A. I. Vas’kevich

Intramolecular electrophilic cyclization of functional derivatives of unsaturated compounds: III. Reaction of N,4-Diarylbut-3-enamides with arenesulfenyl chlorides. Synthesis of 5-aryl-4-arylsulfanyl-2,3,4,5-tetrahydro-1H-1-benzazepin-2-ones

N-Aryl-4-phenylbut-3-enamides reacted with arenesulfenyl chlorides in chloroform to give N,4-diaryl-3-arylsulfanyl-4-chlorobutanamides, whereas in acetic acid in the presence of lithium perchlorate N-[4-arylsulfanyl-5-phenyltetrahydrofuran-2-ylidene]arenaminium perchlorates were obtained. Reactions of arenesulfenyl chlorides with N,4-diarylbut-3-enamides having strong electron-donating groups in positions 3 and 4 of the N-aryl substituent afforded 5-aryl-4-arylsulfanyl-2,3,4,5-tetrahydro-1H-1-benzazepin-2-ones.

Intramolecular electrophilic cyclization of functional derivatives of unsaturated Compounds: I. Synthesis of 5-arylsulfanyl-6-phenylpiperidin-2-ones from cinnamylacetamides and arylsulfenyl chlorides

Sterically nonhindered N-alkyl(aryl)amides of cinnamylacetic acid in the reaction with phenyl(4-tolyl)sulfenyl chlorides in acetic acid in the presence of lithium perchlorate undergo a selective cyclization into 5-arylsulfanyl-6-phenylpiperidin-2-ones. Under similar conditions the reaction with arylsulfenyl chlorides of amides containing bulky substituents at the nitrogen atom resulted in 5-arylsulfanyl-6-phenyltetrahydropyran-2-iminium perchlorates, which by treatment with aqueous ethanol were converted into the corresponding derivatives of pyran-2-ones.

Electrophilic intramolecular cyclization of functional derivatives of unsaturated compounds: V. Cyclization of anilides of styrylacetic acids in polyphosphoric acid

Anilides of styrylacetic acids at heating in polyphosphoric acid undergo an intramolecular cyclization giving 1,5-diarylpyrrolidin-2-ones, 5-aryl-1,3,4,5-tetrahydro-2H-benzazepin-2-ones, and 5-(3-fluorophenyl) dihydrofuran-2(3H)-one, where the ratio of the products depends on the character of the aromatic substituents in the amide and styrene fragments of the substrate.

Intramolecular electrophilic cyclization of functional derivatives of unsaturated compounds: II. Synthesis and transformation of N-{(2Z)-5-[(arylsulfanyl)methyl]dihydrofuran-2(3H)-ylidene}-N-alkyl(aryl)aminium perchlorates

N-Alkyl(aryl)amides of allylacetic acid when reacting with arylsulfenyl chlorides in acetic acid in the presence of lithium perchlorate undergo a selective cyclization to form N-{(2Z)-5-[(arylsulfanyl)methyl] dihydrofuran-2(3H)-ylidene}-N-alkyl-(aryl)aminium perchlorates. Treating of the latter with sodium acetate leads to the formation of the corresponding 5-[(arylsulfanyl)methyl]lactones, and with sodium ethylate, to 5-[(arylsulfanyl) methyl]-2-iminolactones. In reaction with secondary cycloalkylamines in the presence of water a transamidation and tetrahydrofuran ring opening occurs to afford 5-arylsulfanyl-4-hydroxypentanoic acid amides.

Cyclofunctionalization of 6-alkenylsulfanylpyrazolo[3,4-d]-pyrimidin-4(5H)-ones with arenesulfenyl chlorides

Reactions of 6-allylsulfanylpyrazolo[3,4-d]pyrimidin-4(5H)-one with arenesulfenyl chlorides in chloroform gave products of addition of the latter at the exocyclic double bond, while analogous reactions in acetic acid in the presence of LiClO4 were accompanied by intramolecular electrophilic cyclization involving the N7 atom. 6-Cinnamylsulfanylpyrazolo[3,4-d]pyrimidin-4(5H)-one reacted with arenesulfenyl chlorides in acetic acid in the absence of electrolyte to produce fused pyrazolo[4′,3′: 5,6]pyrimido[2,1-b][1,3]thiazine derivatives. Introduction of a bulky phenyl group into position 1 of the pyrazolo[3,4-d]pyrimidine system reduces the yield of the corresponding intramolecular cyclization product at N7 as a result of concurrent formation of acyclic addition product. DOI

Reactions of 2-(2-propynylsulfanyl)-5,6,7,8-tetrahydrobenzo[b]thieno[2,3-d] pyrimidin-4(3H)-one with arylsulfenyl chlorides

Abstract2-(2-propynylsulfanyl)-5,6,7,8-tetrahydrobenzo[b]thieno[2,3-d]pyrimidin-4(3H)-one with arylsulfenyl chlorides in chloroform gave products of anti-Markownikoff AdE-addition. The use of nitromethane as solvent in the presence of lithium perchlorate additives favored intramolecular electrophilic cyclization into 1-arylsulfanyl-1,2,6,7,8,9-hexahydro-4H-benzo[4,5]thieno[3,2-e][1,3]thiazolo[3,2-a]-pyrimidin-5-one.

Electrophilic cyclization of N-allyl(propargyl)-5-amino-1H-pyrazole-4-carboxamides. Synthesis of 4-[(dihydro)oxazol-2-yl]-1H-pyrazol-5-amines

N-Allyl-5-amino-1H-pyrazole-4-carboxamides in reactions with polyphosphoric acid, with N-halosuccinimides in chloroform, and with (chlorosulfanyl)benzenes in nitromethane in the presence of lithium perchlorate underwent cyclization involving the N-allylamide fragment to give 4-[5-methyl(halomethyl)-4,5-dihydrooxazol-2-yl]-1H-pyrazol-5-amines and 2-(5-amino-1H-pyrazol-4-yl)-5-[(arylsulfanyl)methyl]-4,5-dihydro-1,3-oxazolium perchlorates, respectively. Analogous reactions of N-propargyl-5-amino-1H-pyrazole-4-carboxamides with polyphosphoric acid afforded 4-(5-methyloxazol-2-yl)-1H-pyrazol-5-amines, and with (chlorosulfanyl) benzenes, 2-(5-amino-1H-pyrazol-4-yl)-5-[(arylsulfanyl)methylidene]-4,5-dihydro-1,3-oxazolium perchlorates.

Synthesis of 7-iodo(arylsulfanyl)methyl-7,8-dihydro-[1,3]thiazolo[2,3-i]purinium pentaiodide (perchlorates) and their transformation into 4-amino-5-(1,3-thiazol-2-yl)imidazole derivatives

Intramolecular electrophilic cyclization of 6-allylsulfanylpurine by the action of iodine and arenesulfenyl chlorides gave 7-iodomethyl-7,8-dihydro[1,3]thiazolo[2,3-i]purin-6-ium pentaiodide and 7-arylsulfanylmethyl-7,8-dihydro[1,3]thiazolo[2,3-i]purin-6-ium perchlorates, respectively. 7-Iodomethyl-7,8-dihydro-[1,3]thiazolo[2,3-i]purin-6-ium iodide reacted with sodium and potassium alkoxides to produce alkyl N-[5-(4-methyl-1,3-thiazol-2-yl)-1H-imidazol-4-yl]formimidates, and its reaction with secondary cyclic amines afforded 5-(4-methyl-1,3-thiazol-2-yl)-N-[morpholin-4-yl(or piperidin-1-yl)methylidene]-1H-imidazol-4-amines. Successive treatment of 7-arylsulfanylmethyl-7,8-dihydro[1,3]thiazolo[2,3-i]purin-6-ium perchlorates with sodium acetate and morpholine led to the formation of 5-(4-arylsulfanylmethyl-4,5-dihydro-1,3-thiazol-2-yl)-N-(morpholin-4-ylmethylidene)-1H-imidazol-4-amines.

Fused pyrimidine systems: XVII. Arylsulfenylation of 5-allylpyrimidine-4(3 H )-one derivatives. Synthesis of arylsulfanyl-substituted 5,6-dihydrofuro[2,3- d ]- and 6,7-dihydro-5 H -pyrano[2,3- d ]pyrimidines

Abstract5-Allylpyrimidine-4-ones react with arylsulfenyl chlorides in dichloromethane with the formation of 5-[(2-arylsulfanyl)-3-chloropropyl]-pyrimidine-4-ones that under the action of sodium acetate undergo cyclization into 6-arylsulfanyl-6,7-dihydro-5H-pyrano[2,3-d]pyrimidines. At performing similar reactions in nitromethane an intramolecular electrophilic cyclization occurs affording 6-[(arylsulfanyl)methyl]-5,6-dihydrofuro[2,3-d]pyrimidines.

Electrophilic intramolecular cyclization of functional derivatives of unsaturated compounds: IV. Cyclosulfenylation of 5-hexenoic acid amides and nucleophilic cleavage of reaction products

Anilides of 5-hexenoic acid react with arylsulfenyl chlorides in nitromethane in the presence of lithium perchlorate affording products of electrophilic cyclization, N-{6-[(arylsulfanyl)methyl]tetrahydro-2H-pyran-2-ylidene}anilinium perchlorates. The treatment of the latter with sodium acetate or secondary cycloalkylamines in the presence of water results in the opening of the tetrahydropyran ring and provides anilides or cycloalkylamides of 6-arylsulfanyl-5-hydroxyhexanoic acid.