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1,3-Bis-3-(4-chlorophenyl)-2,3-dihydroquinazolin-4(1H)-on-2-thioxopropane (C), a quinazoline derivative was synthesized and well-characterized in order to evaluate its potential to act as VEGFR-2 a...

Synthesis of some new 5-phenyl-2,4-dihydro-3H-1,2,4-triazole derivatives as hybrids with 1,2,3-triazoles via a flexible bonding, and their antioxidant and antibacterial activity have been studied. IR, 1H and 13C NMR spectra have confirmed the chemical structures of the compounds. Antioxidant activity has been compared with BHA as a standard. Several tested compounds have demonstrated highly potent antioxidant activity. Antibacterial activity of the products has been evaluated against Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria, and some of those have been characterized as the most potent against E. coli and S. aureus. Molecular docking to the active sites of VIM-2 Metallo-β-Lactamase (MBL) as a target protein has revealed that most compounds have displayed minimal binding energy and good affinity toward the active pocket.

We report the synthesis and biological evaluation of bis benzylidne cyclohexanone derivatives 2,6-di(4-fluorobenzylidene)cyclohexanone 3a and (2E,6E)‐2,6‐bis({[4‐(trifluoromethyl)phenyl]methylidene})cyclohexanone 3b . Compound 3b crystallized in the monoclinic space group P 2 1 / n with unit cell parameters a = 29.3527(12) A, b = 8.3147(3) A, c = 32.7452(14) A, β = 112.437(2)°, and V = 7386.8(5) A 3 , Z = 16, and R int = 0.072 at T = 100 K. The asymmetric unit contains four independent molecules, each of which has slight differences in the bond lengths and angles. One non-classical C11D–H11F⋯F3A hydrogen bond connects the molecules. Density functional theory was used to optimize the structures and calculate the natural charges, dipole moments, frontier molecular orbitals, and NMR and UV–Vis spectroscopic properties, which are discussed and compared with the experimental data. The synthetic derivatives were evaluated for α-glucosidase inhibitory activity, and we found that compound 3a (IC 50 = 96.3 ± 0.51 μM) is a potent α-glucosidase inhibitor, showing superior activity to the standard drug acarbose (IC 50 = 841 ± 1.73 μM). Compound 3b (IC 50 = 7.92 ± 1.3 μg/mL) was found to be a potent antileishmanial compound, especially compared to the antileishmanial drugs pentamidine (IC 50 = 5.09 ± 0.04 μM) and amphotericine B (IC 50 = 0.29 ± 0.05 μg/mL). In addition, 3a and 3b have cytotoxic effects against PC3 (prostate cancer), HeLa (cervical cancer), and MCF-3 (breast cancer) cell lines. Docking study for compounds activity was performed with Openeye software in order to understanding their pose of interaction in the target receptors.

A series of 6-methylpyrimidin-4(3H)-one and oxo-1,2,4-triazolo[4,3-a]pyrimidine derivatives (1-18) was designed to meet the urgent need for novel antibacterial and antioxidant agents. The in vitro antibacterial activity revealed that most of the compounds exhibited a good inhibitory effect on Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria with MIC values in the range of 55–200 µg/mL for E. coli and 125–700 µg/mL for S. aureus. (E)-2-(2-(4-methoxybenzylidene)hydrazinyl)-6-methylpyrimidin-4(3H)-one (8) was the most active compound (MIC = 55 and 125 µg/mL against E. coli and S. aureus, respectively). All compounds exhibited antioxidant activity ranged from weak to moderate and high. The obtained findings revealed that compounds 3, 5, 6, 9, 16, and 18 have superiority among all compounds, demonstrating the highest capacity to deplete DPPH (1,1-diphenyl-2-picrylhydrazyl), compared to α-tocopherol, as a standard antioxidant agent. Surprisingly, compound 3 (2-hydrazinyl-6-methylpyrimidin-4(3H)-one) showed significantly higher antioxidant activity (EC50 = 2.12 µg/mL) than α-tocopherol (EC50 = 9.16 µg/mL). Molecular docking, drug-likeness data, physicochemical properties, and ADMET parameters of the compounds were in silico computed. The derivatives presented good properties for Lipinski’s parameters, poor solubility in the aqueous medium (Log S of -1.27 to -5.45), and PSA ≤140, indicating good permeability in biological membranes and gastrointestinal absorption. Molecular docking to the active sites of penicillin-binding protein and NADPH oxidase revealed that most compounds displayed minimal binding energy and have a good affinity toward the active pocket.

New glycosylhydrazinyl-pyrazolo[1,5-c]pyrimidines were synthesized by the reaction of respective 5-aryl-7-hydrazino-2-phenylpyrazolo[1,5-c]pyrimidines (1a-d) with glucose, galactose, and xylose in ethanol. Their glycopyranosyl structures were reasoned to be in chair conformations and each have hydrazine moiety in the β-configuration. Also, pyrazolo[1,5-c]triazolo[4,3-a]pyrimidines derivatives were synthesized by the reaction of 1a-d with benzoic acid in the presence of phosphorousoxy chloride or by the reaction with benzaldehyde derivatives followed by cyclization in the presence of bromine. All structures of the compounds were confirmed from their IR, 1H, 13C, DPET-135°, 1H-1H COSY, 1H-13C HMQC, 13C-1H HMBC spectra and microanalysis. The synthesized compounds showed inhibition of proliferation of MCF-7 human breast cancer cells with IC50 values ranging from 0.56 to 8.86 µg/ml. Some of the most active compounds showed acceptable predicted pharmacokinetics and drug-likeness properties.

Aim and Objective: Reaction of phthalic anhydride (1) with thiocarbohydrazide (2) in methanol gave the intermediate (6) whose boiling in water or ethanol gave N-(1,3-dioxoisoindol-2-yl)aminothiocarbohydrazide (5); where its Condensation with aldehydes and aldoses 9a-d afforded the respective thiosemicarbazide derivatives. The manno-derivative 10, the D-galacto derivative 11 and the L-arabino derivative 12 exist in the cyclic pyranosyl structures undergo equilibration, in solution of DMSO, with their acyclic structures. Dehydrative cyclization to the thiadiazoline derivatives and the acyclo C-nucleoside was done by refluxing in acetic anhydride. Materials and Methods: Commercially available solvents and reagents were purified according to the standard procedures. Thin layer chromatography (TLC) was performed on plastic plates Silica Gel 60 F254 (E-Merk, layer thickness 0.2 mm) with detection by UV light absorption. IR spectra were recorded for the compounds in a KBr matrix with a Unicam SP 1025 spectrophotometer. NMR spectra were measured with Jeol spectrometer (500 MHz). Chemical shifts (δ) are given in ppm relative to the signal for TMS as internal standard, and coupling constants in Hz. The 13C NMR spectra were recorded with JEOL spectrometer at 125.7 MHz. The assignments of 1H NMR spectra were based on chemical-shift correlation DQFCOSY spectra, while the assignment of 13C NMR spectra were based on heteronuclear multiple quantum coherence, HMQC experiments. Results: The N-(1,3-dioxoisoindol-2-yl)aminothiocarbohydrazide (5) was prepared, which incorborated the 1,3-dioxoisoindole ring that linked to thiosemicarbazide moiety. Such feature found to be excellent precursor for the synthesis of hybrid of bi-heterocycles, the dioxoisoindolyl and thiadiazoline rings which could of potential biological activity. The reaction of thiocarbohydrazide with phthalic anhydride in a detailed manner and investigate its further reaction with aromatic aldehydes and sugars, then converting them to the target biheterocycles and nucleosides was studied. The conformations of the acyclic alditolyl residues or the acyclic Cnucleosides have been explained. Conclusion: The new functionalized isoindolyl ring with thiosemicarbazide as in N-(1,3-dioxoisoindol-2- yl)aminothiocarbohydrazide (5) resulted from the reaction of phthalic anhydride with thiocarbohydrazide via the intermediate open chain derivative 6. It is a valuable precursor for the synthesis of thiosemicarbazones containing sugar moieties 10-13. Their solutions in DMSO-d6 showed that the products exist in one form after immediate dissolution that equilibrated with time to show a mixture of acyclic and cyclic forms. They have been exploited as scaffolds for generation of potential hybrids of thiadiazoline derivatives containing isoindolyl rings as well as their acyclo C-nucleosides 10a-13a and 14-15. The conformations of the acyclic alditolyl residues or the acyclic C-nucleosides have been deduced from their spectral analysis.

In this work, the synthesis of novel 1,2,4-triazole thioglycoside heterocycles 4, 5, and 8 were achieved by the reaction of 1,2,3,4,6-penta-O-acetyl-β- d -glucopyranose (2) and galactopyranose (3) with 4-((4-arylidene)amino)-5-methyl-1,2,4-triazole-3-thiol derivatives 1 and 6 in the presence of boron trifluoride etherate (BF3·Et2O) as a promoter under nitrogen in CH2Cl2. Exclusive β-stereoselectivity of the formed glycosidic bond was confirmed by X-ray analysis of 4 as well as its spectral data. Different stereoselectivities were observed when the acceptor 9, having an ortho phenolic OH group, was coupled with the donors 2 or 3, under the same reaction conditions. Similarly, treatment of a mixture of 1-O-acetyl-2,3,5-tri-O-benzoyl-β- d -ribofuranose (16) and the thiol acceptors 1 and 15 afforded the β-thioribofuranosides 17 and 18, respectively. The β-stereoselectivity of the reaction was confirmed by 1H, 13C, 1H 1H 2D, and 1H 13C 2D NMR spectral analysis.

Owing to their structural novelty and inherent three-dimensionality, spiro scaffolds have been shown indisputable promise as chemopreventive agents. A new series of heterocycles containing spirooxindole and pyrrolidine rings were synthesized by the 1,3-dipolar cycloaddition of an azomethine ylide, which was generated in situ by the condensation of a secondary amino acid ( l ‑proline) and dicarbonyl compounds (isatin), with dipolarophiles. This method is simple and provides diverse and biologically interesting products. The new series of compounds with a high degree of stereo- and regioselectivity were evaluated against breast cancer cell lines (MCF-7) and leukemia (K562). Among them, compound 4g was identified as the most potent with IC50 values of 15.49 ± 0.04 μM, against breast cancer cell lines (MCF-7) compared to standard drug 5-Fu (IC50 = 78.28 ± 0.2 μM) and compound 4i IC50 values of 13.38 ± 0.14 μM against leukemia (K562) compared to standard drug 5-fluorouracil (5-FU) (IC50 = 38.58 ± 0.02). The selective apoptotic effects of 4g were investigated against MCF-12 normal mammary cell and the cytotoxicity of 4g was not associated with any induction of necrosis compared to untreated cells. Molecular docking studies were investigated. From the docking data, these compounds could be act as small molecules that inhibit the MDM2-p53 interaction.

Glycosylation of 1,2-Dihydro-5-(1H-indol-2-yl)-1,2,4-triazole-3-thione with 2,3,4,6-tetra-O-acetyl-α-D-glucopyranosyl bromide, 2,3,4,6-tetra-O-acetyl-α-D-galactopyranosyl bromide and 2-acetamido-3,4,6-tri-O-acetyl-2-deoxy-α-D-glucopyranosyl chloride was investigated in the presence of Et₃N and K₂CO₃ as acid scavengers. A regioselective S-glycosides were obtained by using Et₃N whereas, using K₂CO₃ gave a mixtures of two hybrids having two glycosidic bonds. The two products of each mixture were separated and characterized as S,N(1)- and S,N(2)-bis(glycosylated) derivatives. The structures of the newly synthesized compounds were elucidated by (1)H NMR, (13)C NMR, 2D NMR and mass spectra. The compounds were screened for their antibacterial and antifungal activities. Some compounds exhibited strong inhibition activity compared with the reference drugs (chloramphenicol and baneocin).

Glycosylations of 5-(1H-indol-2-yl)-1,3,4-oxadiazoline-2(3H)-thione delivered various degrees of S- and/or N-glycosides depending on the reaction conditions. S-Glycosides were obtained regiospecifically by grinding oxadiazolinethiones with acylated α-D-glycosyl halides in basic alumina, whereas 3-N-(glycosyl)oxadiazolinethiones were selectively obtained by reaction with HgCl2 followed by heating the resultant chloromercuric salt with α-D-glycosyl halides in toluene under reflux. On using Et3N or K2CO3 as a base, mixtures of S- (major degree) and N-glycosides (minor degree) were obtained. Pure 3-N-(glycosyl)oxadiazolinethiones can also be selectively obtained from glycosylsulfanyloxadiazoles by the thermal S→N migration of the glycosyl moiety, which is proposed to occur by a tight-ion-pair mechanism. Thermal S→N migration of the glycosyl moiety can be used for purification of mixtures of S- or N-glycosides to obtain the pure N-glycosides. The aminolysis of the respective S- or N-glycosides with ammonia in aqueous methanol served as further confirmation of their structures. While in S-glycosides the glycosyl moiety was cleaved off again, 3-N-(glycosyl)oxadiazolinethiones showed a ring opening of the oxadiazoline ring (without affecting the glycosyl moiety) to give N-(glycosyl)thiosemicarbazides. Herewith, a new synthetic access to one of the four classes of glycosylthiosemicarbazides was found. The ultimate confirmation of new structures was achieved by X-ray crystallography. Finally, action of ammonia on benzylated 3-N-(galactosyl)oxadiazolinethione unexpectedly yielded 3-N-(galactosyl)triazolinethione. This represents a new path to the conversion of glycosyloxadiazolinethiones to new glycosyltriazolinethione nucleosides, which was until now unknown.

A new class of N-2-glycosyl thiosemicarbazides has been synthesized from N-3-glycosyl oxadiazoline-thiones. Glycosylation of 5-(1H-indol-2-yl)-1,3,4-oxadiazolin-2(3H)-thione with acetylated α-glycosyl halides by grinding in the presence of basic alumina gave the S-glycosyl oxadiazoles while in the presence of Hg(II) chloride N-3 glycosyl analogues were obtained. In the presence of Et 3 N or K 2 CO 3 , mixtures of S- and N-glycosylated isomers were obtained as products. The S→N glycosyl migration under catalyst-free mild thermal conditions was described, and a new class of N-2-glycosyl thiosemicarbazides was synthesized from N-3-glycosyl oxadiazolinethiones by ring cleavage of the oxadiazolole ring by treatment with ammonia in methanol.

The design and synthesis of six new receptors (R1–R6) and their anion sensing properties through multiple channels are reported. These receptors are constructed in such a way that they possess indole groups as the binding sites and different acceptors units of varying electron acceptor strengths. Receptors R1, R3 and R5 could recognize fluoride ions visually and spectroscopically with high selectivity over other anions in DMF, which was demonstrated by a visual detection experiment and UV-Vis, fluorescence and 1H NMR spectral studies. The remaining three receptors (R2, R4 and R6) exhibited colour changes with both fluoride and cyanide ions. The binding constants for fluoride binding by these receptors were determined to be in the order of 104 to 106 M−1 and found to depend on the electron accepting property of the acceptor unit in the intra molecular charge transfer (ICT) transition existing with the indole donor units. 1H NMR titration experiments not only provide evidence for the existence of H-bonding interactions between the indolic N–H groups of these receptors and F−, but also offer key insight into the strengths of the receptor–anion complexes of stoichiometry 1:2. The higher fluoride binding ability of the receptor containing the naphthoquinone signalling unit has been interpreted in terms of the greater electron deficiency of the acceptor unit (quinone) and enhanced H-bond donating character of the indole N–H group. The results of the electrochemical and DFT computation studies corroborate well with the spectroscopic studies.

We synthesized Phenyl-4-(2-phenylhydrazono) hexahydrofuro[3,2-c]pyridazin-7-ol (compound 3). The structure compound 3 was elucidated with IR, 1H NMR, 13C NMR and EIMS spectra. Compound 3 showed potent inhibitory activity against aspartic proteases, human cathepsin D and Plasmodium falciparum plasmepsin-II with IC50 = 20 μM. Enzyme-inhibitor complexes were predicted to stabilize by electrostatic and hydrophobic interactions between the side chains of amino acid residues at the active center and compound 3. Moreover, compound 3 displayed good nematocidal activity against all developmental stages of C. elegans.

The molecular complexes of novel water soluble 1,4-benzoquinones possessing different alkoxy substituents, with cimetidine drug have been investigated using various spectral techniques such as UV–Vis, 1H NMR, FT-IR. The stoichiometry of the CT complexes was found to be 1:1, in all the cases. The Density Functional Theory calculations supported the experimental observations. Correlation of formation constants (K) of the CT complexes with Taft’s polar (σ⁎) and steric (Es) constants indicated that an increase in electron releasing property of the alkoxy group makes these acceptors increasingly weaker while an increase in steric property of the substituent decreased the formation constant.

Three sets of substituted indolyl-triazoles were synthesized by the alkylation of 1,2-dihydro-5-(1H-indol-2-yl)-1,2,4-triazole-3-thione with different alkyl halides. The use of pyridine restricted the alkylation to sulfur. Whereas, upon using K2CO3, the alkylation exceeded sulfur to one of the remaining triazole nitrogens. The assignment of which nitrogen is alkylated besides sulfur is made for the first time using X-ray analysis of single crystals and 2D NMR which indicated that S-, 2-N-isomers will be preferably formed over the S-, 1-N-isomers. The antiproliferative activity on HEPG-2 and MCF-7 cancer cell lines was tested. The results showed that compound 2a is the most active with an IC50 3.58 μg/mL and 4.53 μg/mL for HEPG-2 and MCF-7 respectively and compound 7 is the least active with an IC50 > 100 μg/mL compared to the standard drug doxorubicin (IC50 4.0 μg/mL). The interaction of the synthesized compounds with tyrosine kinases, namely, Akt, PI3, and EGFR was also studied using molecular docking simulation to predict their mode of action which will drive future work directions.

The interaction of oxatomide (OXA), azacyclonol (AZA) and chloropheniramine (ClPA) antihistamine drugs with iodine was studied spectrophotometrically in different solvents and at three different temperatures. The electronic, FT-IR, far-IR, and mass spectra of the resulting charge-transfer (CT) complexes were recorded, in addition to thermal analysis. The results obtained show that the stoichiometries of the reactions are all 1:1. The observed time dependence of the CT band and subsequent formation of \( {\text{I}}_{3}^{ - } \) in solution were related to the slow transformation of the initially formed 1:1 (donor: I2) outer complex to an inner complex (electron donor–acceptor), followed by a fast reaction of the inner complex with iodine to form a triiodide ion. The characteristic strong absorptions of \( {\text{I}}_{3}^{ - } \) are observed around 360 nm. The CT-complexes have the formulae [(OXA)I]+\( {\text{I}}_{3}^{ - } \), [(AZA)I]+\( {\text{I}}_{3}^{ - } \) and [(ClPA)I]+\( {\text{I}}_{3}^{ - } \). The formation constants (K), molar absorption coefficients (eCT), and thermodynamic parameters ΔH#, ΔS# and ΔG# of these interaction have been determined and discussed.

The in vivo and in vitro effects of 4,5-diphenylimidazole-2-thione ( 1) , 4,5-Diphenyl-1,2,4-triazole-3-thiol ( 2 ) and 5-(2-Hydroxyphenyl)-4-phenyl-1,2,4-triazole-3-thiol ( 3 ) on α-glucosidase and α-amylase were investigated. The in vivo inhibition has been found to be dose-dependent and to occur at a value less than LD 50 . The in vitro treatment of the enzymes by 4,5-diphenylimidazole-2-thione exhibited a reversible inhibition of the non-competitive type with K i value of 3.5 and 6.5 × 10 −5 M for α-glucosidase and α-amylase, respectively. 4,5-Diphenyl-1,2,4-triazole-3-thione showed a reversible inhibition of the competitive and non-competitive types, with K i value of 10 −5 M magnitude, for α-glucosidase and α-amylase. On the other hand, 5-( o -hydroxyphenyl)-4-phenyl-1,2,4-triazole-3-thione did not display an inhibitory effect towards α-amylase but showed a potent inhibition of the competitive type for hepatic α-glucosidase with 10 −5 M magnitude of K i value.

Synthesis of {3-[1-(ethoxycarbonyl)-[1,2,4]triazolo[4,3-a]quinoxalin-4-yl]-1-phenyl-1H-pyrazol-5-yl}methyl ethyl oxalate (2), ethyl 4-[5-(acetoxymethyl)-1-phenyl-1H-pyrazol-3-yl]-[1,2,4]triazolo[4,3-a]quioxaline-1-carboxylate (4), [4-halo-1-phenyl-3-(1-phenyl-[1,2,4]triazolo[4,3-a]quioxalin-4-yl)-1H-pyrazol-5-yl]methyl acetate (11), {4-halo-3-[1-methyl-[1,2,4]triazolo[4,3-a]quinoxalin-4-yl]-1-phenyl-1H-pyraz-ol-5-yl}methyl acetate (13), and [3-([1,2,4]triazolo-[4,3-a]quinoxalin-4-yl)-4-halo-1-phenyl-1H-pyrazol-5-yl] methyl formate (15) was accomplished. The structural investigation of the new compounds is based on chemical and spectroscopic evidences. J. Heterocyclic Chem., (2011)

Reaction of pyridin-2(1H)-one 1 with 4-bromobutylacetate (2), (2-acetoxyethoxy)methyl bromide (3) gave the corresponding nicotinonitrile O-acyclonucleosides, 4 and 5, respectively. Deacetylation of 4 and 5 gave the corresponding deprotected acyclonucleosides 6 and 7, respectively. Treatment of pyridin-2(1H)-one 1 with 1,3-dichloropropan-2-ol (8), epichlorohydrin (10) and allyl bromide (12) gave the corresponding nicotinonitrile O-acyclonucleosides 9, 11, and 13, respectively. Furthermore, reaction of pyridin-2(1H)-one 1 with the propargyl bromide (14) gave the corresponding 2-O-propargyl derivative 15, which was reacted via [3+2] cycloaddition with 4-azidobutyl acetate (16) and [(2-acetoxyethoxy)methyl]azide (17) to give the corresponding 1,2,3-triazole derivatives 18 and 19, respectively. The structures of the new synthesized compounds were characterized by using IR, (1)H, (13)C NMR spectra, and microanalysis. Selected members of these compounds were screened for antibacterial activity.

The kinetics of cetyltrimethylammonium bromide stabilized silver nanoparticles was studied spectrophotometrically in the absence and presence of poly(vinyl alcohol) (PVA). Silver nanoparticles were prepared in aqueous solution using silver nitrate and cysteine as oxidant and reductant, respectively. Size and the distribution of the particles were determined by transmission electron microscopy. Silver nanoparticles were spherical, aggregated, cross-linking and of uniform particle size (the average particle size was about 30 and 7 nm in absence and presence of PVA, respectively). At higher concentration of PVA, the formation of silver sol was not observed for a certain reaction time, i.e., 200 min. Silver sol formation follows zero-order kinetics with respect to [Ag + ]. Viscosity of the CTAB-PVA mixture was also determined. A mechanism that involves simultaneous formation of cysteine–Ag complex has been proposed.

Six new thioglycosides incorporating the 4,5-diphenyl- and 3,4,5-triphenylimidazole moiety have been successfully synthesized under both conventional and microwave conditions by reaction of the corresponding thiones with aceto-bromosugars in presence of triethylamine as base. Attempted preparation of the bis(glycosyl) derivatives from 4,5-diphenylimidazole-2-thione in the presence of different bases was unsuccessful. Evaluation of the glycosylthioimidazoles as disarmed donors has been investigated using different promoters; NBS/TMSOTf has been found to be an effective promoter for the activation of the anomeric center towards glycosylation reaction.

Regioselective alkylation of 2-thiouracils 1a-c and 4-thiouracils 7a,b with 2,3-O-isopropylidene-2,3-dihydroxypropyl chloride (2) afforded 2-[[(2,2-Dimethyl-1,3-dioxolan-4-yl) methyl]thio]pyrimidin-4(1H)-ones 3a-c and 4-[[(2,2-Dimethyl-1,3-dioxolan-4-yl)methyl]thio] pyrimidin-2(1H)-ones 8a,b, respectively. Further alkylation with 2 and/or 2,3-O-isopropylidine-1-O-(4-toluenesulfonyl)-glycerol (4) gave the acyclo N-nucleosides 5a-c and 9a,b whose deprotection afforded 6a-c and 10a,b. 2-(Methylthio)pyrimidin-4(1H)-ones 11a-c and 4-(methylthio)pyrimidin-2(1H)-ones 14a,b were treated with 2 and/or 4 to give 12a-c and 15a,b which were deprotected to give 13a-c and 16a,b. Pyrimidine-2,4(1H,3H)-dithiones 17a-c were treated with two equivalents of 2 to give 2,4-bis[[(2,2-dimethyl-1,3-dioxolan-4-yl)methyl]thio] pyrimidines 18a-c. Deprotection of compounds 18a-c gave 2,4-bis[(2,3-dihydroxypropyl)thio]pyrimidines 19a-c. The activity of the deprotected nucleosides against Hepatitis B virus was evaluated and showed moderate inhibition activity against HBV with mild cytotoxicity.

The stereocontrolled syntheses of the β(1,2- cis )-rhamnosides via inter- and intramolecular glycosidation reactions, reductive cleavage of 4,6-acetals, inversion of α-rhamnosidic linkages and modification of β-mannosides have been reviewed. The report contains 88 references. Figure options Download full-size image Download as PowerPoint slide

A number of new N -arylaminomethyl-1,3,4 -oxadiazole derivatives 2, 3a,b, and 9-12a,b were prepared. Sugar (5-N-arylaminomethyl-l,3,4-oxadiazol-2-yl) hydrazones 4-6a,b were synthesized by the reaction of the hydrazino derivatives 3a,b with the corresponding monosaccharides. The novel acyclo-C-nucleosides 7, 8a,b were prepared by heterocyclization of the sugar hydrazones 4, 5a,b with acetic anhydride. A number of the synthesized compounds were tested for their antiviral activity against herpes simplex virus type-1 (HSV-1) and hepatitis-A virus (HAV, MBBcell culture-adapted strain). The results revealed that the sugar hydrazones 6a,b showed higher antiviral activity compared to the other hydrazones and their acetylated derivatives.

Alkylated, benzylated and bromoalkylated benzimidazole-thione that intramolecularly heterocyclized to 3,4-dihydro-2H-[1,3]thiazino[3,2-a]benzimidazole were synthesized. The chemical structure of the synthesized product was characterized by Infra Red, ¹H-NMR, (13)C-NMR, and Mass spectroscopy. Furthermore, the molecular structures of 8 and 9 were confirmed by X-ray single crystallography in different space groups, Pbca and P2₁/c, respectively.

Alkylation of 2-methylthiopyrimidin-4(1H)-one (1a) and its 5(6)-alkyl derivatives 1b-d as well as theophylline (7) with 2,2-bis(bromomethyl)-1,3-diacetoxypropane (2) under microwave irradiation gave the corresponding acyclonucleosides 1-[(3-acetoxy-2-acetoxymethyl-2-bromomethyl)prop-1-yl]-2-methyl-thio pyrmidin-4(1H)-ones 3a-d and 7-[(3-acetoxy-2-acetoxymethyl-2-bromomethyl)prop-1-yl]theophylline (8), which upon further irradiation gave the double-headed acyclonucleosides 1,1 '-[(2,2-diacetoxymethyl)-1,3-propylidene]-bis[(2-(methylthio)-pyrimidin-4(1H)-ones] 4a-c, and 7,7 '-[(2,2-diacetoxymethyl)-1,3-propylidene]-bis(theophylline) (9). The deacetylated derivatives were obtained by the action of sodium methoxide. The activity of deacetylated nucleosides against Hepatitis B virus was evaluated. Compound 5b showed moderate inhibition activity against HBV with mild cytotoxicity.

3-Thioxo-2H-imidazo[1,5-b]isoquinoline-1,5-dione (3) and 2-sub-stituted 3-thioxo-2H-imidazo[1,5-b]isoquinoline-1,5-diones (4a–l) were prepared from the reaction of 2-thiohydantoin (2) and 3-substituted 2-thiohydantoin (5a–l) with 2-formyl benzoic acid (1). Alkylation of 3 under an anhydrous basic conditions afforded 4a–i. The alkylation of 3 in aqueous basic solution afforded 3-(alkylmercapto)imidazo[1,5-b]isoquinoline-1,5-diones (7a,b). Reactions of the aromatic amino acids 9a,b and 12 with 7a afforded 2-(2H-1,5 dioxoimidazo[1,5-b]isoquinazolin-3-ylideneamino)benzoic acids (10a, b) and 3-(2H-1,5-dioxoimidazo[1,5-b]isoquinazolin-3-ylideneamino)2-naphthalenecarboxylic acid (13), which were then cyclyzed by heating in acetic anhydride to afford 15H-isoquino[2′,3′ :3,4] imidazo[2,1-b]quinazoline-7,13,15-triones (11a,b) and 14H-isoquino[2′,3′:3,4]imidazo[2,1-b]benzo[g]quinazoline-8,14,16-trione (14). Some of the new compounds were tested for their antitumor activities.

Comparison of the in vivo and in vitro effects of S -(2,3,4,6-tetra- O -acetyl-β- d -glucopyranosyl)thiuronium bromide ( 1 ), 2-(2,3,4,6-tetra- O -acetyl-β- d -glucopyranosylthio-1,3,4-thiadiazolin-5-thione ( 2 ), and 2-(2,3,4,6-tetra- O -acetyl-β- d -glucopyranosylthio)-1,3-benzoxazole ( 3 ), as well as the antidiabetics Daonil and insulin on glycosidase enzymes has been investigated. Compound 1 inhibited both α- and β-glucosidases, but the inhibition was more potent with the β-enzyme. Compound 2 was found to be a weaker inhibitor of these enzymes, while compound 3 showed a slight apparent activation.

The use of O-diphenylmethyl (DPM) and the O-(9-fluorenyl) (Fl) trichloroacetimidates permitted efficient protection of alcohols. The compatibility of these groups with other chemical manipulations is demonstrated. Glucosylation of typical acceptors with an O-glucopyranosyl trichloroacetimidate as donor having a DPM group at 2-O afforded β-glucopyranosides, thus demonstrating anchimeric assistance of the DPM group in the anomeric stereocontrol. This effect was also observed in mannopyranoside synthesis. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)

The in vivo and in vitro effects of 4-amino-3-(D-glucopentitol-1-yl)-5-mercapto-1,2,4-triazole and its 3-methyl analogue on alpha- and beta-glucosidases, beta-glucuronidase as well as alpha-amylase have been investigated. alpha-Glucosidase is the enzyme that is markedly affected in vivo and in vitro in a dose-dependent manner. The compounds showed a reversible inhibition of a competitive type for alpha-glucosidase. Moreover, they exert a relatively potent inhibition on alpha-glucosidase with a Ki magnitude of 3.6 x 10(-4), 9.5 x 10(-5) M.

A series of mannosyl donors linked via position 2 to an m-xylylene or an isophthaloyl spacer which was connected to the position 6 of a glucoside acceptor afforded, via intramolecular glycosylation, the corresponding disaccharides with high beta anomeric ratio.

Ethyl (benzimidazol-1-yl)acetate was subjected to hydrazinolysis with hydrazine hydrate to give (benzimidazol-1-yl)acetohydrazide. The latter was reacted with various aromatic aldehydes to give the respective arylidene (1H-benzimidazol-1-yl)acetohydrazones. Solutions of the prepared hydrazones were found to contain two geometric isomers. Similarly (2-methyl-benzimidazol-1-yl)acetohydrazide was reacted with various aldehydes to give the corresponding hydrazones. The antibacterial activity was evaluated in vitro by minimum inhibitory concentration (MIC) against Agrobacterium tumefaciens (A. tumefaciens), Erwinia carotovora (E. carotovora), Corynebacterium fascians (C. fascians) and Pseudomonas solanacearum (P. solanacearum). MIC result demonstrated that salicylaldehyde(1H-benzimidazol-1-yl)acetohydrazone (4) was the most active compound (MIC = 20, 35, 25 and 30 mg/L against A. tumefaciens, C. fascians, E. carotovora and P. solanacearum, respectively). Quantitative structure activity relationship (QSAR) investigation using Hansch analysis was applied to find out the correlation between antibacterial activity and physicochemical properties. Various physicochemical descriptors and experimentally determined MIC values for different microorganisms were used as independent and dependent variables, respectively. pMICs of the compounds exhibited good correlation (r = 0.983, 0.914, 0.960 and 0.958 for A. tumefaciens, C. fascians, E. carotovora and P. solanacearum, respectively) with the prediction made by the model. QSAR study revealed that the hydrophobic parameter (ClogP), the aqueous solubility (LogS), calculated molar refractivity, topological polar surface area and hydrogen bond acceptor were found to have overall significant correlation with antibacterial activity. The statistical results of training set, correlation coefficient (r and r 2), the ratio between regression and residual variances (f, Fisher’s statistic), the standard error of estimates and significant (s) gave reliability to the prediction of molecules with activity using QSAR models. However, QSAR equations derived for the MIC values against the tested bacteria showed negative contribution of molecular mass.

tert -Butyldimethylsilyl 3,6-di- O -benzyl-2-deoxy-2-dimethylmaleimido-β- d -glucopyranoside was readily transformed into the disaccharide glycosyl donor, 3,4,6-tri- O -acetyl-2-deoxy-2-dimethylmaleimido-β- d -glucopyranosyl-(1→4)-3,6-di- O -benzyl-2-deoxy-2-dimethylmaleimido-α/β- d -glucopyranosyl trichloroacetimidate, and the disaccharide glycosyl acceptor, tert -butyldimethylsilyl 3,6-di- O -benzyl-2-deoxy-2-dimethylmaleimido-β- d -glucopyranosyl-(1→4)-3,6-di- O -benzyl-2-deoxy-2-dimethylmaleimido-β- d -glucopyranoside. A TMSOTf-catalysed coupling of the acceptor with the donor afforded the respective tetrasaccharide derivative, which can be transformed to chitotetraose. tert -Butyldimethylsilyl 3,6-di- O -benzyl-2-deoxy-2-dimethylmaleimido-4- O -phenoxyacetyl-β- d -glucopyranosyl-(1→4)-3,6-di- O -benzyl-2-deoxy-2-dimethylmaleimido-β- d -glucopyranoside was converted into donor 3,6-di- O -benzyl-2-deoxy-2-dimethylmaleimido-4- O -phenoxyacetyl-β- d -glucopyranosyl-(1→4)-3,6-di- O -benzyl-2-deoxy-2-dimethylmaleimido-β- d -glucopyranosyl trichloroacetimidate. Its coupling with benzyl 3,6-di- O -benzyl-2-deoxy-2-dimethylmaleimido-β- d -glucopyranosyl-(1→4)-3,6-di- O -benzyl-2-deoxy-2-dimethylmaleimido-β- d -glucopyranoside, followed by dephenoxyacetylation, gave benzyl 3,6-di- O -benzyl-2-deoxy-2-dimethylmaleimido-β- d -glucopyranosyl-(1→4)-3,6-di- O -benzyl-2-deoxy-2-dimethylmaleimido-β- d -glucopyranosyl-(1→4)-3,6-di- O -benzyl-2-deoxy-2-dimethylmaleimido-β- d -glucopyranosyl-(1→4)-3,6-di- O -benzyl-2-deoxy-2-dimethylmaleimido-β- d -glucopyranoside, whose glycosylation furnished, after replacement of the DMM-group by the acetyl moiety and subsequent deprotection, chitohexaose.

The N-DMM-Protected lactosamine derivative 2 was readily transformed into the corresponding glycosyl donor 4 and into acceptor 5. A TMSOTf-catalyzed glycosidation afforded the derived tetrasaccharide 6 which led to glycosyl donor 9. Reaction of 9 with lactose derivative 10 as acceptor gave the desired hexasaccharide 11. Cleavage of all protective groups and N-acetylation afforded the target molecule 1b (lacto-N-neohexaose). Glycosylation of acceptor 10 with donor 4 furnished tetrasaccharide 16 which, employing standard procedures, gave acceptor 18. Glycosylation of 18 with donor 9 furnished, under standard conditions, octasaccharide 19. Cleavage of all protective groups and N-acetylation afforded the target molecule 1c (lacto-N-neooctaose). Both 1b and 1c were obtained in good overall yields.

Methyl 2,3,4-tri-O-acetyl-6-O-(p-tolylsulfonyl)-α-D-glucopyranoside (6), or its iodo analogue 7, were subjected to nucleophilic displacement with morpholine to give 8, deacetylation of which gave methyl 6-deoxy-6-(morpholin-4-yl)-α-D-glucopyranoside (3). Similarly, 11, 12 and 21 were prepared. The 6-deoxy-6-iodo derivative 16 was subjected to nucleophilic displacement with morpholine and subsequent acetylation to give 15. Deacetylation of 15 gave 17. The kinetic studies for the inhibition of β-D-glucosidase from sweet almond and using o-nitrophenyl β-D-glucopyranoside as substrate exhibited a K i value for 21 on the same order as 1-deoxynojirimycin whereas for 3, a K i value of lesser order was observed.

Reaction of benzamidrazone hydroiodide 1 with D-glucose 2, D-galactose 3 and D-arabinose 8 followed by acetylation afforded 1-(2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyl)-, 1-(2,3,5,6-tetra-O-acetyl-α-D-galactofuranosyl)- and 1-(1,2,3,4,5-penta-O-acetyl-D-manno-pentitol-1-yl)-5-methyl-3-phenyl-1H-1,2,4-triazole 6, 7 and 13, respectively. Structural analyses of these products were carried out by 1H, 13C, and 2D NMR spectra (DQFCOSY, HMQC and HMBC experiments), as well as by MS, FABMS and X-ray crystallography.

The sodium salts of some hetaryls of the quinoxalin-2-ones 2-4, phthalazine-1,4-dione 5, phthalazin-1-one 6, and pyridazin-6-ones 7 and 8 were alkylated with (+/-) 2,3-O-isopropylidene-1-O-(4-toluenesulfonyl)glycerol (1) to give the respective tetraseco-nucleosides 9-15. Their deisopropylidenation with 70% acetic acid in water gave the corresponding 2,3-dihydroxyprop-1-yl hetaryls 16-22. Compounds 16-22 showed varying inhibition activity against Hepatitis B virus (HBV) with low to moderate cytotoxicity, where 18 and 21 showed the highest replication inhibition and low cytotoxicity.

Reaction of D-erythro-2,3-hexodiulosono-1,4-lactone-2,3-bis(phenylhydrazone) (2) with an iodine, triphenylphosphine and imidazole mixture afforded the furo[3,2-c]pyridazine derivative 11. Condensation of 6-bromo-6-deoxy-D-erythro-2,3-hexodiulosono-1,4-lactone with phenylhydrazine gave the bishydrazones 6, and 8 or the furo[3,2-c]pyridazine (11) depending on the reaction conditions. The lactone ring in 11 could be opened by treatment with alkali to give the pyridazine derivative 9. Lactonization of the later with simultaneous acetylation by acetic anhydride afforded the lactone derivative 14. Alkali treatment of 6 gave the pyrazolindione derivative 13 that gave upon reation with HBr/AcO H the dibromide 15. The assigned structures were based on spectral analysis. The activity of compounds 11 and 14 against hepatitis B virus has been studied.

Glucosamine was readily transformed into N-dimethylmaleoyl (DMM) protected derivative 1 which furnished trichloroacetimidate 4 as glycosyl donor. Reaction with various acceptors (5a–g) in the presence of TMSOTf as the catalyst afforded the corresponding β-glycosides 6a–g generally in high yields. Cleavage of the DMM group was readily accomplished by treatment with aqueous NaOH and then with HCl (pH 5). Starting from 1 also DMM group containing glycosyl acceptors 9 and 14a–c were synthesized. They furnished with trichloroacetimidates 12 and 4 as glycosyl donors β(1-4)- and β(1-3)-linked disaccharides 13 and 15a–c, respectively. From 18 as galactosyl donor and 14a as acceptor β(1-3)-linked disaccharide 19 was obtained in high yield, which is a versatile building block for the important Galβ(1-3)GlcNAc unit. 19 was transformed into trichloroacetimidate 21; glycosylation with 5e as acceptor gave trisaccharide 22 which furnished on partial deprotection Galβ(1-3)GlcNAcβ(1-4)Glc derivative 24. Thus, the wide applicability of DMM as amino protective group in oligosaccharide synthesis is exhibited.

Cyclodehydrogenation of the ethylidene derivative of (5-methyl-1,2,4-triazino[5,6-b]indol-3-yl)hydrazine (1) gave the angular isomer, 1,10-dimethyl-1,2,4-triazolo[3′,4′:3,4][1,2,4]triazino[5,6-b]indole (4). The linear isomer, 3,10-dimethyl-1,2,4-triazolo[4′,3′:2,3][1,2,4]triazino[5,6-b]indole (7) could be prepared regioselectively by the cyclodehydration of the acetyl derivative of 1. The cyclodehydrogenation was extended to the monosaccharide derivatives of 1. The role of the N-methyl group on the site of annellation has been discussed.

Reaction of 6-aryl-5-cyano-2-thiouracils 2a-d with glycosyl halides 4a,b under alkaline conditions gave the respective bisglycosylated derivatives 5a-h. However, their deacetylation with ammonia in methanol caused a cleavage of the S-glycosyl residue and gave the N-3 glycosylated analogues 6a-h.

A series of 14 new 3-[4(3H)-quinazolinone-2-yl)thiomethyl]-1,2,4-triazoles were prepared and characterized by elemental analyses, IR, [ 1 H] NMR and mass spectral data. Four of the compounds showed insecticidal activity equivalent to that of malathion against the adult stage of the blow fly (Chrysomyia albiceps). However, their activity against the larval stages of this insect species was considerably weaker.

Charge-transfer molecular complexes of some 2-aryl-4-arylidene-5(4) oxazolanes with di- and trinitrobenzene have been studied at 25°C. The stoichiometry and apparent formation constants of the complexes formed were determined by applying the conventional continuous variation method. The role of the molecular structure of the electron donor and acceptor compounds as well as the nature of the solvent on the formation of such charge-transfer complexes. Furthermore, association constants, oscillator strength, dipole moment, and free energy are elucidated.

The isobutylidenation of 1-C- substituted l -threo-, d -erythro- glycerols , and d -arabino-tetritol has been studied. The location of the acetal could be adjusted by selecting the conditions for acetalation as well as the configuration of the polyol. The structure of the products was deduced by a combination of physical and chemical methods. The shift rule for the isopropylidene group has been extended to include the chemical shift difference of the two methyl groups of the isobutylidene rings.

The immunomodulating properties of functionalized [2-(arylamino)-4,4-dimethyl-6-oxo-cyclohex-1-ene] carbodithioates and 6,6-dimethyl-4-(2-(propan-2-ylidene)hydrazinyl)-6,7-dihydro-2H-indazole-3(5H)-thione compounds have been investigated. Four of them, 13, 18, 19 and 20 inhibited PBMC proliferation induced by phytohemagglutinin (PHA) in a dose dependent manner with an IC(50) of ≤ 20 μM. The Th-1 cytokine, interleukin-2 (IL-2) in PHA/PMA-stimulated peripheral blood mononuclear cells (PBMCs) is significantly inhibited by 13, 19 and 20 with an IC(50) of 8.4 ± 0.4, 5.34 ± 0.15 and 4.9 ± 0.7 μM, respectively. They also inhibited the PMA/lipopolysaccharide-induced proinflammatory cytokines, IL-1β and TNF-α production in human monocytic leukemia cells (THP-1), by 86%, 46% and 59.2% for IL-1β and by 83.8%, 48.2% and 58.7% for TNF-α, respectively. Only 20 showed significant suppressive activity against the phagocyte oxidative burst in a dose dependent manner, with an IC(50) of 23.8 μM. LPS-induced nitrites in mouse macrophages were found to be inhibited by compounds 6, 8, 13-15 and 19 with an IC(50), which range between 7.7 and 63 μM. The cytotoxicity for the active compounds was also studied on Rat Wistar Hepatocyte cell line, CC1 and the Mouse Fibroblast cell line 3T3 NIH in the presence of compounds using a standard MTT assay. Furthermore, structural-activity relationship using automated docking software revealed that active compounds 7, 13 and 19, adapted the same binding mode, however the most active compound 20 is found deeply inserted within the ligand binding site of IL-2, as multiple hydrophobic and hydrophilic key interactions stabilize the compound inside the binding site, thus contributing higher activity.

The 1H and 13C NMR spectra of sugar (5-methyl [1, 2, 4]-triazino [5, 6-b] indol-3-yl) hydrazones (1), per-0-acetyl aldehydo sugar 1-acetyl-1-(5-methyl [1, 2, 4] triazino [5, 6-b]-indol-3-yl) hydrazones (2), l- (penta-0-acetyl-pentitol-1-yl)-10-methyl [l, 2, 4] triazolo [3′, 4′:3, 4] [l, 2, 4] triazino [5, 6-b]-indoles (3) have been investigated. The 2 D NMR (H, C COSY) spectrum of 2a has been studied.

Oxidative cyclisation of the ethylidene derivatives of 5-allyl-3-hydrazino-1,2,4-triazino[5,6-b]indole (7) and 8-bromo-3-hydrazino-5H-1,2,4-triazino[5,6-b]indole (8) gave regioselectively the linear isomers, 10-allyl-3-methyl-1,2,4-triazolo[4′,3′:2,3][1,2,4]triazino[5,6-b]indole (15) and 7-bromo-3-methyl-10H-1,2,4-triazolo[4′,3′:2,3][1,2,4]triazino-[5,6-b]indole (16), respectively. They were also obtained by the dehydrative cyclisation of 5 and 6 respectively with acetic acid as well as by the condensation of the N-allyl- (22) or 5-bromo-isatin (23) with 3,4-diamino-5-methyl-4H-1,2,4-triazole (24). The corresponding allyl derivatives 17 and 18 were also synthesised. Some sugar derivatives of 5 were prepared.

Glycosylation of pyridinone (IV) under conventional or microwave-assisted conditions affords the corresponding O-glycosides instead of the N-glycosides.

13C NMR and 2D (H,H and H,C COSY) spectra of selected examples of sugar (5H-1,2,4-triazino[5,6-b]-indol-3-yl) hydrazones, peracetylated sugar-1-acetyl -1- (5-acetyl-1,2,4-triazino[5,6-b]indol-3-yl)hydrazones, and 10-acetyl-3-(per-0-acetylalditol-1-yl)-1,2,4-triazolo[4′, 3′:2,3][1,2,4]triazino[5,6-b]indole have been reported. The conformation of the latter C-nucleoside analogues have been determined by analysis of their 1H NMR spectra. The D-galacto, D-manno and L-arabino isomers are preponderantly existing in the planar zigzag arrangement of carbon atoms.