A. M. Shestopalov

N-Cyanochloroacetamidine — A convenient reagent for the regioselective synthesis of fused diaminopyrimidines

Abstract N-Cyanochloroacetamidin reacts wit conjugated thiolato(selenolato)nitriles to give product of regioselective S(Se) alkylation that can subsequently be involved in the Thorpe reaction. Resulting enaminocyanamidines form pyrimidine rings under acid or base catalysis forming fused diaminopyrimidines. According to this common scheme, functionally substituted thieno[3,2-d]pyrimidines, thiazolo[4,5-d]pyrimidines, pyrimido[4″,5″:4′,5′]thieno[3′,2′:4,5]thieno[3,2-d]pyrimidine, pyrido[3′,2′4,5]thieno(selenopheno)[3,2-d]pyrimidines, their hydrogenated analogues, and pyrimido-[4′,5′:4,5]thieno[2,3-d]pyrimidine were synthesized.

2-Bromo-1-arylethylidenemalononitriles — Convenient reagents for the regioselective synthesis of fused pyridines

Abstract 2-Bromo-1-arylethylidenemalononitriles react with conjugated thiolatonitriles to give products of regioselective S alkylation that can be subsequently involved in the Thorpe reaction. Resulting enaminoacrylonitriles form pyridine ring under base catalysis yielding thienodipyridines. According to this common scheme, functionally substituted thieno[3,2-b]pyridines, thiazolo[4,5-b]pyridines, thieno[3,2-b:4,5-b]dipyridines, their hydrogenated analogues, and pyrido[2′,3′:4,5]thieno[2,3-d]pyrimidine were synthesized.

Intramolecular cyclization of 2-(o-carboran-1-yl) methylthio-3-cyanopyridines in basic conditions

Substituted 2-(o-carboran-1-yl)methylthio-3-cyanopyridines and-pyrimidines undergo Thorpe-Ziegler cyclization under the influence of KOH in DMF to give the corresponding thienopyridines and thienopyrimidines. The reaction is complicated by a side reaction in which thecloso-carborane nucleus is converted to anido-system. The yield of thienopyridines containing acloso-carborane unit is increased by introduction of an acceptor substituent in the pyridine ring. Destruction of thecloso-carborane nucleus is not observed with the pyrimidine derivatives. The structures of the series of new carborane-containing thienopyridines and pyrimidines was confirmed by spectroscopic methods.

Single-step synthesis of substituted 7-aminopyrano[2,3-d]pyrimidines

A single-step method for the synthesis of substituted 7-aminopyrano[2,3-d]pyrimidines was developed. The method involves a three-component reaction of barbituric acid or 4,6-dihydroxypyrimidine with aromatic aldehydes and malononitrile in DMF in the presence of N-methylmorpholine as a catalyst.

New approaches to the synthesis of functionally substituted pyrido[3′,2′:4,5]thieno[3,2-b]pyridines and the structure of the products obtained

Substituted pyrido,[3,2:4,5]thieno[3,2-b]pyndines were obtained by the reaction of 3-amino-2-benzoylthieno [2,3-b]pyridines with malononitrile and the reaction of 3-cyanopyridine-2(IH)-thiones with 2-aryl-3-bromo-I,I-dicyanopropene. 2-Amino-4-(4-bromophenyl)-7, 9-dimethyl-3-cyanopyrido [3,2:4,5]thieno[3, 2-b]-pyridine was used for the synthesis of a derivative of pyrido[3,2:4, 5]thieno[2,3:5,6]pyrido[2,3-d]-pyrimidine. The structure of these compounds was confirmed by spectral data and x-ray diffraction structural analysis.

Regioselective synthesis of 5,6-polymethylene-3-cyanopyridine-2(1H)-thiones and fused heterocycles based on them

Condensation of 2-hydroxymethylenecyclopentan-1-one or -cyclooctan-1-one sodium salts with cyanothioacetamide afforded 5,6-polymethylene-3-cyanopyridine-2(1H)-thiones which were regioselectively alkylated at the sulfur atom by alkyl halides. Derivatives of 3-cyanopyridine-2(1H)-thione and 2-alkylthio-3-cyanopyridine were used for regioselective synthesis of substituted heterocycles: 3-aminothieno[2,3-b]pyridines, pyrido[2,3∶2′,3′]thieno[4,5-d]pyrimidines, and pyrido[2,3∶2′,3′]thieno[4,5-d]oxazines.

Nucleophilic substitution at α-methylene group attached to o-carboranes. Synthesis of carboranylmethylthiopyridines

Abstract The SN2-type substitution on bromomethyl-o-carborane was never reported earlier. It was found that pyridine-2(1H)-thiones react with bromomethyl-o-carborane in the presence of triethylamine. This reaction leads to the o-carboranylmethylthiopyridines with high yields. A series of the novel o-carboranylmethylthiopyridines was synthesized and characterized by various spectral methods.

REGIOSELECTIVE SYNTHESIS AND PROPERTIES OF 3-CYANO-6-THIENYLPYRIDINE-2(1H)-THIONES

Reactions of sodium derivatives of 2- and 3-thenoylacetaldehydes with cyanothioacetamide gave 2- and 3-cyano-6-thienylpyridine-2(1H)-thiones, which were used in the synthesis of substituted 2-alkylthiopyridines, thieno[2,3-b]pyridines, and other fused heterocycles.

Synthesis of 3-nitropyrid-2(1H)-ones fromC-nitroacetamide and 1,3-dicarbonyl compounds

The reaction of nitroacetamide with 1,3-dicarbonyl compounds afforded 3-nitropyrid-2(1H)-ones. The chemical reactivities of nitroacetamide and nitroacetohydrazide were compared.

Regioselective synthesis of substituted thieno[2,3-b]pyrimidines and pyrido[3′,2′:4,5]thienopyrimidines and their [3,2-d]selenopheno analogs from 3-cyanopyridine-2(1H)-thiones, 3-cyano-pyridine-2(1H)-selenones, and N-cyanochloracetamidine

Abstract3-Cyanopyridine-2(1H)-thiones and 3-cyano-2(1H)-selenones undergo heteroannelation with N-cyano-chloracetarnidine to give thieno[2, 3-b]pyridines,selenopheno[2, 3-b]pyridines, 2, 4-diantinopyrido-[3′, 2′:4, 5]thieno[3, 2-d]pyritnidines, and 2, 4-diamittopyrido[3′, 2′:4, 5]selenopheno[3, 2-d]pyritnidines, which were converted to compounds containing triazine, anzinopyrimidine, and pyrimidinedione rings.