Mannich reaction in the synthesis of N,S-containing heterocycles. 14*. Unexpected formation of thiazolo[3,2-a]pyridines in the aminoalkylation of N-methylmorpholinium 4-aryl-3-cyano-6-oxo-1,4,5,6-tetrahydropyridine-2-thiolates by isobutyraldehyde and primary amines

Treatment of N-methylmorpholinium 4-aryl-3-cyano-6-oxo-1,4,5,6-tetrahydropyridine-2-thiolates with an excess of isobutyraldehyde and primary aromatic amines in refluxing ethanol gives the corresponding 7-aryl-3-arylamino-2,2-dimethyl-5-oxo-2,3,6,7-tetrahydro-5 H-thiazolo[3,2-a]pyridine-8-carbonitriles in 18-38 % yields.     

Synthesis of thiazolo[3,2-a]pyridines via an unusual Mannich-type cyclization

The Mannich-type reaction of N-methylmorpholinium 4-aryl-3-cyano-6-oxo-1,4,5,6-tetrahydropyridine-2-thiolates with 3-(1,3-benzodioxol-5-yl)-2-methylpropanal (ocean propanal) and p-toluidine afforded 7-aryl-2-(1,3-benzodioxol-5-ylmethyl)-2-methyl-3-[(4-methylphenyl)amino]-5-oxo-2,3,6,7-tetrahydro-5H-thiazolo[3,2-a]pyridine-8-carbonitriles in modest (25–46%) yields. The structure of the key compound was confirmed by X-ray crystal structure analysis.     

A Double Mannich -type Reaction in the 1,4,5,6-Tetrahydropyridine-2-thiolate Series: A Convenient Approach to Functionalized 3,7-Diazabicyclo[3.3.1]nonane Derivatives

The reaction of N-methylmorpholinium 5-alkoxy-carbonyl-4-aryl-3-cyano-2-oxo-1,4,5,6-tetrahydropyridine-2-thiolates with primary amines and formaldehyde under mild conditions afforded 7-substituted alkyl 9-aryl-5-cyano-2-oxo-4-thioxo-3,7-diazabicyclo[3.3.1]nonane-1-carboxylates in fair to good yields (52–74%).     

A Double <Emphasis Type="Italic">Mannich</Emphasis>-type Reaction in the 1,4,5,6-Tetrahydropyridine-2-thiolate Series: A Convenient Approach to Functionalized 3,7-Diazabicyclo[3.3.1]nonane Derivatives

Summary. The reaction of N-methylmorpholinium 5-alkoxy-carbonyl-4-aryl-3-cyano-2-oxo-1,4,5,6-tetrahydropyridine-2-thiolates with primary amines and formaldehyde under mild conditions afforded 7-substituted alkyl 9-aryl-5-cyano-2-oxo-4-thioxo-3,7-diazabicyclo[3.3.1]nonane-1-carboxylates in fair to good yields (52–74%). Third author was Deceased on February 26, 2007     

Fused sulfur-containing pyridine systems. 1. Synthesis and structures of tetrahydropyridothienopyridinone and tetrahydropyridothiopyranopyridinone derivatives

The reactions of N-methylmorpholinium 4-aryl(hetaryl)-5-cyano-2-oxo-1,2,3,4-tetrahydropyridine-6-thiolates with malononitrile and acetone in ethanol afforded substituted tetrahydropyridothienopyridinones. In the absence of acetone, tetrahydropyridothiopyranopyridinones were isolated as the major reaction products. The latter were also synthesized independently by the reactions of the above-mentioned thiolates with 2-amino-1,1,3-tricyanopropene. The structure of 2,4-diamino-10-(2-chlorophenyl)-3-cyano-5-imino-8-oxo-7,8,9,10-tetrahydro-5H-pyrido[2",3":2,3]thiopyrano[4,5-b]pyridine was established by X-ray diffraction analysis.     

1-(Cyanoacetyl)-3,5-dimethylpyrazole as Active Methylene Compound in Hantzsch-type Pyridine Synthesis: A Convenient and Highly Effective Approach to 3,5-Dicyano-4-(het)aryl-6-oxo-1,4,5,6-tetrahydropyridine-2-thiolates

Summary. Reaction of 1-(cyanoacetyl)-3,5-dimethylpyrazole with (E)-2-cyano-3-(het)arylprop-2-enethioamides was used for the synthesis of N-methylmorpholinium 3,5-dicyano-4-(het)aryl-6-oxo-1,4,5,6-tetrahydropyridine-2-thiolates for the first time. The latter were also obtained in a multicomponent one-pot mode via the condensation of cyanothioacetamide with corresponding aldehydes and above 1-cyanoacetylpyrazole in the presence of N-methylmorpholine under mild conditions. Thiolates 1 exist as a pair of cis/trans-diastereomers in different ratios (from 3:4 to 2:1). Last author was Deceased on February 26, 2007     

Synthesis of 3-cyano-5-ethoxycarbonyl-6-hydroxypyridine-2-thiol derivatives

Ethyl ethoxymethylenemalonate reacts with cyanothioacetamide andN-methylmorpholine to giveN-methylmorpholinium 3-cyano-5-ethoxycarbonyl-6-oxopyridine-2-thiolate. Alkylation of the latter yieldsS-alkyl derivatives. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 196–197, January, 1999.     

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.     

The Mannich reaction in the synthesis of N,S-containing heterocycles 10. Recyclization of stable cyclic michael adducts,N-methylmorpholinium 6-R-6-hydroxy-1,4,5,6-tetrahydropyridine-2-thiolates,to pyrimido[4,3-b][1,3,5]thiadiazines under conditions of aminomethylation reaction

5-Substituted N-methylmorpholinium 4-aryl-6-R-3-cyano-6-hydroxy-1,4,5,6-tetrahydro-pyridine-2-thiolates upon the action of primary amines and HCHO in ethanol undergo recyclization to 3,7-disubstituted 8-aryl-3,4,7,8-tetrahydro-2H,6H-pyrimido[4,3-b][1,3,5]thiadiazine-9-carbonitriles in low yields (5–28%). The latter were also obtained by alternative method, viz., by sequential condensation of cyanothioacetamide with aromatic aldehydes, primary amines, and HCHO.     

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.     

Bis-adducts formed by nickel(II) and zinc(II) chelates of pyridine-2-(1H)thiones with nitrogen donors

Summary The bis-adducts formed by nickel(II) and zinc(II) chelates of 3-cyano-4-aryl-6-phenyl pyridine-2-(1H)thiones with pyridine and N-methylimidazole have been prepared and characterized by microelemental analyses, i.r., u.v., vis., and ¹Hn.m.r. spectra and magnetic measurements. Owing to Lewis acid-base interactions, the diamagnetic square planar nickel(II) or zinc(II) chelates interact with two molecules of pyridine or N-methylimidazole in the two axial positions forming the corresponding octahedral bis-adducts.     

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.     

The Synthesis of Cyclopenta[ c ]pyridine (2-Pyrindene) Derivatives

Ethyl 2-(N-morpholinyl)cyclopent-1-ene-1-carboxylate reacted smoothly with cyanothioacetamide to give morpholinium 4-cyano-1-oxo-2,5,6,7-tetrahydro-1H-cyclopenta[c]pyridine-3-thiolate; the former when treated with N-benzyl-α-chloroacetamide gave either a S-alkyl derivative or cyclopenta[d]thieno[2,3-b]pyridine, depending on the reaction conditions. Under Mannich-type aminomethylation with primary amines and formaldehyde the above thiolate afforded derivatives of the previously unknown heterocyclic system, cyclopenta[g]pyrido[2,1-b][1,3,5]thiadiazine in 81–90% yields.     

Synthesis and alkylation ofN-methylmorpholinium 6-amino-3,5-dicyano-4-methylpyridine-2-thiolate

The condensation of acetaldehyde with a twofold excess of cyanothioacetamide andN-methylmorpholine givesN-methylmorpholinium 6-amino-3,5-dicyano-4-methylpyridine-2-thiolate. This compound is also formed by recyclization of 2,6-diamino-3,5-dicyano-4-methyl-4H-thiopyran. From this pyridinethiolate, several substituted 2-alkylthiopyridines and 3,6-diamino-5-cyano-4-methyl-2-methoxycarbonylthieno[2,3-b]pyridine were obtained.     

Synthesis and alkylation of new functionally substituted 4,4-dimethylpiperidin-2-ones

The reaction of ethyl isopropylidenecyanoacetate with ethyl 3-amino-3-thioxopropanoate gave rise to ethyl 4,4-dimethyl-6-oxo-2-thioxo-5-cyanopiperidine-3-carboxylate whose alkylation provided ethyl 2-benzylsulfanyl-4,4-dimethyl-6-oxo-5-cyano-1,4,5,6-tetrahydropyridine-3-carboxylate, ethyl 5-benzyl-2-benzylsulfanyl-4,4-dimethyl-6-oxo-5-cyano-1,4,5,6-tetrahydropyridine-3-carboxylate, and ethyl 7,7-dimethyl-5-oxo-6-cyano-3,5,6,7-tetrahydro-2H-thiazolo[3,2-a]pyridine-8-carboxylate.     

Interaction of Alkyl 5,6-Dialkyl-2-amino-3-cyano-4-pyridinecarboxylates with O-Nucleophiles. Synthesis of 6,7-Dialkyl-4-amino-2,3-dihydro-1H-pyrrolo[3,4-c]pyridine-1,3-diones

The reaction of alkyl 5,6-dialkyl-2-amino-3-cyano-4-pyridinecarboxylates with certain O-nucleophiles was investigated, as a result of which 6,7-dialkyl-4-amino-2,3-dihydro-1H-pyrrolo[3,4-c]pyridine-1,3-diones were synthesized.     

Synthesis of Azo-Sulfa Drugs Based on 2-Pyridinone and 2-Pyridinethione

Some new azo sulfa drugs 3-cyano-4,6-diphenyl-1-[4-(N-substituted)sulfamyl]phenylazo-2-pyridinone dyes (1-6) and 3-cyano-4,6-diphenyl-1-[4-(N-substituted)sulfamyl]phenylazo-2-pyridinethione dyes (1′-6′) were synthesized by coupling of 4-(N-substituted)sulfamylbenzene diazonium salts with 3-cyano-4,6-diphenyl-2-pyridinone and/or with 3-cyano-4,6-diphenyl-2-pyridin-ethione. The corresponding iron (1a-6a, 1′a-6′a), copper (1b-6b, 1′b-6′b) and mercury (1c-6c, 1′c-6′c) chelates wvere also prepared. All synthesized compounds were screened in vitro for antibacterial and antifungal activities.     

Reactions of 2-amino-, 2-alkylamino-, and 2-piperidino-1-azaazulenes with aryl and chlorosulfonyl isocyanates

Reaction of 2-amino-1-azaazulene with phenyl isocyanate gave 3-phenyl-2H-3,4-dihydro-1,3,4a-triazabenz[5,4-a]azulene-2,4-dione. Reactions of 2-alkylamino-1-azaazulenes with aryl isocyanates gave 2-(N-ethyl-N′-arylureido)-1-azaazulenes initially, which rearranged to N-aryl-2-alkylamino-1-azaazulene-3-carboxamides and successive reaction with another molar amount of aryl isocyanate furnished uracil-fuzed 1-azaazulenes. Reaction of 2-piperidino-1-azaazulene with aryl isocyanate gave N-aryl-2-piperidino-1-azaazulene-3-carboxamide. Reaction of 2-(substituted amino)-1-azaazulenes with chlorosulfonyl isocyanate gave 3-cyano- and 3-chloro-2-(substituted amino)-1-azaazulenes.     

The Synthesis of Cyclopenta[<Emphasis Type="Italic">c</Emphasis>]pyridine (2-Pyrindene) Derivatives

Summary. Ethyl 2-(N-morpholinyl)cyclopent-1-ene-1-carboxylate reacted smoothly with cyanothioacetamide to give morpholinium 4-cyano-1-oxo-2,5,6,7-tetrahydro-1H-cyclopenta[c]pyridine-3-thiolate; the former when treated with N-benzyl-α-chloroacetamide gave either a S-alkyl derivative or cyclopenta[d]thieno[2,3-b]pyridine, depending on the reaction conditions. Under Mannich-type aminomethylation with primary amines and formaldehyde the above thiolate afforded derivatives of the previously unknown heterocyclic system, cyclopenta[g]pyrido[2,1-b][1,3,5]thiadiazine in 81–90% yields. Victor P. Litvinov, was Deceased Victor P. Litvinov, This paper is dedicated to the blessed memory of our colleague, Prof. Victor Petrovich Litvinov (Dec 24, 1932–Feb 26, 2007)     

Competing processes in condensation of 3,3-bis(methylthio)-2-cyano-<Emphasis Type="Italic">N</Emphasis>-arylacrylamides with cyanoacetanilides

Reaction of cyanoacetanilides with 3,3-bis(methylthio)-2-cyano-N-arylacrylamides proceeds to form isomeric N,1-diaryl-1,6-dihydropyridine-3-carboxamides. A single crystal consisting of 2-amino-4-methylthio-N-(2-methoxyphenyl)-6-oxo-1-phenyl-5-cyano-1,6-dihydropyridine-3-carboxamide and 2-amino-4-methylthio-1-(2-methoxyphenyl)-6-oxo-N-phenyl-5-cyano-1,6-dihydropyridine-3-carboxamide was studied by XRD.