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A preparative method for the synthesis of optically pure N-(1-phenylethyl)amides of inherently chiral (cR)- and (cS)-dibenzoyloxy-calix[4]arene acetic acids has been developed. Their absolute stereochemical configuration was determined by X-ray diffraction analysis.

A method for the synthesis of aminomethyl-substituted five-membered sultams has been developed. The aminomethyl sultams were synthesized from the corresponding iodomethyl derivatives by nucleophilic substitution of the iodine atom with sodium azide followed by reduction on Pd/C. This method was further expanded to side-chain-substituted sultams, starting from amino acid esters, to obtain aminomethyl-containing bicycles. The simple practical procedure and available starting amino acid esters, including chiral examples, make various bicyclic sultams readily available.

The cyclization of di-(2,6-difluorophenyl)maleindinitrile with magnesium(II) and zinc(II) acetates in boiling ethylene glycol is applied to synthesize Mg(II) and Zn(II) complexes of the octa-(2,6-difluorophenyl)tetraazaporphyrin. The compounds are identified by UV–Vis, 1H NMR, and mass spectrometry methods. A comparative analysis is performed of the spectral-luminescent properties of magnesium and zinc octaaryltetraazaporphyrinates and their dependence on the number and position of the fluorine atoms in the macrocycle phenyl fragments. The DFT method is used to optimize the geometry of the synthesized complexes. Machine learning methods and QSPR are applied to predict the Soret band wavelength in the UV–V is spectra of the complexes described.

A regioselective method for the synthesis of 1-(hydroxymethyl)-2,3-dihydropyrrolo[1,2-a]quinazolin-5(1H)-ones – close structural analogs of naturally occurring vasicinone alkaloids – is described. The procedure is based on PIFA-initiated oxidative 5-exo-trig cyclization of 2-(3-butenyl)quinazolin-4(3Н)-ones, in turn prepared by thermal cyclocondensation of the corresponding 2-(pent-4-enamido)benzamides. The products obtained have a good natural product likeness (NPL) score and therefore can be useful for the design of natural product-like compound libraries.

A preparatively convenient one-pot method for the synthesis of new 7-thioxo[1,3]thiazolo[3,2-c]pyrimidine derivatives 3a–3l by the cyclocondensation of 5-methyl(1,3-thiazolidin-2-ylidene)ketones 1a...

5-Chloro-4-formylpyrrole-3-carboxylates react with anilines or β-naphthylamine when heated in DMF under reflux to form ethyl pyrrolo[2,3-b]quinoline-3-carboxylates or their benzo[f] analogs, which exhibit moderate fluorescent properties. The corresponding carboxylic acids were obtained by alkaline hydrolysis of the synthesized carboxylates.

A method for the preparation of chromeno[3,4-b]pyrrol-4(3H)-ones via the synthesis of the corresponding 3-arylpyrrole-2-carboxylates from pseudonitrosites by the Barton–Zard reaction was developed. As a result of selective O-demethylation upon exposure to BBr3, the lactone ring closes with the formation of substituted chromeno[3,4-b]pyrrolones in moderate yields.

Trianionic polymethines of the A'-π-A-π-A-π-A' type comprising dioxaborine rings (A) and different electron-accepting end groups (A') have been synthesized. The obtained dyes absorb and emit light in the near-infrared region with remarkably high molar attenuation coefficients (ϵ up to 495 000 M

A spectrophotometric study of the solubilization and aggregation of the Nile red dye (NR) in premicellar and micellar aqueous solutions of sodium dodecyl sulfate (SDS) was carried out. The experiments were conducted both with saturated solutions of NR under conditions of thermodynamic equilibrium of the solution with a dye precipitate, and at a constant concentration of NR in a homogeneous solution. In the first case, it was proved theoretically and verified experimentally that with an increase in the SDS concentration, the NR concentration always increases, and at the limit of low concentrations, the dependence is linear. In both cases, the concentration of NR dimers as a function passes through a maximum in the premicellar region. There are no dimers in the micellar region. The extinction coefficients of NR monomers in SDS solutions were determined both below and above the critical micelle concentration (CMC) of SDS. A solubilization curve with branches for the premicellar and micellar regions was constructed, the intersection of which was used to find the CMC value in the system under study. The state of deep supersaturation of the NR solution in the metastable state upon dilution of the micellar system with water was studied. It was found that, in addition to dimers, molecular aggregates of higher orders were also formed.

All four possible stereoisomers of cis- and trans-2-bromo-2,3-dihydro-1H-inden-1-ols, which are important intermediates in the synthesis of biologically active compounds, were synthesized and their configurations were studied by enzymatic kinetic resolution with the application of the Kazlauskas rule, X-ray diffraction analysis, as well as NMR using NOE-NMR and Karplus equation. Biocatalytic kinetic trans-esterification was used for resolution of racemates. Lipases Burkholderia cepacia and Candida Antarctica B (Novozyme 435) were effective as biocatalysts for biocatalytic esterification of 2-bromo-2,3-dihydro-1H-inden-1-ols with isopropylidene acetate. The absolute configurations of (S,S)-, (R,R)-, (S,R)- and (R,S)-stereoisomers of 2-bromo-2,3-dihydro-1H-inden-1-ols were established.

The convenient and scalable preparative approach for the two-step α-methylation of ketones is described. The optimized protocols for regioselective preparation of enaminones with further diastereoselective and functional groups tolerant hydrogenation to α-methylketones are developed. The scope and limitations of the proposed methodology are discussed. The advantages compared to known procedures are demonstrated. The unexpected role of acetone in the hydrogenation is suggested. The evaluation of the method for both early building block synthesis and late-stage CH-functionalization is shown. The elaborate procedures' preparability and scalability are demonstrated by the synthesis of several α-methyl ketones up to 100 g amount.

Cycloaddition reactions of 3,3,3-trifluoropropene derivatives containing an alkoxycarbonyl, sulfonyl, sulfoximine, or sulfamide substituent in position 1 with ethyl isocyanoacetate proceed with the formation of 3-(trifluoromethyl)-2,3-dihydro-1H-pyrroles, whereas their reactions with tosylmethyl isocyanide lead to the formation of 4-(trifluoromethyl)-1H-pyrroles.

[2,3,7,8,12,13,17,18-Octabromo-5,10,15,20-tetrakis(2,6-difluorophenyl)porphyrinato]zinc(II) was synthesized by reaction of [5,10,15,20-tetrakis(2,6-difluorophenyl)porphyrinato]zinc(II) with N-bromosuccinimide in chloroform–methanol, chloroform–dimethylformamide, and dimethylformamide. The reaction of [5,10,15,20-tetrakis(2,6-difluorophenyl)porphyrinato]zinc(II) with N-chlorosuccinimide in chloroform–methanol or dimethylformamide gave [2,3,7,8,12,13,17,18-octachloro-5,10,15,20-tetrakis(2,6-difluorophenyl)porphyrinato]zinc(II). [2,3,7,8,12,13,17,18-Octachloro-5,10,15,20-tetrakis(2,3,4,5,6-pentafluorophenyl)porphyrinato]zinc(II) was obtained by chlorination of [5,10,15,20-tetrakis(2,3,4,5,6-pentafluorophenyl)porphyrinato]zinc(II) with excess N-chlorosuccinimide in dimethylformamide. The synthesized complexes were identified by electronic absorption spectroscopy, 1H NMR, and mass spectrometry.

A practical divergent synthetic approach is reported for the library of regio- and stereoisomers of glutamic acid analogs built on the spiro[3.3]heptane scaffold. Formation of the spirocyclic scaffold was achieved starting from a common precursor – an O-silylated 2-(hydroxymethyl)cyclobutanone derivative. Its olefination required using the titanium-based Tebbe protocol since the standard Wittig reaction did not work with this particular substrate. The construction of the second cyclobutane ring of the spirocyclic system was achieved through either subsequent dichloroketene addition or Meinwald oxirane rearrangement as the key synthetic steps, depending on the substitution patterns in the target compounds (1,6- or 1,5-, respectively). Further modified Strecker reaction of the resulting racemic spirocyclic ketones with the Ellman’s sulfinamide as a chiral auxiliary had low to moderate diastereoselectivity; nevertheless, all stereoisomers were isolated in pure form via chromatographic separation, and their absolute configuration was confirmed by X-ray crystallography. Members of the library were tested for the inhibitory activity against H. pylori glutamate racemase.

(5-Methyl-1,3-thiazolidin-2-ylidene) ketones, depending on the substituent in the ylidene part of the molecule, interact with tosyl azide to form (5,6-dihydro[1,3]thiazolo[3,2-c][1,2,3]triazol-3-yl) ketones and N-[(5,6-dihydro[1,3]thiazolo[3,2-c][1,2,3]triazol-3-yl)alkylidene]-tosylamides.

We found that 1-phosphanyl-1,2,3,4-tetrahydroquinazolines undergo ring enlargement. Their treatment with trifluoroacetic or hydrochloric acid afforded diazaphosphepinium salts. Deprotonation of the...

A method for the synthesis of iodomethyl-substituted five-membered sultams has been developed. The sultams were synthesized by intramolecular iodoamination of alkenyl sulfamides. The method allows synthesis of N- and C-substituted sultams. NH-Sultams were prepared by acidic cleavage of the corresponding tert-butyl sultams that are readily available. Varying the length of alkenyl substituent at sulfamide it was shown that only five- and six-membered sultams could be prepared by this method. Neither four- nor seven-membered sultams were detected. The simple practical procedure and available starting materials make the variously substituted sultams readily available.

[2,3,7,8,12,13,17,18-Octabromo-5,10,15,20-tetrakis(2,6-dichlorophenyl)porphyrinato]zinc(II) and [2,3,7,8,12,13,17,18-octachloro-5,10,15,20-tetrakis(2,6-dichlorophenyl)porphyrinato]zinc(II) were synthesized by halogenation of [5,10,15,20-tetrakis(2,6-dichlorophenyl)porphyrinato]zinc(II) with N-bromosuccinimide and N-chlorosuccinimide, respectively, in a mixture of chloroform with methanol. Treatment of the halogenated zinc porphyrins with trifluoroacetic acid in chloroform gave the corresponding free ligands. The isolated compounds were identified by electronic absorption, 1H NMR, and mass spectra. The acid–base properties of 5,10,15,20-tetrakis(2,6-dichlorophenyl)porphyrin, 2,3,7,8,12,13,17,18-octabromo-5,10,15,20-tetrakis(2,6-dichlorophenyl)porphyrin, and 2,3,7,8,12,13,17,18-octachloro-5,10,15,20-tetrakis(2,6-dichlorophenyl)porphyrin were studied in acetonitrile at 298 K. Their acidity and basicity constants and concentration ranges of their ionized forms were determined.

Dichlorophosphoranides featuring N,N-dimethyl-N′-arylformamidine substituents were isolated as individual compounds. Dichlorophosphoranide 9 was prepared by the multicomponent reaction of C-trimethylsilyl-N,N-dimethyl-N′-phenylformamidine and N,N-dimethyl-N′-phenylformamidine with phosphorus trichloride. Its molecular structure derived from a single-crystal X-ray diffraction was compared to the analogous dibromophosphoranide prepared previously by us by the reaction of phosphorus tribromide with N,N-dimethyl-N′-phenylformamidine. It was shown that a chlorophosphine featuring two N,N-dimethyl-N′-mesitylformamidine substituents reacted with hydrogen chloride to form dichlorophosphoranide 11. Its molecular structure was also determined by X-ray analysis and compared with that of closely related dichlorophosphoranide C.

5-Substituted (1,3-thiazolidin-2-ylidene)ketones react regioselectively with 1-chlorobenzyl isocyanates under mild conditions to form diastereomeric 8-acyl-2,3,6,7-tetrahydro-5H-[1,3]thiazolo[3,2-c]pyrimidin-5-ones, the relative configuration of the chiral centers of which was determined by X-ray structural analysis.

The development of new functional materials based on porphyrins requires fast and accurate prediction of their spectral properties. The available models in the literature for absorption wavelength and extinction coefficient of the Soret band have low accuracy for this class of compounds. We collected spectral data for porphyrins to extend the literature set and compared the performance of global and local models for their modelling using different machine learning methods. Interestingly, extension of the public database contributed models with lower accuracies compared to the models, which we built using porphyrins only. The later model calculated acceptable RMSE = 2.61 for prediction of the absorption band of 335 porphyrins synthesized in our laboratory, but had a low accuracy (RMSE = 0.52) for extinction coefficient. A development of models using only compounds from our laboratory significantly decreased errors for these compounds (RMSE = 0.5 and 0.042 for absorption band and extinction coefficient, respectively), but limited their applicability only to these homologous series. When developing models, one should clearly keep in mind their potential use and select a strategy that could contribute the most accurate predictions for the target application. The models and data are publicly available.

Using DFT and ab initio calculations, we demonstrate that noncyclic formamidines can undergo thermal rearrangement into their isomeric aminocarbenes under rather mild conditions. We synthesized the silylformamidine, for which the lowest activation energy in this process was predicted. Experimental studies proved it to serve as a very reactive nucleophilic carbene. The reactions with acetylenes, benzenes, and trifluoromethane proceeded via insertion into sp, sp

The [1,2,3]triazin-4(3H)-one ring is a synthetically important molecular platform for a variety of chemical transformations. Despite this, currently, there has been little research on the reaction of the thermal opening of the [1,2,3]triazin-4(3H)-one nucleus. In this work, we describe the synthetic potential of anthra[1,2-d][1,2,3]triazine-4,7,12(3H)-trione in the reaction of the thermal opening of a cycle following the [4+2]-cycloaddition reaction with a number of pyridine derivatives and quinoline. It is shown that this method is effective for the synthesis of the 6H-naphtho[2,3-H]pyrido(quinolino)[2,1-b]quinazoline-6,9,14-trione system. We also investigate the influence of the position of substituents in the structure of pyridine on the formation characteristics of the target products.

A general approach to bicyclic fused pyrrolidines via [3 + 2]-cycloaddition between nonstabilized azomethyne ylide and endocyclic electron-deficient alkenes was elaborated. "Push-pull" alkenes and CF3-alkenes did not react with the azomethyne ylide under the previously reported conditions, and we developed a superior protocol (LiF, 140 °C, no solvent). Among obtained products were medchem-relevant bicyclic sulfones, monofluoro-, difluoro-, and trifluoromethyl-substituted pyrrolidines. This approach not only allowed preparation of novel molecules but also significantly simplified synthesis of the existing ones (e.g., sofinicline).

A regioselective method for the synthesis of 1-(hydroxymethyl)-2,3-dihydropyrrolo[1,2-a]quinazolin-5(1H)-ones – close structural analogs of naturally occurring vasicinone alkaloids – is described. The procedure is based on PIFA-initiated oxidative 5-exo-trig cyclization of 2-(3-butenyl)quinazolin-4(3Н)-ones, in turn prepared by thermal cyclocondensation of the corresponding 2-(pent-4-enamido)benzamides. The products obtained have a good natural product likeness (NPL) score and therefore can be useful for the design of natural product-like compound libraries.

The third generation Buchwald precatalysts Pd(ABP)(Phos)(OMs) (also known as Phos Pd G3)) with XPhos and RuPhos were prepared in multigram scale by a modified procedure (ABP = fragment of C-deprotonated 2-aminobiphenyl, XPhos = 2-dicyclohexylphosphino-2′,4′,6′-triisopropylbiphenyl, RuPhos = 2-dicyclohexylphosphino-2′,6′-diisopropoxybiphenyl, OMs− = CH3SO3−). The 1H- and 31P-NMR spectra of the title complexes and some impurities, measured by various 1D and 2D techniques, were analyzed in detail. The solvent-dependent isomerization of Pd(ABP)(XPhos)(OMs) was studied by NMR, and the X-ray structures of two isomers were determined. The impurities in precatalysts, such as Pd(ABP)(HABP)(OMs) (HABP—neutral 2-aminobiphenyl coordinated to Pd2+ in N-monodentate mode) and PdCl2(XPhos)2, were identified and characterized by single crystal X-ray diffraction. A simple method for the quick quality control (QC) of the precatalysts, suitable for routine use, was proposed. The method was based on the assessment of the impurity content on the basis of the 1H-NMR spectra analysis.

The reactions of diazomethane with bis(2-fluoro-2-polyfluoroalkylalkenyl) sulfones are accompanied by dehydrofluorination and lead to the formation of new dipyrazolyl sulfones containing polyfluoroalkyl substituents at position 4 of the pyrazole ring. The structure of four new sulfones was confirmed by X-ray diffraction analysis.