Stereoselective synthesis and tautomeric conversions of pyridyl-substituted 3,4-trans-1,2,3,4-tetrahydropyridines

Condensation of pyridinium ylides with pyridylmethylenecyanoacetic ester or pyridylmethylenecyanothioacetamide proceeds stereoselectively to form substituted 4-pyridyl-3-(1-pyridinio)-3,4-trans-1,2,3,4-tetrahydropyridine-6-(olates)thiolates. Substituted 2-(oxo)thio-4-(4-pyridyl)-3-(1-pyridinio)-3,4-trans-1,2,3,4-tetrahydropyridine-6-(olates)thiolates in DMSO-d₆ solution exist in tautomeric equilibrium with 4-(4-pyridinio)-3-(1-pyridinio)-1,4-dihydropyridine-2,6-(diolates)-dithiolates.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1630–1637, July, 1991.     

N-Methylmorpholinium 4-aryl-5-cyano-3-methoxycarbonyl-2-oxo-1,2,3,4-tetrahydropyridine-6-thiolates: synthesis and properties

Reactions of aromatic aldehydes with cyanothioacetamide and dimethyl malonate in the presence ofN-methylmorpholine affordedN-methylmorpholinium 4-aryl-5-cyano-3-methoxycarbonyl-2-oxo-1,2,3,4-tetrahydropyridine-6-thiolates. The latter were used to synthesize substituted 6-(alkylthio)-2-oxo-1,2,3,4-tetrahydropyridines. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 485–487, March, 2000.     

Synthesis, properties, and structures of ammonium 4-aryl-5-cyano-2-oxo-1,2,3,4-tetrahydropyridine-6-thiolates

The reaction of arylcyanomethylenethiocetamides with Meldrum, acid gave Michael adducts as ammonium salts. When heated in alcohol, these salts undergo cyclization to ammonium 4-aryl-5-cyano-2-oxo-1,2,3,4-tetrahydropyridine-6-thiolates. The structure ofN-methylmorpholinium 4-(2′-chlorophenyl)-5-cyano-2-oxo-1,2,3,4-tetrahydropyridine-6-thiolate was established by X-ray structural analysis. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1029–1034, May, 1997.     

Stereoselective synthesis of and atropisomerism in 4-pyridyl-3-(1-pyridinio)-3,4-trans-1,2,3,4-tetrahydropyridines and their transformation products

A series of 2-oxo-4-pyridyl-3-(1-pyridinio)-5-cyano-3,4-trans-1,2,3,4-tetrahydropyridine-6-6-olates were prepared by condensation of pyridinium ylides with α,β-unsaturated carbonyl compounds or more conveniently by a three-component condensation of pyridinium ylides, pyridine aldehydes, and ethyl cyanoacetate 3 and/or 6 . This analogues of the above tetrahydropyridines were prepared in a similar way starting from suitable substrates. Spectroscopic data revealed that the reaction leads to trans-isomers around the C³-C⁴ bond and is atroposelective. The conformation of and tautomerism in the tetrahydropyridines are discussed in the light of ¹H NMR data. The reaction of 5-cyano-3-(3-methyl-1-pyridinio)-2-oxo-4-(3-pyridyl)-1,2,3,4-tetrahydropyridine-6-thiolate 10c with phenacyl bromide was found to give 3-hydroxy-5-oxo-7-(3-pyridyl)-6-(3-methyl-1-pyridinio)-3-phenyl-8-cyano-6,7-trans-2,3,6,7-tetrahydrothiazol[3,2a]pyridine bromide, the crystal and molecular structure of which has been determined by X-ray crystallographic analysis.     

A new method for the synthesis ofN-methylmorpholinium 4-aryl-5-cyano-2-oxo-1,2,3,4-tetrahydropyridine-6-thiolates and their properties

N-Methylmorpholinium 4-aryl-5-cyano-2-oxo-2-oxo-1,2,3,4-tetrahydropyridine-6-thiolates were obtained by the condensation of aromatic aldehydes, cyanothioacetamide, and Meldrum's acid in the presence ofN-methylmorpholine. They were then used in the syntheses of substituted 6-alkylthio-3,4-dihydropyridin-2(1H)-ones and 4,5-dihydrothieno[2,3-b]pyridin-6(7H)-ones. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1852–1856, October, 1997.     

Synthesis and alkylation ofN-methylmorpholinium 5-cyano-4-(3- and 4-hydroxyphenyl)-2-oxo-1,2,3,4-tetrahydropyridine-6-thiolates

The reactions of 3- or 4-hydroxybenzaldehydes with cyanothioacetamide and Meldrum's acid in the presence ofN-methylmorpholine affordedN-methylmorpholinium 5-cyano-4-(3-or 4-hydroxyphenyl)-2-oxo-1,2,3,4-tetrahydropyridine-6-thiolates, respectively. The resulting compounds were used in the synthesis of substituted 6-alkylthio-1,2,3,4-tetrahydropyridin-2-ones. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2333–2336. December, 1999.     

Stereoselective synthesis and structure of 3,4-trans-6-amino-4-aryl-3-carbamoyl-5-cyano-1,2,3,4-tetrahydropyridin-2(1H)-thiones

Condensation of thiocarbamoylacetamide with arylidenemalononitrile or the three-component condensation of thiocarbamoylacetamide with aldehydes and malononitrile in the presence of triethylamine occurred regioselectively to give triethylammonium-6-amino-4-aryl-3-carbamoyl-5-cyano-1,4-dihydropyridine-2-thiolates. Protonation of the latter occurred stereoselectively to give 3,4-trans-6-aryl-3-carbamoyl-5-cyano-1,2,3,4-tetrahydropyridin-2(1H)-thiones. The¹H NMR spectrum and single x-ray crystallography indicate that the dihydropyridine ring has he sofa conformation with trans-pseudodiaxial orientation of the Ar and CONH₂ groups and trans-pseudoequatorial orientation of atoms 3-H and 4-H.N. D. Zelinskii Organic Chemistry Institute, Russian Academy of Sciences, Moscow, 117913. A. N. Nesmeyanov Institute of Elementoorganic Chemistry, Russian Academy of Sciences, Moscow, 117813. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1376–1382, Octoberm 1996. Original article submitted June 10, 1996.     

Reaction of ethyl 4-aryl-6-bromomethyl-2-oxo-1,2,3,4-tetrahydropyrimidine-5-carboxylates with N-methylmorpholinium 3-cyano-1,4-dihydro- and 3-cyano-1,4,5,6-tetrahydropyridine-2-thiolates

Alkylation of N-methylmorpholinium 4-Ar¹-3-cyano-6-oxo-1,4,5,6-tetrahydropyridine-2-thiolates using ethyl 4-Ar-6-bromomethyl-2-oxo-1,2,3,4-tetrahydropyrimidine-5-carboxylates (10 % KOH, DMF) gives mixtures of diastereomers of ethyl 4-Ar-6-[(4-Ar¹-3-cyano-1,4,5,6-tetrahydropyridin-2-ylthio)methyl]-1-methyl-2-oxo-1,2,3,4-tetrahydropyrimidine-5-carboxylates in overall 30-58 % yield. Under these conditions the N-methylmorpholinium 4-Ar1-5-(N-Ar²-carbamoyl)-3-cyano-6-methyl-1,4-dihydropyridine-2-thiolates undergo aromatization of the dihydropyridine ring to give ethyl 4-Ar-6-[4-Ar¹-5-(N-Ar²-carbamoyl)-3-cyano-6-methylpyridin-2-ylthio)methyl]-2-oxo-1,2,3,4-tetrahydropyrimidine-5-carboxylates (37-51 %). In the absence of KOH, only the substituted pyridine-2(1 H)-thione is formed as a product of oxidation of the dihydropyridine ring in the starting substrate. Some of the alkylation products obtained possess weak or moderate antibacterial activity towards the specific strains of Escherichia coli and Bacillus subtilis but are inactive towards Candida albicans and Staphylococcus aureus.     

Stereoselective synthesis of 3-mono- and 1,3-disubstituted 4-phenyl-1,2,3,4-tetrahydroisoquinolines

(1S,2S)-(+)-Thiomicamine was transformed in high yield and with high diastereoselectivity into (3R,4R)-4-phenyl-1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid and enantiomerically pure (3R,4R)-3-hydroxymethyl-4-phenyl- and (1R,3R,4R)-3-hydroxymethyl-1-methyl-4-phenyl-1,2,3,4-tetrahydroisoquinoline derivatives.     

Structure of 4-amino-6-phenyl-5-cyano-2-cyclohexanespiro-1,3-dithia-4-cyclohexene and its recyclization to 5,6-tetramethylene-4-phenyl-3-cyano-2[1H]pyridinethione

Conclusions An intramolecular conformationally-rigid conjugation system was found in 4-amino-6-phenyl-5-cyano-2-cyclohexanespiro-1,3-dithia-4-cyclohexene. A probable mechanism for recyclization to the corresponding 2(1H)-pyridinethione was proposed on the basis of the geometrical parameters.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1768–1774, August, 1985.     

Stereoselective synthesis of highly substituted tetrahydrofuran derivatives via Huisgen 1,3-dipolar cycloaddition of acyclic carbonyl ylides to activated styrenes

Stereoselective synthesis of highly functionalized tetrahydrofurans via the 1,3-dipolar cycloaddition reaction of acyclic carbonyl ylides to activated alkenes is described.     

Stereoselective synthesis of 3,4-disubstituted pyroglutamates by ring transformation of 5-ylidene-1,3-dioxan-4-ones with N-(diphenylmethylene)-glycinate

N-(Diphenylmethylene)-glycinate gives stereoselective conjugate addition to readily available (E) and (Z)-5-ylidene-1,3-dioxan-4-ones. Hydrolytic cleavage of the imine functionality of the resulting Michael-adducts causes ring transformation to new, optically active 3,4-disubstituted pyroglutamates.     

Synthesis and Crystal Structure of Ethyl 4-(3,4-Methylenedioxylphenyl)-6-methyl-2-oxo-1,2,3,4-tetrahydropyridine-5-carboxylate under Microwave Irradiation

<正>The crystal structure of the title compound (C16H17NO5) has been determined by single-crystal X-ray diffraction. The crystal is of monoclinic, space group C2/c with a = 18.520(2), b = 7.8910(1), c = 21.728(3) A, β = 104.77(1)°, V= 3070.4(7) A3, Mr= 303.31, Z = 8, Dc= 1.312 g/cm3, λ = 0.71073 A,μ(MoKα) = 0.098 mm-1 and F(000) = 1280. The structure was refined to R = 0.0486 and wR = 0.1287. There exist intermolecular hydrogen bonds in the crystal.     

Reaction of dichlorocarbene with substituted 3,4-dihydroisoquinolines and 1-methylene-1,2,3,4-tetrahydroisoquinolines

Reaction of dichlorocarbene with 3,3-dialkyl-3,4-dihydroisoquinolines results in the formation of gemdichloroazirino[2,1-a]isoquinolines, which are in turn converted to 3-benzazepinones upon hydrolysis. Reaction of dichlorocarbene with the ethyl ester or amide of (3,3-dimethyl-1,2,3,4-tetrahydroisoquinolin-1-ylidene)acetic acid is accompanied by rearrangement of the intermediate carbene adducts at the enamine C=C bond and results in the formation of a 1-azadiene, 3-(3,3-dimethyl-3,4-dihydroisoquinolin-1-yl)-3-chloroacrylic acid ethyl ester, and a spirolactam, 3,3-dimethyl-3-chlorospiro[1,2,3,4-tetrahydroisoquinoline-1,2-pyrrole]-5(2H)-one, respectively.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1086–1091, August, 1990.     

Synthesis of substituted 4-oxo-2-thioxo-1,2,3,4-tetrahydroquinazolines and 4-oxo-3,4-dihydroquinazoline-2-thioles

We have developed a liquid-phase synthesis of combinatorial libraries of new disubstituted 4-oxo-2-thioxo-1,2,3,4-tetrahydroquinazolines and trisubstituted 4-oxo-3,4-dihydroquinazoline-2-thioles. The former were prepared using two general procedures: (i) cyclization of substituted methyl anthranilates with isothiocyanates, or (ii) cyclization of substituted 2-(methylcarboxy)benzeneisothiocyanates with primary amines or hydrazines. 4-Oxo-3,4-dihydroquinazoline-2-thioles were prepared by S-alkylation of disubstituted 4-oxo-2-thioxo-1,2,3,4-tetrahydroquinazolines with alkyl or aryl halides. The hydrolysis of methyl benzimidazo[1,2-c]quinazoline-6(5H)-thione-3-carboxylate led to the corresponding acid. This acid was utilized in the synthesis of new benzimidazo[1,2-c]quinazoline-6(5H)-thione-3-carboxamide and S-substituted 6-mecaptobenzimidazo[1,2-c]quinazoline-3-carboxamide libraries.     

Synthesis and Properties of Ammonium 5-Benzoyl-4-(2-chlorophenyl)-3-cyano-6-hydroxy-6-phenyl-1,4,5,6-tetrahydropyridine-2-thiolates

The reaction of 2-chlorobenzaldehyde with cyanothioacetamide and dibenzoylmethane in the presence of piperidine or N-methylmorpholine gave the corresponding 5-benzoyl-4-(2-chlorophenyl)-3-cyano-6-hydroxy-6-phenyl-1,4,5,6-tetrahydropyridine-2-thiolates, used in the synthesis of 1-alkylthio-4-benzoyl-1-benzoylamino-3-(2-chlorophenyl)-2-cyanobut-1-enes.     

Synthesis and Crystal Structure of 3-Carbamoyl-6-methyl-5-phenylcarbamoyl-2-thioxo-1,2,3,4-tetrahydropyridine-4-spirocyclohexane

3-Carbamoyl-6-methyl-5-phenylcarbamoyl-2-thioxo-1,2,3,4-tetrahydropyridine-4-spirocyclohexane has been synthesized by the condensation of cyclohexylidenecyanothioacetamide with acetoacetanilide and piperidine. The structure of the product was established by X-ray structural analysis.     

Studies on enaminonitriles: A new synthesis of 1,3‐substituted pyrazole‐4‐carbonitrile

3‐Diethylaminoacrylonitrile ( 1 ) reacts with hydrazonyl halides ( 2a‐d ) to yield 1,3‐disubstituted pyrazole‐4‐carbonitriles 5a‐d. The acetyl 1‐p‐chlorophenylpyrazole‐4‐carbonitrile ( 5a ) condensed with hydrazine hydrate to yield the bishydrazone 10 and with dimethylformamide dimethylacetal to yield 1‐aryl‐3‐(3‐dimethylamino)acryloyl pyrazole‐4‐carbonitrile ( 11 ). This enamine reacts with hydrazine hydrate to yield the pyrazolylpyrazole ( 12 ) and with naphthoquinone to yield the 3‐naphthofuranoyl pyrazole 13. The pyra‐zolyl pyridine derivative 14 was obtained upon treatment of 11 with acetylacetone in the presence of ammonium acetate. Compound 11 was coupled with p‐chlorobenzene diazonium chloride to yield the hydrazone 16 that was coupled further with p‐chlorobenzenediazonium chloride to yield the formazane 18.     

Stereoselective one-pot synthesis of substituted (4Z)-2-alkyl-4-benzylidene- 4H-1,3-benzothiazines

Substituted (4Z)-4-benzylidene-2-methyl-4H-1,3-benzothiazines (1). and (4Z)-2-ethyl-4-benzylidene-4H-1,3-benzothiazines (2). were synthesized by direct stereoselective reactions of S-phenyl ethanethioate or S-phenyl propanethioate with substituted benzyl nitriles in the presence of triflic anhydride.