Synthesis and Crystal Structure of 3-Ethoxycarbonyl-4,6-diphenyl-3,4-dihydropyridine-2(1H)-thione

3-Ethoxycarbonyl-4,6-diphenyl-3,4-dihydropyridine-2(1H)-thione was synthesized by the interaction of benzylideneacetophenone with cyanoacetic ester and hydrogen sulfide. Its structure was investigated by X-ray structural analysis. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1180–1183, August, 2005.     

Annelated tricyclic thiophenes and their photophysical properties

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THE EFFECT OF ACIDS ON THE INFRARED SPECTRA OF SCHIFF BASES—II. IMINES CONTAINING THE C=C-C=N AND C=C-C=C-C=N UNITS

Abstract— The Fourier-transform infrared spectra of chloroform-d solutions of conjugated imines CH₃CH=CHCH=NCH(CH₃)₂ and CH₃CH₂CH=CHCH=CHCH=NCH(CH₃)₂ and the related protonated species with HCl, HBr, HI, trichloro, dichloro, monobromo and monochloroacetic acids or propionic acid are presented. The effects of conjugation and protonation are examined. The results show that conjugation slightly increases the basicity of the Schiff bases. HCl, HBr and HI protonate the Schiff bases completely. The carboxylic acids protonate partially depending on their p K _a, values. When the Schiff base contains two (or more) C=C bonds conjugated with C=N, the main C=C stretching band undergoes a strong intensification showing that sizeable dipole moment variations occur along the conjugated chain.     

Synthesis of α-(4-hydroxyphenyl)-β,β,β-trifluoro-α-alanine derivatives

2,6-Dimethyl- and 2,6-dimethoxy-α-methoxycarbonyl-α-trifluoromethyl-p-methylenequinones have been synthesized. These compounds easily react with ammonia, morpholine, andp-toluidine to afford the corresponding α-(4-hydroxyphenyl)-β,β,β-trifluoro-α-alanine derivatives.     

Isopropylidenemalononitrile in the synthesis of 2-amino-4,6,6-trimethylcyclohexa-2,4-diene-1,1,3-tricarbonitrile, 6-amino-2-(4-methoxybenzoylmethylsulfanyl)-4,4-dimethyl-1,4-dihydropyridine-3,5-dicarbonitrile, and fused 2-aminopyrans according to Michael

Michael reactions of isopropylidenemalononitrile with cyanothioacetamide (in the presence of 4-methoxyphenacyl bromide), cyclohexane-1,3-dione, and 4-hydroxycoumarin, gave 6-amino-2-(4-methoxy-benzoylmethylsulfanyl)-4,4-dimethyl-1,4-dihydropyridine-3,5-dicarbonitrile, 2-amino-4,4-dimethyl-5-oxo-5,6,7,8-tetrahydro-4H-chromene-3-carbonitrile, and 2-amino-4,4-dimethyl-5-oxo-4H,5H-pyrano[3,2-c]-chromene-3-carbonitrile, respectively. In the reaction of isopropylidenemalononitrile with cyanoacetamide, only dimerization product of the former, 2-amino-4,6,6-trimethylcyclohexa-2,4-diene-1,1,3-tricarbonitrile, was isolated. Its structure was proved by X-ray analysis.     

Asymmetric nitrogen−35 : Structure and properties of l(s)-α-carboxyethyl-3, 3-bis(trifluoromethyl)diaziridine and its derivatives

A second-kind asymmetric transformation involving N-atom inversion has been observed at 20° for 1(S) - α - carboxyethyl - 3,3 - bis(trifluoromethyl)diaziridine 1 and its methyl ester 2. X-Ray data for the diastereomer (1S, 2S, α-S), 1A (which is thermodynamically preferred in the crystalline phase), ¹H NMR spectra of ethyl ester 3-¹⁵N(1) and 3-¹⁵N(2), CD spectra of 1A,B, 2A,B, potassium salt 4A,B and semiempirical calculations (MINDO/3 and INDO) for 1A, show that the stereospecificity of crystallization of the diastereomer A is due to the higher energy of the crystal lattice of the diastereomer (1R, 2R, α-S), 1B because of hindered charge compensation as well as to the hindrance by the CF₃, groups to intermolecular H-bonds. According to semiempirical calculations, the stability of 3,3 - bis(trifluoromethyl) - diaziridines (TFD) to the action ofel w-orbital energies and depolarization of the C-N bonds due to hyperconjugation and the inductive effect of the CF₃,-groups. The steric effect of these groups is the reason of the low configurational stability of TFD compared with the 3,3-dimethyl analogues.     

Reactions of polyfluorocarbonyl compounds with phenolates

Conclusions Hexafluoroacetone and methyl trifluoropyruvate react under mild conditions with sodium phenolate, sodium alkoxyphenolates, sodium alkylphenolates, and sodium dialkylphenolates to give the ortho-alkylation and ortho,ortho-dialkylation products. In the case of sodium phenolate, the tri-C-alkylation product is also obtained. The second C-alkylation of meta-substituted sodium phenolates was found to be difficult.For previous communication, see ref. [1].Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2849–2852, December, 1987.     

A New Route to Partially Hydrogenated Thiazolo[3,2-a]pyridine

Partially hydrogenated thiazolo[3,2-a]pyridines have been synthesized by the interaction of functionally substituted ammonium di- and tetrahydropyridine-2-thiolates with bromocyclohexanone. The structure of 6,8-dicyano-3-hydroxy-5-oxo-1,3-tetramethylene-2,3,4,5,6,7-hexahydrospiro[thiazolo[3,2-a]pyridine-7,1'-(4'-methylcyclohexane)] has been determined by X-ray crystallography.     

Single stage synthesis of 2-alkylthio(seleno)-4-hetaryl-3-cyano-5,6,7,8-tetrahydroquinolines

Reaction of N-(1-cyclohexenyl)morpholine, hetarylmethylenecyanothio(seleno)acetamides, and alkyl halides gives 2-alkylthio(seleno)-4-hetaryl-3-cyano-5,6,7,8-tetrahydrothieno[2,3-b]quinolines.T. G. Shevchenko State University, Lugansk 348011. N. D. Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, Moscow 117913. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1384–1390, October, 1997.     

Preparation of substituted 3-hydroxy-3-trifluoromethyl-2(3H)benzofuranones

Conclusions When heated with methyl trifluoropyruvate in aprotic solvents and acetic acid above 120°C it was found that phenols (not containing electron acceptor ring substituents) regioselectively formed ortho-C-alkylation products which could be lactonized to 3-hydroxy-3-trifluoromethyl-2(3H)benzo[b]furanones.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2511–2517, November, 1987.