROM AUTHOR]
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- 2018
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13. DFT study of double 1,3-dipolar cycloaddition of nitrilimines with allenoates.
- Author
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Soleymani, Mousa
- Abstract
Abstract: The double 1,3-dipolar cycloaddition reaction between nitrilimine and allenoate, experimentally investigated by Guo and co-workers, was theoretically studied at the B3LYP/6-311G** and wB97XD/6-311G** computational levels in both gas phase and dichloromethane solution. The results indicated that the formation of the experimentally reported product is clearly explained by the analysis of the calculated Fukui function reactivity indices as well as transition states studies. Frontier molecular orbitals analysis showed that the HOMO orbital of nitrilimine as donor is also the frontier effective-for-reaction molecular orbital (FERMO). Finally, on the basis of the Wiberg bond indexes and AIM analysis, it was found that all of the reactive channels proceed through an asynchronous concerted mechanism.Graphical abstract: [ABSTRACT FROM AUTHOR]
- Published
- 2018
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14. Theoretical Study of Reaction Between Nitrilimine and 1,4 oxazine 2 Carboxylate by MP2 and DFT Methods.
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EL HADKI, H., HLIMI, F., SALAH, M., MARAKCHI, K., KOMIHA, N., and KABBAJ, O. K.
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CARBOXYLATES ,NITRILIMINES ,OXAZINES ,TRANSITION state theory (Chemistry) ,POTENTIAL energy - Abstract
The regioselectivity of the reaction between phenyldiazen-1-ium-1-ylidene p-tolyl methanide and ethyl 4-benzoyl-4H-benzo[1,4]oxazine-2-carboxylate were studied by means of the DFT/B3LYP method coupled by the 6-31g(d) basis and MP2 in connection with 6-31G(d) and 6-31G+(d,p) basis set. The mechanism of this regioselectif reaction has performed by transition state optimization, evaluation of the potential energy surface, calculation of IRC and reactivity indices. Location and verification of minima and transition structures have been realized by using the Berny's algorithm. The process of formation of the two regioisomers is achieved through concerted and asynchronous mechanism. The results are in good agreement with the experimental data. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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15. Thermally Activable Bistetrazoles for Elastomers Crosslinking
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Monti, M, Giannini, L, Tadiello, L, Guerra, S, Papagni, A, Vaghi, L, Monti, Mauro, Giannini, Luca, Tadiello, Luciano, Guerra, Silvia, Papagni, Antonio, Vaghi, Luca, Monti, M, Giannini, L, Tadiello, L, Guerra, S, Papagni, A, Vaghi, L, Monti, Mauro, Giannini, Luca, Tadiello, Luciano, Guerra, Silvia, Papagni, Antonio, and Vaghi, Luca
- Abstract
Sulfur vulcanization is the most used method for curing of natural and synthetic rubbers. The crosslinking degree achieved is usually controlled by adding proper quantities of accelerants, activators, co-activators, retardants, and inhibitors, and influences the hardness, elasticity, hysteresis of elastomers and, consequently, the properties and behavior of the materials that incorporate them. Despite the fine tuning pursued over the years, sulfur crosslinking is still difficult to control both in terms of degree and homogeneity of cross-link. Addition of thermally activable bifunctional reagents able to crosslink the polymer matrix through covalent bonds could be a strategy to modulate and control finely the reticulation grade of elastomers. Tetrazoles can form highly reactive nitrilimines by thermal treatment at appropriate temperature, which can react with the vinyl double bonds present in the rubber. In this work a set of bis-tetrazoles were synthesized and those with the right activation temperatures were used for the curing of styrene-butadiene rubber, acting both as single crosslinkers and together with classic sulfur-based ones. The addition of bistetrazoles simplified and made more efficient the compounding process, allowing to prolong the mixing until optimum dispersion and homogeneity were obtained. Moreover, they led to an improvement in the hysteretic properties of the compound and to the reduction of the non-linearity of the dynamic behavior (Payne effect).
- Published
- 2022
16. Heterocyclic synthesis using nitrilimines: Part 19. Synthesis of novel 1,3,5-trisubstituted-1,2,4-triazoles
- Author
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Hany M.M. Dalloul
- Subjects
Nitrilimine ,1,3-Dipolar cycloaddition ,Guanidine ,1,2,4-Triazoles ,Chemistry ,QD1-999 - Abstract
This paper describes the synthesis of a new series of 1,3,5-trisubstituted-1,2,4-triazoles by 1,3-dipolar cycloaddition reaction of C-phenyl-aminocarbonyl-N-arylnitrilimines with guanidine derivatives. The structures of the newly synthesized compounds were elucidated by spectral methods (IR, 1H NMR, 13C NMR and MS spectroscopy) and elemental analysis. The microbial features of the synthesized compounds were studied using well-established methods from the literature.
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- 2014
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17. Heterocyclic Nitrilimines and Their Use in the Synthesis of Complex High-Nitrogen Materials
- Author
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Ashank Sethia, Sarah E. Davis Finch, Davin G. Piercey, Matthew L. Gettings, Matthias Zeller, and Edward F. C. Byrd
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010405 organic chemistry ,Chemistry ,Nitrilimine ,New materials ,010402 general chemistry ,Mass spectrometry ,01 natural sciences ,0104 chemical sciences ,Inorganic Chemistry ,chemistry.chemical_compound ,Elemental analysis ,High nitrogen ,Organic chemistry ,Tetrazole ,Physical and Theoretical Chemistry - Abstract
We show the ability of a nitrilimine prepared from 3-amino-5-nitro-1,2,4-triazole to undergo various cyclization and rearrangement reactions, giving a beautiful diversity of nitrogen-rich heterocyclic products. This chemistry includes the first cyclization of a nitrilimine with a diazonium species, giving a tetrazole, a previously unknown transformation, as well as leading to the creation of several new energetic materials with backbones not available by traditional techniques. New materials prepared were characterized both chemically (multinuclear NMR, IR, mass spectrometry, and elemental analysis) and energetically, with sensitivities and performances reported.
- Published
- 2021
18. How the Lewis Base F-Catalyzes the 1,3-Dipolar Cycloaddition between Carbon Dioxide and Nitrilimines
- Author
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Kendall N. Houk, Dennis Svatunek, Thomas Hansen, Trevor A. Hamlin, Theoretical Chemistry, Chemistry and Pharmaceutical Sciences, and AIMMS
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010405 organic chemistry ,Nitrilimine ,Organic Chemistry ,Note ,010402 general chemistry ,01 natural sciences ,Medicinal chemistry ,Cycloaddition ,0104 chemical sciences ,Catalysis ,chemistry.chemical_compound ,Medicinal and Biomolecular Chemistry ,chemistry ,Nucleophile ,1,3-Dipolar cycloaddition ,Carbon dioxide ,SDG 13 - Climate Action ,Lewis acids and bases ,SDG 6 - Clean Water and Sanitation - Abstract
The mechanism of the Lewis base F- catalyzed 1,3-dipolar cycloaddition between CO2 and nitrilimines is interrogated using DFT calculations. F- activates the nitrilimine, not CO2 as proposed in the literature, and imparts a significant rate enhancement for the cycloaddition. The origin of this catalysis is in the strength of the primary orbital interactions between the reactants. The Lewis base activated nitrilimine-F- has high-lying filled FMOs. The smaller FMO-LUMO gap promotes a rapid nucleophilic attack and overall cycloaddition with CO2.
- Published
- 2021
19. Nucleophilic Trapping Nitrilimine Generated by Photolysis of Diaryltetrazole in Aqueous Phase
- Author
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Yixin Zhang, Wujun Liu, and Zongbao K. Zhao
- Subjects
photolysis ,tetrazole ,nucleophilic addition ,aqueous-phase reaction ,nitrilimine ,bioorthogonal reaction ,Organic chemistry ,QD241-441 - Abstract
Nitrilimine generated by photolysis of diaryltetrazole in aqueous phase under mild conditions was trapped by nucleophiles including amines and thioalcohols. The representative products were characterized, while products with all 20 natural amino acids and a peptide were observed by MALDI-TOF mass spectroscopy. Competitive studies showed that this reaction also occurred in the presence of acrylamide. These results provided new information for understanding the potential side reactions when tetrazole-alkene pairs were used as a bioorthogonal reaction in labeling proteins and related studies in buffered systems.
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- 2013
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20. The Nitrilimine-Alkene Cycloaddition Regioselectivity Rationalized by Density Functional Theory Reactivity Indices.
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Molteni, Giorgio and Ponti, Alessandro
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ALKENE synthesis , *RING formation (Chemistry) , *REGIOSELECTIVITY (Chemistry) , *NITRILIMINES , *DENSITY functional theory , *REACTIVITY (Chemistry) - Abstract
Conventional frontier molecular orbital theory is not able to satisfactorily explain the regioselectivity outcome of the nitrilimine-alkene cycloaddition. We considered that conceptual density functional theory (DFT) could be an effective theoretical framework to rationalize the regioselectivity of the title reaction. Several nitrilimine-alkene cycloadditions were analyzed, for which we could find regioselectivity data in the literature. We computed DFT reactivity indices at the B3LYP/6-311G(2d,p)//B3LYP/6-31G(d,p) and employed the grand potential stabilization criterion to calculate the preferred regioisomer. Experimental and calculated regioselectivity agree in the vast majority of cases. It was concluded that predominance of a single regioisomer can be obtained by maximizing (i) the chemical potential difference between nitrilimine and alkene and (ii) the local softness difference between the reactive atomic sites within each reactant. Such maximization can be achieved by carefully selecting the substituents on both reactants. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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21. Synthesis of Novel 1-(1,5-Diaryl-1,10b-Dihydropyrrolo- [1,2-A][1,2,4]Triazolo[3,4-C]Pyrazin-3-Yl)Ethanones Via 1,3-Dipolar Cycloaddition of Nitrilimine
- Author
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Ju-Lan Zeng, Xianyong Yu, Xiaofang Li, Yulin Huang, and Demin Ren
- Subjects
chemistry.chemical_compound ,chemistry ,Pyrazine ,010405 organic chemistry ,Bromide ,Nitrilimine ,Organic Chemistry ,1,3-Dipolar cycloaddition ,010402 general chemistry ,01 natural sciences ,Medicinal chemistry ,Cycloaddition ,0104 chemical sciences - Abstract
The 1,3-dipolar cycloaddition of nitrilimine, generated in situ from (Z)-N-aryl-2-oxopropanehydrazonoyl bromide and Et3N, to 3-arylpyrrolo[ 1,2-a]pyrazine afforded novel 1-(1,5-diaryl-1,10b-dihydropyrrolo[1,2-a][1,2,4]triazolo[3,4-c]pyrazin-3-yl)ethanones in moderate yields. The structures of all the products were characterized thoroughly by NMR, IR, and HRMS.
- Published
- 2020
22. Study of Nitrilimines in Cryogenic Matrices: Generation, Characterization and Reactivity by Electronic and Vibrational Excitation
- Author
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Ferreira, Gil Almeida, Nunes, Cláudio Manaia, and Lourenço, Rui Fausto Martins Ribeiro da Silva
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Valence isomerism ,Vibrational Excitation ,Nitrilimina ,Espetroscopia de infravermelho ,Nitrilimine ,Electronic excitation ,Isomerismo de valência ,Excitação eletrónica ,Excitação vibracional ,Infrared spectroscopy - Abstract
Dissertação de Mestrado em Química apresentada à Faculdade de Ciências e Tecnologia The work presented in this master’s thesis focused on the study of nitrile imines by infrared(IR) spectroscopy in cryogenic matrices, with the intent to experimentally identify and characterizedifferent nitrile imine’s bond-shift isomers (a particular case of valence isomers) and assess thepossibility of their interconversion by vibrational excitation with near-infrared irradiation.In this study, we explored the potential energy surfaces of C-(3-hydroxyphenyl) (2) and C-(4-hydroxyphenyl) (2’) nitrile imines using quantum mechanical calculations at B3LYP/6-311++G(d,p) and CBS-QB3 levels of theory, which predicted the existence of allenic andpropargylic bond-shift isomers for nitrile imine 2 and exclusively allenic structures for nitrileimine 2’. Tautomeric and conformational analysis of 5-(3-hydroxyphenyl) (1) and 5-(4-hydroxyphenyl) (1’) tetrazoles at the same level of theory revealed them to be suitable candidatesfor the photochemical generation of nitrile imines 2 and 2’ in cryogenic matrices.5-(3-hydroxyphenyl)-tetrazole 1 was isolated in an argon matrix at 14 K and its mainisomers (2H-tetrazoles 1''-as and 1''-ss) were characterized by IR spectroscopy. Theirphotochemistry was induced by UV irradiation at 230 nm and produced allenic 2A-ss andpropargylic 2P-sa nitrile imines as primary photoproducts. The electronic excitation of thesespecies at 330 nm led to the formation of 1H-diazirine 3-as and its irradiation at 308 nm inducedisomerization to 4-as carbodiimide. The IR spectral characterization of these photoproducts wassupported by harmonic and anharmonic calculations at B3LYP/6-311++G(d,p) and B3LYP/SNSDlevels of theory, respectively. In the near-infrared region, we identified the first NH stretchingovertone bands [2ν(NH)] of species 1''-as/1''-ss, 2A-ss, 2P-sa e 4-as and the first OH stretchingovertone [2ν(NH)] of tetrazole 1. Additionally, the exposure of nitrile imines 2A-ss and 2P-sa tothe broadband infrared radiation emitted by the spectrometer light source (7400 - 50 cm-1) providedspectral evidence which suggest the occurrence of isomerization of allenic 2A-ss to propargylic2P-sa, as a result of vibrational excitation of a non-identified normal mode.The photochemistry of 5-(4-hydroxyphenyl)-tetrazole 1’ isolated in argon matrices at 15 Kwas induced by UV laser irradiation at 230 nm, producing the allenic isomer 2’A-a of C-(4-hydroxyphenyl)-nitrilimine 2’. The electronic excitation of this nitrile imine resulted in theformation of 3’-s diazirine, and the subsequent irradiation at 308 nm induced its isomerization tocarbodiimide 4’-a. Supported by calculations at B3LYP/6-311++G(d,p) and B3LYP/SNSD levels xviof theory, we performed the vibrational characterization of the observed species, the identificationof the 2ν(NH) stretching overtone bands of 1''-a, 2’A-a, 3’-s and 4’-a species and the 2ν(OH)stretching overtone bands of tetrazole 1''-a and nitrile imine 2’A-a.Finally, we began investigating C-(3-aminophenyl) and C-(4-aminophenyl) nitrile iminesby theoretical calculations, which predicted both allenic and propargylic bond-shift isomers for C-(3-aminophenyl)-nitrile imine and only allenic structures for C-(4-aminophenyl)-nitrile imine.Preliminary matrix isolation experiments seem to confirm these theoretical predictions. O trabalho apresentado na presente dissertação centrou-se no estudo de nitriliminas porespetroscopia de infravermelho com isolamento em matrizes criogénicas, com o objetivo deidentificar e caracterizar experimentalmente diferentes isómeros de valência de nitriliminas, eavaliar a possibilidade de fotoisomerização entre eles através de excitação vibracional porirradiação com luz laser na gama do infravermelho próximo.Neste estudo exploraram-se as superfícies de energia potencial das nitriliminas C-(3-hidroxifenil)-nitrilimina 2 e C-(4-hidroxifenil)-nitrilimina 2’ através de cálculos mecânicoquânticos aos níveis B3LYP/6-311++G(d,p) e CBS-QB3, tendo sido previstos isómeros devalência alénicos e propargílicos para a nitrilimina 2 e apenas estruturas de caráter alénico para anitrilimina 2’. Ao mesmo nível de teoria, efetuou-se a análise conformacional e tautomérica dosprecursores 5-(3-hidroxifenil)-tetrazole 1 e 5-(4-hidroxifenil)-tetrazole 1’, que se revelaramcompostos promissores para a geração fotoquímica das nitriliminas 2 e 2’ em matrizes criogénicas.O 5-(3-hidroxifenil)-tetrazole 1 foi isolado numa matriz de árgon a 14 K e os seusprincipais isómeros 1''-as e 1''-ss (2H-tetrazóis) foram caracterizados por espetroscopiavibracional. A fotoquímica destes tetrazóis foi induzida com radiação UV com comprimento deonda de 230 nm e produziu, como fotoprodutos primários, as nitriliminas alénica 2A-ss epropargílica 2P-sa. A excitação eletrónica de 2A-ss e 2P-sa a 330 nm levou formação da 1Hdiazirina 3-as e a irradiação desta a 308 nm resultou na sua isomerização para a carbodiimida4-as. A caracterização por espetroscopia vibracional destes fotoprodutos foi feita com auxílio decálculos computacionais harmónicos ao nível B3LYP/6-311++G(d,p) e anarmónicos ao nívelB3LYP/SNSD. Na região do infravermelho próximo, foram identificadas as bandas do primeirosobretom do modo de elongação NH [2ν(NH)] das espécies 1''-as/1''-ss, 2A-ss, 2P-sa e 4-as e doprimeiro sobretom da elongação OH [2ν(OH)] de 1. Adicionalmente, a exposição de uma matrizcontendo as nitriliminas 2A-ss e 2P-sa à radiação infravermelha de banda larga proveniente dafonte luminosa do espetrómetro (7400 - 50 cm-1) forneceu evidências espetrais que sugerem terinduzido a isomerização da nitrilimina alénicas 2A-ss para isómero de valência propargílico 2Psa, em virtude da excitação vibracional de modos normais de vibração não identificado.A fotoquímica do 5-(4-hidroxifenil)-tetrazole 1’ isolado em matrizes de árgon a 15 K foiinduzida por irradiação UV a 230 nm, produzindo in situ o isómero de caráter alénico 2’A-a da C-xiv(4-hidroxifenil)-nitrilimina 2’. A excitação eletrónica desta nitrilimina resultou na formação dadiazirina 3’-s e a irradiação subsequente a 308 nm induziu a isomerização para a carbodiimida4’-a. Com base em cálculos aos níveis B3LYP/6-311++G(d,p) e B3LYP/SNSD, procedeu-se àcaracterização vibracional das espécies observadas e à identificação das bandas do modo deelongação 2ν(NH) das espécies 1''-a, 2’A-a, 3’-s e 4’-a e do modo de elongação 2ν(OH) dotetrazole 1''-a e da nitrilimina alénica 2’A-a.Por último, iniciou-se o estudo das nitriliminas C-(3-aminofenil)-nitrilimina e C-(4-aminofenil)-nitrilimina através de cálculos teóricos computacionais, que previram isómeros devalência alénicos e propargílicos para a C-(3-aminofenil)-nitrilimina e apenas estruturas alénicaspara a C-(4-aminofenil)-nitrilimina. Os ensaios experimentais preliminares conduzidos parecemsuportar estas previsões teóricas Universidade de Coimbra - POCI-01-0145-FEDER-028973
- Published
- 2022
23. Synthesis and Biological Activity of Some New Pyrazoline and Pyrrolo[3,4-c]pyrazole-4,6-dione Derivatives: Reaction of Nitrilimines with Some Dipolarophiles
- Author
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Omar A. Miqdad, Nadia G. Kandile, Hamdi M. Hassaneen, and Nada M. Abunada
- Subjects
Pyrazoline ,pyrrolo[3 ,4-c]pyrazole-4 ,6-dione ,nitrilimine ,dipolarophile ,biological activity ,Organic chemistry ,QD241-441 - Abstract
Several 1,3-diaryl-5-(cyano-, aminocarbonyl- and ethoxycarbonyl-)-2-pyrazoline, pyrrolo[3,4-c]pyrazole-4,6-dione and 1,3,4,5-tetraaryl-2-pyrazoline derivativeswere prepared by the reaction of nitrilimine with different dipolarophilic reagents. The newcompounds were characterized using IR, 1H-NMR, 13C-NMR and mass spectra. Biologicalscreening of some compounds is reported.
- Published
- 2008
- Full Text
- View/download PDF
24. An Isolable Gallium-Substituted Nitrilimine and its Reactivity with B-H, Si-H and B-B Bonds
- Author
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Anton Dmitrienko, Aishabibi Kassymbek, Dmitry G. Gusev, Melanie Pilkington, and Georgii I. Nikonov
- Subjects
010405 organic chemistry ,Nitrilimine ,Nitrene ,Organic Chemistry ,NacNac ,General Chemistry ,Borane ,010402 general chemistry ,01 natural sciences ,Medicinal chemistry ,Catalysis ,0104 chemical sciences ,3. Good health ,chemistry.chemical_compound ,chemistry ,Pyridine ,Diazo ,Reactivity (chemistry) ,Diborane - Abstract
Reaction of the Ga(I) compound NacNacGa ( 9 ) with the diazo compound N 2 CHSiMe 3 affords the nitrilimine compound NacNacGa(N-NCSiMe 3 )(CH 2 SiMe 3 ) ( 10 ). Carrying out this reaction in the presence of pyridine does not lead to C-H activation on the transient alkylidene NacNacGa=CHSiMe 3 , but generates a metallated diazo species NacNacGa(NHN=CHSiMe 3 )(CN 2 SiMe 3 ) ( 13 ) that further rearranges into the isonitrile compound NacNac- Ga(NHN=CHSiMe 3 )(N(NC)SiMe 3 ) ( 15 ). Reactions of 10 with the silane H 3 SiPh and the borane HBcat furnished products of 1,3 addition to the nitrilimine moiety NacNacGa{N(ER n )NCSiMe 3 }(CH 2 SiMe 3 ), whereas reaction with the diborane B 2 cat 2 gave the product of formal nitrene insertion into the B-B bond. DFT calculations suggest that the interaction of 9 with N 2 CHSiMe 3 proceeds via intermediate formation of an alkylidene compound that undergoes CH activation with a second molecule of N 2 CHSiMe 3 . Insertion into the B-B bond likely proceeds via an initial 1,3-addition of the diborane, followed by boryl migration to the former nitrene center.
- Published
- 2021
25. Photoinduced Porcine Gelatin Cross-Linking by Homobi- and Homotrifunctional Tetrazoles
- Author
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Vaghi, L, Monti, M, Marelli, M, Motto, E, Papagni, A, Cipolla, L, Vaghi, Luca, Monti, Mauro, Marelli, Marcello, Motto, Elisa, Papagni, Antonio, Cipolla, Laura, Vaghi, L, Monti, M, Marelli, M, Motto, E, Papagni, A, Cipolla, L, Vaghi, Luca, Monti, Mauro, Marelli, Marcello, Motto, Elisa, Papagni, Antonio, and Cipolla, Laura
- Abstract
Gelatin is a costless polypeptide material of natural origin, able to form hydrogels that are potentially useful in biomaterial scaffold design for drug delivery, cell cultures, and tissue engineering. However, gelatin hydrogels are unstable at physiological conditions, losing their features only after a few minutes at 37 °C. Accordingly, treatments to address this issue are of great interest. In the present work, we propose for the first time the use of bi- and trifunctional tetrazoles, most of them unknown to date, for photoinduced gelatin cross-linking towards the production of physiologically stable hydrogels. Indeed, after UV-B irradiation, aryl tetrazoles generate a nitrilimine intermediate that is reactive towards different functionalities, some of them constitutively present in the amino acid side chains of gelatin. The efficacy of the treatment strictly depends on the structure of the cross-linking agent used, and substantial improved stability was observed by switching from bifunctional to trifunctional cross-linker
- Published
- 2021
26. Synthesis of innovative multifunctional thermally-activated reactive species for elastomeric nanocomposite technology
- Author
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Monti, M, PAPAGNI, ANTONIO, MONTI, MAURO, Monti, M, PAPAGNI, ANTONIO, and MONTI, MAURO
- Abstract
The doctoral project was carried out in collaboration with Pirelli. The tire industry is always looking for new strategies to improve the performance of its products. The various elastomers used are not enough to obtain the desired characteristics. In order to increase its characteristics such as strength, adhesion, longevity, load, durability, it is necessary to add inorganic fillers such as silica and carbon black, but the interactions between rubber and filler are not always optimal. In this project, systems capable of both improving the dispersibility of fillers in the polymer matrix and systems capable of cross-linking elastomers have been investigated, in order to improve viscoelastic properties of the final material. The initial specifications required the synthesis of organic molecules stable at room temperature, but able to react thermally (above 100 ° C) with the polymer chain, forming strong and irreversible covalent bonds. Among the various classes of compounds were identified promising molecules capable to generate, at high temperatures, 1,3-dopolar nitrilimine-type species supplying cycloadducts with olefinic systems. We dealt with the synthesis of organic compounds, working on the nature of the substituents present in order to modulate their properties, the activation temperature and their reactivity. Each synthesized molecule was characterized by NMR, IR and thermogravimetric (TGA) analysis. Reactivity tests were also carried out on polymers to demonstrate their effective thermal anchoring. Subsequently, we focused on the synthesis of the functionalizers in sufficient quantity (in the order of grams) to conduct tests on tire compounds (polymer + filler + additives). These dynamic tests were carried out using RPA to highlight the possible positive effects of the functionalization of the polymers on the compound. Furthermore, tensile tests were carried out. The collected data, compared with those belonging to non-functionalized samples, served to highl, The doctoral project was carried out in collaboration with Pirelli. The tire industry is always looking for new strategies to improve the performance of its products. The various elastomers used are not enough to obtain the desired characteristics. In order to increase its characteristics such as strength, adhesion, longevity, load, durability, it is necessary to add inorganic fillers such as silica and carbon black, but the interactions between rubber and filler are not always optimal. In this project, systems capable of both improving the dispersibility of fillers in the polymer matrix and systems capable of cross-linking elastomers have been investigated, in order to improve viscoelastic properties of the final material. The initial specifications required the synthesis of organic molecules stable at room temperature, but able to react thermally (above 100 ° C) with the polymer chain, forming strong and irreversible covalent bonds. Among the various classes of compounds were identified promising molecules capable to generate, at high temperatures, 1,3-dopolar nitrilimine-type species supplying cycloadducts with olefinic systems. We dealt with the synthesis of organic compounds, working on the nature of the substituents present in order to modulate their properties, the activation temperature and their reactivity. Each synthesized molecule was characterized by NMR, IR and thermogravimetric (TGA) analysis. Reactivity tests were also carried out on polymers to demonstrate their effective thermal anchoring. Subsequently, we focused on the synthesis of the functionalizers in sufficient quantity (in the order of grams) to conduct tests on tire compounds (polymer + filler + additives). These dynamic tests were carried out using RPA to highlight the possible positive effects of the functionalization of the polymers on the compound. Furthermore, tensile tests were carried out. The collected data, compared with those belonging to non-functionalized samples, served to highl
- Published
- 2021
27. Photoinduced Porcine Gelatin Cross-Linking by Homobi- and Homotrifunctional Tetrazoles
- Author
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Mauro Monti, Marcello Marelli, Antonio Papagni, Elisa Motto, Laura Cipolla, Luca Vaghi, Vaghi, L, Monti, M, Marelli, M, Motto, E, Papagni, A, and Cipolla, L
- Subjects
food.ingredient ,Polymers and Plastics ,Science ,General. Including alchemy ,Bioengineering ,Gelatin ,Article ,Biomaterials ,gelatin ,chemistry.chemical_compound ,QD1-65 ,food ,Tissue engineering ,CHIM/06 - CHIMICA ORGANICA ,natural polymers ,Side chain ,Bifunctional ,QD1-999 ,QD146-197 ,tetrazole ,nitrilimine ,photochemistry ,Nitrilimine ,Aryl ,Organic Chemistry ,Combinatorial chemistry ,chemical cross-linking ,Chemistry ,chemistry ,Drug delivery ,Self-healing hydrogels ,hydrogel ,Inorganic chemistry ,tetrazoles - Abstract
Gelatin is a costless polypeptide material of natural origin, able to form hydrogels that are potentially useful in biomaterial scaffold design for drug delivery, cell cultures, and tissue engineering. However, gelatin hydrogels are unstable at physiological conditions, losing their features only after a few minutes at 37 °C. Accordingly, treatments to address this issue are of great interest. In the present work, we propose for the first time the use of bi- and trifunctional tetrazoles, most of them unknown to date, for photoinduced gelatin cross-linking towards the production of physiologically stable hydrogels. Indeed, after UV-B irradiation, aryl tetrazoles generate a nitrilimine intermediate that is reactive towards different functionalities, some of them constitutively present in the amino acid side chains of gelatin. The efficacy of the treatment strictly depends on the structure of the cross-linking agent used, and substantial improved stability was observed by switching from bifunctional to trifunctional cross-linkers.
- Published
- 2021
28. A Terminal Iron Nitrilimine Complex: Accessing the Terminal Nitride through Diazo N−N Bond Cleavage
- Author
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Frank W. Heinemann, Dominik Munz, Julian Messelberger, Karsten Meyer, Matthias E. Miehlich, and Sadig Aghazada
- Subjects
Trimethylsilyl ,010405 organic chemistry ,Diazomethane ,Ligand ,Nitrilimine ,Communication ,Diazo Compounds ,General Chemistry ,terminal nitrides ,Nitride ,010402 general chemistry ,01 natural sciences ,Communications ,Catalysis ,N−N activation ,3. Good health ,0104 chemical sciences ,chemistry.chemical_compound ,Crystallography ,iron ,chemistry ,Proton NMR ,Diazo ,N-heterocyclic carbenes ,Bond cleavage - Abstract
A novel method for the N−N bond cleavage of trimethylsilyl diazomethane is reported for the synthesis of terminal nitride complexes. The lithium salt of trimethylsilyl diazomethane was used to generate a rare terminal nitrilimine transition metal complex with partially occupied d‐orbitals. This iron complex 2 was characterized by CHN combustion analysis, 1H and 13C NMR spectroscopic analysis, single‐crystal X‐ray crystallography, SQUID magnetometry, 57Fe Mössbauer spectroscopy, and computational analysis. The combined results suggest a high‐spin d 6 (S=2) electronic configuration and an allenic structure of the nitrilimine ligand. Reduction of 2 results in release of the nitrilimine ligand and formation of the iron(I) complex 3, which was characterized by CHN combustion analysis, 1H NMR spectroscopic analysis, and single‐crystal X‐ray crystallography. Treatment of 2 with fluoride salts quantitatively yields the diamagnetic FeIV nitride complex 4, with concomitant formation of cyanide and trimethylsilyl fluoride through N−N bond cleavage., Chain reaction: A fluoride salt cleaves the N–N bond of an iron trimethylsilyl nitrilimine complex and generates the terminal nitride, fluorotrimethylsilane, and cyanide. The complementary reactivity of nitrilimine and azido ligands provides a new approach for the synthesis of metal terminal nitrido complexes.
- Published
- 2019
29. The Nitrilimine–Alkene Cycloaddition Regioselectivity Rationalized by Density Functional Theory Reactivity Indices
- Author
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Giorgio Molteni and Alessandro Ponti
- Subjects
1,3-dipolar cycloaddition ,nitrilimine ,alkene ,regioselectivity ,conceptual density functional theory ,reactivity indices ,softness ,Organic chemistry ,QD241-441 - Abstract
Conventional frontier molecular orbital theory is not able to satisfactorily explain the regioselectivity outcome of the nitrilimine–alkene cycloaddition. We considered that conceptual density functional theory (DFT) could be an effective theoretical framework to rationalize the regioselectivity of the title reaction. Several nitrilimine–alkene cycloadditions were analyzed, for which we could find regioselectivity data in the literature. We computed DFT reactivity indices at the B3LYP/6-311G(2d,p)//B3LYP/6-31G(d,p) and employed the grand potential stabilization criterion to calculate the preferred regioisomer. Experimental and calculated regioselectivity agree in the vast majority of cases. It was concluded that predominance of a single regioisomer can be obtained by maximizing (i) the chemical potential difference between nitrilimine and alkene and (ii) the local softness difference between the reactive atomic sites within each reactant. Such maximization can be achieved by carefully selecting the substituents on both reactants.
- Published
- 2017
- Full Text
- View/download PDF
30. Convenient generation of 1,3-dipolar nitrilimines and [3 + 2] cycloaddition for the synthesis of spiro compounds.
- Author
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Zhu, Mei-Jun, Ye, Rong, Shi, Wen-Jing, Sun, Jing, and Yan, Chao-Guo
- Subjects
- *
SPIRO compounds synthesis , *RING formation (Chemistry) , *NITRILIMINES - Abstract
[Display omitted] In the presence of 2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) as an oxidizer, the domino [3 + 2] cycloaddition reaction of aldohydrazones with 2-arylidene-1,3-indnaediones or 5-arylidene-1,3-dimethylbarbituric acids in acetonitrile at 80 °C afforded functionalized spiro[indene-2,4′-pyrazoles]-1,3-diones or 2,3,7,9-tetraazaspiro[4.5]dec-1-ene-6,8,10-triones in satisfactory yields. This reaction was believed to proceed with in situ generation of reactive 1,3-dipolar nitrilimine and its sequential 1,3-dipolar cycloaddition reaction with cyclic dipolarophiles. Thus, a new convenient synthetic method for the active dipolar nitrilimine was successfully developed. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
31. 1,3-Dipolar cycloaddition of diphenylnitrilimine and 5-arylmethylidene-1-phenyl-1,5,6,7-tetrahydro-4H-indazol-4-ones to afford novel spiro[indazole-5,3′-pyrazole] derivatives
- Author
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Demin Ren, Xiaofang Li, and Guoqiang Kuang
- Subjects
Indazole ,010405 organic chemistry ,Chemistry ,Nitrilimine ,Organic Chemistry ,Nuclear magnetic resonance spectroscopy ,Pyrazole ,010403 inorganic & nuclear chemistry ,01 natural sciences ,Medicinal chemistry ,Cycloaddition ,0104 chemical sciences ,chemistry.chemical_compound ,1,3-Dipolar cycloaddition ,Triethylamine ,Single crystal - Abstract
Novel 4'-aryl-1,2',5'-triphenyl-2',4',6,7-tetrahydrospiro[indazole-5,3'-pyrazol]-4(1H)-ones have been synthesized in moderate yields by 1,3-dipolar cycloaddition of 5-arylmethylidene-1-phenyl-1,5,6,7-tetrahydro-4H-indazol-4-ones and diphenylnitrilimine, generated in situ from N-phenylbenzohydrazonoyl chloride and triethylamine. According to structural analyses by NMR spectroscopy and single crystal X-ray diffraction method, the reaction proceeds regioselectively affording products with C(5)–C(3') connectivity at the spiro center.
- Published
- 2018
32. Synthesis of innovative multifunctional thermally-activated reactive species for elastomeric nanocomposite technology
- Author
-
MONTI, MAURO, Monti, M, and PAPAGNI, ANTONIO
- Subjects
nitrilimine ,polymer ,CHIM/06 - CHIMICA ORGANICA ,functionalization ,compatibilizer ,crosslinking - Abstract
The doctoral project was carried out in collaboration with Pirelli. The tire industry is always looking for new strategies to improve the performance of its products. The various elastomers used are not enough to obtain the desired characteristics. In order to increase its characteristics such as strength, adhesion, longevity, load, durability, it is necessary to add inorganic fillers such as silica and carbon black, but the interactions between rubber and filler are not always optimal. In this project, systems capable of both improving the dispersibility of fillers in the polymer matrix and systems capable of cross-linking elastomers have been investigated, in order to improve viscoelastic properties of the final material. The initial specifications required the synthesis of organic molecules stable at room temperature, but able to react thermally (above 100 ° C) with the polymer chain, forming strong and irreversible covalent bonds. Among the various classes of compounds were identified promising molecules capable to generate, at high temperatures, 1,3-dopolar nitrilimine-type species supplying cycloadducts with olefinic systems. We dealt with the synthesis of organic compounds, working on the nature of the substituents present in order to modulate their properties, the activation temperature and their reactivity. Each synthesized molecule was characterized by NMR, IR and thermogravimetric (TGA) analysis. Reactivity tests were also carried out on polymers to demonstrate their effective thermal anchoring. Subsequently, we focused on the synthesis of the functionalizers in sufficient quantity (in the order of grams) to conduct tests on tire compounds (polymer + filler + additives). These dynamic tests were carried out using RPA to highlight the possible positive effects of the functionalization of the polymers on the compound. Furthermore, tensile tests were carried out. The collected data, compared with those belonging to non-functionalized samples, served to highlight a variation in the viscoelastic properties (G ’, G’ ’, tanD). Finally, given the versatility of the species used, structural changes were made, so that they can be used for different applications; according to the directives requested by the company. The last part of the doctorate was dedicated to the scale up of some compounds identified as the most promising for industrial application. In addition, six months were spent abroad, at the University of Strasbourg, where new systems for polymer functionalization, based on non-covalent interactions (e.g. hydrogen bonds), were studied. The desired compounds were synthetized and characterized, and their properties were investigated, performing rheological measurements to measure the change of some properties such as viscosity. The doctoral project was carried out in collaboration with Pirelli. The tire industry is always looking for new strategies to improve the performance of its products. The various elastomers used are not enough to obtain the desired characteristics. In order to increase its characteristics such as strength, adhesion, longevity, load, durability, it is necessary to add inorganic fillers such as silica and carbon black, but the interactions between rubber and filler are not always optimal. In this project, systems capable of both improving the dispersibility of fillers in the polymer matrix and systems capable of cross-linking elastomers have been investigated, in order to improve viscoelastic properties of the final material. The initial specifications required the synthesis of organic molecules stable at room temperature, but able to react thermally (above 100 ° C) with the polymer chain, forming strong and irreversible covalent bonds. Among the various classes of compounds were identified promising molecules capable to generate, at high temperatures, 1,3-dopolar nitrilimine-type species supplying cycloadducts with olefinic systems. We dealt with the synthesis of organic compounds, working on the nature of the substituents present in order to modulate their properties, the activation temperature and their reactivity. Each synthesized molecule was characterized by NMR, IR and thermogravimetric (TGA) analysis. Reactivity tests were also carried out on polymers to demonstrate their effective thermal anchoring. Subsequently, we focused on the synthesis of the functionalizers in sufficient quantity (in the order of grams) to conduct tests on tire compounds (polymer + filler + additives). These dynamic tests were carried out using RPA to highlight the possible positive effects of the functionalization of the polymers on the compound. Furthermore, tensile tests were carried out. The collected data, compared with those belonging to non-functionalized samples, served to highlight a variation in the viscoelastic properties (G ’, G’ ’, tanD). Finally, given the versatility of the species used, structural changes were made, so that they can be used for different applications; according to the directives requested by the company. The last part of the doctorate was dedicated to the scale up of some compounds identified as the most promising for industrial application. In addition, six months were spent abroad, at the University of Strasbourg, where new systems for polymer functionalization, based on non-covalent interactions (e.g. hydrogen bonds), were studied. The desired compounds were synthetized and characterized, and their properties were investigated, performing rheological measurements to measure the change of some properties such as viscosity.
- Published
- 2021
33. Synthesis of novel spiro(indolizine-pyrazole) derivatives via 1,3-dipolar cycloaddition of nitrilimine.
- Author
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Shaowei Zhang, Xiaolian Hu, Hongwen Tao, Haochong Liu, and Xiaofang Li
- Subjects
- *
RING formation (Chemistry) , *NITRILIMINES , *TRIETHYLAMINE , *INDOLE , *X-ray diffraction , *CHEMICAL synthesis - Abstract
The 1,3-dipolar cycloaddition of nitrilimine, generated in situ from N'-phenylbenzohydrazonoyl chloride and triethylamine, to 7-arylmethylidene-6,7-dihydroindolizin-8(5H)-one afforded novel 4'-aryl-2',5'-diphenyl-2',4',5,6-tetrahydro-8H-spiro(indolazine-7,3'- pyrazol)-8-ones in moderate yields. The structures of all the products were characterised thoroughly by NMR, infrared spectroscopy and HRMS. The structure and stereochemistry was confirmed by x-ray diffraction analysis [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
34. Heterocyclic synthesis using nitrilimines: Part 19. Synthesis of novel 1,3,5-trisubstituted-1,2,4-triazoles.
- Author
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Dalloul, Hany M.M.
- Abstract
This paper describes the synthesis of a new series of 1,3,5-trisubstituted-1,2,4-triazoles by 1,3-dipolar cycloaddition reaction of C -phenyl-aminocarbonyl- N -arylnitrilimines with guanidine derivatives. The structures of the newly synthesized compounds were elucidated by spectral methods (IR, 1 H NMR, 13 C NMR and MS spectroscopy) and elemental analysis. The microbial features of the synthesized compounds were studied using well-established methods from the literature. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
35. Synthesis of substituted 2,4,5,6-tetrahydrocyclopenta[c]pyrazoles and 2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazoles by intramolecular nitrilimine cycloaddition.
- Author
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Winters, Michael P., Teleha, Christopher A., and Sui, Zhihua
- Subjects
- *
HETEROCYCLIC compounds synthesis , *PYRAZOLES , *INTERMOLECULAR interactions , *NITRILIMINES , *RING formation (Chemistry) , *BROMIDES , *CHEMICAL derivatives - Abstract
Abstract: Both substituted 2,4,5,6-tetrahydrocyclopenta[c]pyrazoles and 2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazoles have been synthesized by the 3+2 intramolecular dipolar cycloaddition of nitrilimines to alkynes. This cyclization has been extended to more versatile 3-bromo derivatives by the use of alkynylbromides as dipolarophiles. [Copyright &y& Elsevier]
- Published
- 2014
- Full Text
- View/download PDF
36. Nucleophilic Trapping Nitrilimine Generated by Photolysis of Diaryltetrazole in Aqueous Phase.
- Author
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Yixin Zhang, Wujun Liu, and Zongbao K. Zhao
- Subjects
- *
NITRILIMINES , *ACRYLAMIDE , *ACRYLATES , *MASS spectrometry , *IMINO acids - Abstract
Nitrilimine generated by photolysis of diaryltetrazole in aqueous phase under mild conditions was trapped by nucleophiles including amines and thioalcohols. The representative products were characterized, while products with all 20 natural amino acids and a peptide were observed by MALDI-TOF mass spectroscopy. Competitive studies showed that this reaction also occurred in the presence of acrylamide. These results provided new information for understanding the potential side reactions when tetrazole-alkene pairs were used as a bioorthogonal reaction in labeling proteins and related studies in buffered systems. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
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37. Ring-Degenerate Rearrangement Resulting from the Azo Coupling Reaction of a 3-Aryl-1,3a,6a-triazapentalene
- Author
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Tomas Opsomer, Yingchun Wang, Wim Dehaen, and Luc Van Meervelt
- Subjects
Fluorophore ,010405 organic chemistry ,Nitrilimine ,Aryl ,Organic Chemistry ,Azo coupling ,010402 general chemistry ,Cleavage (embryo) ,Ring (chemistry) ,01 natural sciences ,Small molecule ,0104 chemical sciences ,chemistry.chemical_compound ,chemistry ,Polymer chemistry ,Molecule - Abstract
The 3-(4-(methoxycarbonyl)phenyl)triazapentalene is a highly fluorescent small molecule which is readily accessible via a two-step synthesis. In the search for postfunctionalization methods, a radical CH-arylation with diazonium salts was attempted. However, azo coupling resulted in a ring-degenerate rearrangement toward a 2-aryl-4-azotriazapentalene, which was confirmed via crystallographic analysis. A mechanism involving the generation of a nitrilimine is proposed. In addition, reduction of the azo group led to cleavage of the triazapentalene core. The present results further demonstrate the sensitivity of the triazapentalene fluorophore. ispartof: The Journal of Organic Chemistry vol:84 issue:14 pages:9434-9439 ispartof: location:United States status: Published online
- Published
- 2020
38. Unveiling the Different Chemical Reactivity of Diphenyl Nitrilimine and Phenyl Nitrile Oxide in [3+2] Cycloaddition Reactions with (R)-Carvone through the Molecular Electron Density Theory
- Author
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Mar Ríos-Gutiérrez, Luis R. Domingo, Ali Oubella, M. Esseffar, and My Youssef Ait Itto
- Subjects
Models, Molecular ,Nitrile ,molecular mechanisms ,Pharmaceutical Science ,010402 general chemistry ,nitrilimines ,01 natural sciences ,Article ,Analytical Chemistry ,lcsh:QD241-441 ,chemistry.chemical_compound ,lcsh:Organic chemistry ,Computational chemistry ,Drug Discovery ,Nitriles ,Single bond ,Reactivity (chemistry) ,Physical and Theoretical Chemistry ,Chemoselectivity ,Carbenoid ,Cycloaddition Reaction ,Molecular Structure ,010405 organic chemistry ,Chemistry ,Nitrilimine ,Organic Chemistry ,Biphenyl Compounds ,molecular electron density theory ,[3+2] cycloadditions ,Cycloaddition ,0104 chemical sciences ,Chemistry (miscellaneous) ,chemoselectivity ,nitrile oxides ,Molecular Medicine ,Quantum Theory ,Density functional theory - Abstract
The [3+2] cycloaddition (32CA) reactions of diphenyl nitrilimine and phenyl nitrile oxide with (R)-carvone have been studied within the Molecular Electron Density Theory (MEDT). Electron localisation function (ELF) analysis of these three-atom-components (TACs) permits its characterisation as carbenoid and zwitterionic TACs, thus having a different reactivity. The analysis of the conceptual Density Functional Theory (DFT) indices accounts for the very low polar character of these 32CA reactions, while analysis of the DFT energies accounts for the opposite chemoselectivity experimentally observed. Topological analysis of the ELF along the single bond formation makes it possible to characterise the mechanisms of these 32CA reactions as cb- and zw-type. The present MEDT study supports the proposed classification of 32CA reactions into pdr-, pmr-, cb- and zw-type, thus asserting MEDT as the theory able to explain chemical reactivity in Organic Chemistry.
- Published
- 2020
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39. Theoretical Study of Reaction Between Nitrilimine and 1,4 Oxazine 2 Carboxylate by MP2 and DFT Methods
- Author
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F. Hlimi, Najia Komiha, Khadija Marakchi, Mohammed Salah, H. El-Hadki, and Oum Keltoum Kabbaj
- Subjects
Green chemistry ,chemistry.chemical_classification ,010405 organic chemistry ,Nitrilimine ,Supramolecular chemistry ,General Chemistry ,Radiation chemistry ,010402 general chemistry ,01 natural sciences ,Biochemistry ,0104 chemical sciences ,Coordination complex ,Elsevier Biobase ,chemistry.chemical_compound ,chemistry ,Computational chemistry ,Drug Discovery ,Theoretical chemistry ,Environmental Chemistry ,Carboxylate - Abstract
The regioselectivity of the reaction between phenyldiazen-1-ium-1-ylidene p-tolyl methanide and ethyl 4-benzoyl-4H-benzo [1,4]oxazine-2-carboxylate were studied by means of the DFT/B3LYP method coupled by the 6-31g(d) basis and MP2 in connection with 6-31G(d) and 6-31G+(d,p) basis set. The mechanism of this regioselectif reaction has performed by transition state optimization, evaluation of the potential energy surface, calculation of IRC and reactivity indices. Location and verification of minima and transition structures have been realized by using the Berny's algorithm. The process of formation of the two regioisomers is achieved through concerted and asynchronous mechanism. The results are in good agreement with the experimental data.
- Published
- 2018
40. 1, 3-Dipolar cycloaddition reactions: Synthesis of 5-benzyl-1-(2′,4′-dibromophenyl)-3-(4″-substituted phenyl)-3a,4,6,6a-tetrahydro-1 H, 5 H-pyrrolo[3,4- c]pyrazole-4,6-dione derivatives.
- Author
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KAUR, MANPREET, SINGH, BALDEV, and SINGH, BALJIT
- Subjects
- *
ZWITTERIONS , *RING formation (Chemistry) , *SUBSTITUTION reactions , *CHEMICAL yield , *ISOMERS , *CHEMICAL reactions - Abstract
1,3-Dipolar cycloaddition of nitrilimines 3 with N-benzyl maleimide 4 has provided 5-benzyl-1-(2′,4′-dibromophenyl)-3-(4″-substituted phenyl)-3a,4,6,6a-tetrahydro-1 H,5 H-pyrrolo[3,4- c]pyrazole-4,6-dione derivatives 5 in excellent yield as the only isomer through a concerted pathway. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]
- Published
- 2013
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41. THEORETICAL AND EXPERIMENTAL STUDY ON THE REGIOSELECTIVITY OF ACRYLONITRILE AND METHYLMETHACRYLATE 1,3-DIPOLAR CYCLOADDITION TO SOME NITRILIMINES.
- Author
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MOEINPOUR, F., BAKAVOLI, M., DAVOODNIA, A., and MORSALI, A.
- Subjects
- *
REGIOSELECTIVITY (Chemistry) , *ACRYLONITRILE , *METHYL methacrylate , *RING formation (Chemistry) , *DIPOLE moments , *IMINES , *PYRAZOLES , *ACTIVATION energy - Abstract
1,3-dipolar cycloaddition between acrylonitrile and methylmethacrylate with two N-(4-bromophenyl)-C-(4-substituted) nitrilimines which were generated in situ afforded the new pyrazoles. The regioselectivity and reactivity of these reactions has been investigated on the basis of density functional theory (DFT)-based reactivity indexes and activation energy calculations. The theoretical 13C NMR chemical shifts of the cycloadducts which were obtained by GIAO method were comparable with the observed values. [ABSTRACT FROM AUTHOR]
- Published
- 2012
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42. Flash vacuum pyrolysis of azolylacroleins and azolylbutadienes
- Author
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Lucero, Paola L., Peláez, Walter J., Riedl, Zsuzsanna, Hajós, György, Moyano, Elizabeth L., and Yranzo, Gloria I.
- Subjects
- *
ACROLEIN , *PYROLYSIS , *BUTADIENE , *TETRAZOLES , *NITROGEN , *IMINES , *FRAGMENTATION reactions - Abstract
Abstract: 2-Aryl-5-acroleinyl-1,2,3,4-tetrazoles (1a–d) and 2-aryl-5-butadienyl-1,2,3,4-tetrazoles (1e–g) were subjected to flash vacuum pyrolysis. Acroleinyl derivatives resulted in nitrogen extrusion to give nitrilimines followed by ring closure to give the corresponding indazoles 3a–d in good yields. On the other hand, butadiene derivatives underwent ring fragmentation to give p-substituted anilines without formation of the expected indazoles. Differences between thermal behaviour of 2-(4-chlorophenyl)-5-acroleinyl-1,2,3,4-tetrazole (1c) and 1-(4-chlorophenyl)-4-acroleinyl-1,2,3-triazole (2) were studied in details. DFT calculations have been used to examine the nitrilimine and carbene nature of the intermediates involved in the thermal reactions of azolyl derivatives. [Copyright &y& Elsevier]
- Published
- 2012
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43. Synthesis and stereochemistry of some novel dihydropyrrolo[3,4- c]pyrazoles.
- Author
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Dürüst, Yaşar, Yıldırım, Muhammet, Fronczek, Chris, and Fronczek, Frank
- Abstract
Eleven novel dihydropyrrolo[3,4- c]pyrazole derivatives were obtained by the reaction of chiral (1 R)- N-(1-phenylethyl)maleimide and C,N-aryl-substituted nitrilimines. The reaction afforded the cycloadducts as a regioisomeric mixture which can be separable in some cases. The structure and stereochemistry of cycloadducts were assigned on the basis of infrared (IR), H and C nuclear magnetic resonance (NMR), mass and X-ray spectra, optical rotation measurements, and CHN analyses. Graphical Abstract: [Figure not available: see fulltext.]. [ABSTRACT FROM AUTHOR]
- Published
- 2012
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44. Synthesis and antiproliferative evaluation of 3,5-disubstituted 1,2,4-triazoles containing flurophenyl and trifluoromethanephenyl moieties
- Author
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Wang, Li-Ya, Tseng, Wen-Che, Wu, Tian-Shung, Kaneko, Kimiyoshi, Takayama, Hiroyuki, Kimura, Masayuki, Yang, Wen-Chin, Wu, Jin Bin, Juang, Shin-Hun, and Wong, Fung Fuh
- Subjects
- *
TRIAZOLES , *ANTINEOPLASTIC agents , *RING formation (Chemistry) , *ALDEHYDES , *CANCER cells , *FLUOROFORM , *FLUORINE compounds - Abstract
Abstract: An efficient 1,3-dipolar cycloaddition method was performed for the synthesis of a series of monofluoro- and trifluoromethane-3,5-disubstituted 1,2,4-triazoles. This efficient cycloaddition method was to react hydrazonoyl hydrochlorides with a series of aldehydes in the presence of NEt3 as catalytic basic agent to provide the corresponding product in 28–94%. Their growth inhibitory results against cancer cells indicated that some of the fluorine- and trifluoromethane-containing compounds could effectively inhibit the growth of NCI-H226 and T-cell leukemia (Jurkat) cells. Among the compounds, trifluoromethane-containing 1,2,4-triazoles possessed the five-membered ring groups on the C-5 position of the triazolic ring, including cyclopentyl, 3-furyl, 3-thienyl, and 2-pyrrolyl, possessed the significant inhibitory activity for NCI-H226 cancer cells. [Copyright &y& Elsevier]
- Published
- 2011
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45. Synthesis of Spiroheterocycles Containing Thiadiazole Thiadiazine and Triazine Moieties from Nitrilimines.
- Author
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Dalloul, Hany M. M.
- Subjects
- *
ORGANIC synthesis , *HETEROCYCLIC compounds , *AZOLES , *TRIAZINES , *IMINES , *RING formation (Chemistry) , *SILICON , *PHOSPHORUS compounds , *AMINO acids - Abstract
A series of 5-substituted 1-methyl-3-phenyl-4,5-dihydro-1,2,4-triazin-6-ones was prepared by the reaction of α-amino acid methyl esters with appropriate nitrilimines and treated with phosphorus pentasulfide to afford 5-substituted 1-methyl-3-phenyl-4,5-dihydro-1,2,4-triazin-6-thiones. When 1,2,4-triazin-6-thiones were allowed to react with nitrilimine, the novel 4,6-dimethyl-2,8-di-phenyl-10-substituted-1-thia-3,4,6,7,9-pentaazaspiro[4.5]dec-2,7-dienes were obtained and confirmed by their elemental analyses and spectral data. Some of the synthesized compounds were tested in vitro for their antimicrobial activity. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file. GRAPHICAL ABSTRACT [image omitted] [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
46. ‘One-flask’ synthesis to 3,5-disubstituted 1,2,4-triazoles from aldehydes with hydrazonoyl hydrochlorides via 1,3-dipolar cycloaddition
- Author
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Tseng, Wen-Che, Wang, Li-Ya, Wu, Tian-Shung, and Wong, Fung Fuh
- Subjects
- *
ORGANIC synthesis , *TRIAZOLES , *ALDEHYDES , *CHLORIDES , *RING formation (Chemistry) , *INTERMEDIATES (Chemistry) , *HYDROXYLAMINE , *AROMATIC compounds - Abstract
Abstract: A new ‘one-flask’ synthesis of 3,5-disubstituted 1,2,4-triazoles has successfully been developed to synthesize a series of 3,5-disubstituted 1,2,4-triazoles. The transformation involves the 1,3-dipolar cycloaddition reaction of hydrazonoyl hydrochlorides with oxime intermediates prepared from aldehydes with hydroxylamine hydrochloride in the presence of excess amount of triethylamine. In this ‘one-flask’ 1,3-dipolar reaction, hydrazonoyl hydrochlorides was concerned as the masked 1,3-dipole nitrilimine under basic condition. Furthermore, this newly developed methodology can be applied to various aldehyde substrates including aliphatic, cyclic aliphatic, aromatic, and heterocyclic aldehydes. [Copyright &y& Elsevier]
- Published
- 2011
- Full Text
- View/download PDF
47. Regioselective 1,3-dipolar cycloaddition of nitrilimines to 2-methyl-2-vinyl oxirane
- Author
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Yıldırım, Muhammet and Dürüst, Yaşar
- Subjects
- *
RING formation (Chemistry) , *ETHYLENE oxide , *PYRAZOLES , *X-ray diffraction , *STEREOCHEMISTRY , *CHEMICAL structure - Abstract
Abstract: 1,3-Dipolar cycloaddition of in situ generated C,N-diaryl nitrilimines to 2-methyl-2-vinyl oxirane gives rise to the regioselective formation of novel 5-(2-methyloxiranyl)-4,5-dihydropyrazole derivatives in moderate to good yields. The structures and stereochemistries of the new cycloadducts were confirmed by spectroscopic/physical methods including X-ray diffraction data. [Copyright &y& Elsevier]
- Published
- 2011
- Full Text
- View/download PDF
48. Synthesis, UV–Vis spectra, and Hammett correlation of some novel bis(dihydropyrrolo[3,4- c]pyrazoles).
- Author
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Dürüst, Yaşar and Yıldırım, Muhammet
- Abstract
Twenty-nine novel bis(dihydropyrrolo[3,4- c]pyrazole) derivatives were obtained by reacting C,N-phenyl-substituted nitrilimines generated in situ from corresponding hydrazonyl chlorides with bismaleimides. The structures were elucidated by physical and spectroscopic methods [m.p., R, infrared (IR), H nuclear magnetic resonance (NMR), C NMR, correlation spectroscopy (COSY), heteronuclear correlation (HETCOR), nuclear Overhauser effect (NOE), and high-resolution mass spectrometry (HRMS)]. Also, Hammett correlation graphs were obtained between Hammett constants σ and λ values of bis(pyrrolopyrazoles) carrying p-substituted phenyl-ring-bearing electron-withdrawing and electron-donating groups and discussed in terms of substituent effects. Graphical Abstract: [Figure not available: see fulltext.]. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
49. 1,3-Dipolar cycloaddition of N-[4-nitrophenyl]-C-[2-furyl] nitrilimine with some dipolarophiles: A combined experimental and theoretical study
- Author
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Bakavoli, M., Moeinpour, F., Davoodnia, A., and Morsali, A.
- Subjects
- *
IMINES , *RING formation (Chemistry) , *VINYL acetate , *STYRENE , *PYRAZOLES , *DENSITY functionals , *REACTIVITY (Chemistry) , *METHANOL - Abstract
Abstract: Reaction of vinyl acetate (3), 2-propyne-1-ol (4) and styrene (5) as dipolarphiles with N-[4-nitrophenyl]-C-[2-furyl] nitrilimine which was generated in situ has been shown to afford 3-(furan-2-yl)-1-(4-nitrophenyl)-4,5-dihydro-1H-pyrazol-5-yl acetate (6), (3-(furan-2-yl)-1-(4-nitrophenyl)-1H-pyrazol-5-yl)methanol (8) and 3-(furan-2-yl)-1-(4-nitrophenyl)-5-phenyl-4,5-dihydro-1H-pyrazole (10). Reactivity and regiochemistry of these reactions were investigated using DFT-based reactivity indexes. [Copyright &y& Elsevier]
- Published
- 2010
- Full Text
- View/download PDF
50. Heterocyclic synthesis using nitrilimines: Part 10. Synthesis of some new 1,3,4,6-tetrasubstituted 1,2,4,5-tetrazines.
- Author
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Dalloul, Hany M. and Abu-Shawish, Hazem M.
- Subjects
- *
TETRAZINE , *ORGANONITROGEN compounds , *NITROGEN compounds , *ORGANIC compounds , *CHEMICAL reactions , *METHYL hydrazine , *CARCINOGENS , *HYDRAZINES , *HALIDES - Abstract
A new series of 1,3,4,6-tetrasubstituted 1,2,4,5-tetrazines were synthesized from the cycloaddition reaction of methylhydrazones of alkanal and cycloalkanal with appropriate hydrazonoyl halides. [ABSTRACT FROM AUTHOR]
- Published
- 2008
Catalog
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