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The acylation of pyridin-2-amine with furan-2-carbonyl chloride in propan-2-ol gave N-(pyridin-2-yl)furan-2-carboxamide, and treatment of the latter with excess P2S5 in anhydrous toluene afforded the corre-sponding carbothioamide which was oxidized with potassium ferricyanide in alkaline medium to 2-(furan-2-yl)-[1,3]thiazolo[4,5-b]pyridine. The product was subjected to electrophilic substitution reactions such as nitration, bromination, hydroxymethylation, formylation, and acylation, where the substituent entered exclusively the 5-position of the furan ring. The alkylation of the title compound with methyl iodide led to the formation of quaternization product at the pyridine nitrogen atom, whereas no amination according to Chichibabin was observed. [ABSTRACT FROM AUTHOR]

Acylation of 1,3-benzothiazol-6-amine with furan-2-carbonyl chloride in propan-2-ol gave N-(1,3-benzothiazol-6-yl)furan-2-carboxamide which was converted to the corresponding thioamide by treat-ment with excess P2S5 in anhydrous toluene. The subsequent oxidation with potassium hexacyanoferrate(III) in alkaline medium afforded 2-(furan-2-yl)benzo[1,2-d:4,3-d′]bis[1,3]thiazole which was subjected to electrophilic substitution reactions (bromination, nitration, hydroxymethylation, formylation, acylation). The substituent entered exclusively into the 5-position of the furan ring. [ABSTRACT FROM AUTHOR]

Condensation of 1-aminonaphthalene with thiophene-2-carbonyl chloride in 2-propanol furnished N-(1-naphthyl)thiophene-2-carboxamide, the treatment of which with an excess of P2S5 in anhydrous pyridine led to the corresponding thioamide. Oxidation of the latter with potassium ferricyanide in an alkaline medium according to the Jacobson method yielded 2-(thien-2-yl)naphtho[1,2-d]thiazole. The latter was introduced into the electrophilic substitution reactions: nitration, bromination, formylation, and acylation. The reactions occur exclusively at the position 5 of the thiophene ring. [ABSTRACT FROM AUTHOR]