1,2,4-Thiadiazol-5(2H)-imines

Thiadiazole derivativesThiadiazole derivatives R 0300 Cycloaddition of N-(2,2,2-Trichloroethylidene)-Substituted Carboxamides and Carbamates to 1,2,4-Thiadiazol-5(2H)-imines. -Thiadiazole imines (V) react with the title carboxamides or carbamates derived from compounds (VI) to form [3+2]cycloadducts (VII) in good yield. Alkylation of these cycloadducts occurs selectively at the oxygen atom and is accompanied by a "switch-over" of the S-N bond restoring the original 1,2,4-thiadiazole ring. -(ZYABREV*, V. S.; RENSKY, M. A.; RUSANOV, E. B.; DRACH, B. S.; Heteroat. Chem. 14 (2003) 5, 474-480; Inst. Bioorg. Chem. Petrochem., Acad. Sci. Ukr., Kiev 253660, Ukraine; Eng.) -F. Santoso 45-113

No abstract

The paper is concerned with chemistry of thiazolo [4,5-d]pyrimidine derivatives bearing a 1,3-diazapropenylidene fragment at position 2 and an oxygen or a mobile chlorine atom at position 7. These compounds are obtained in three steps: (i) cycloaddition of malononitrile to available 1,2,4-thiadiazol-5(2H)-imines to form N-(4-amino-5-cyanothiazol-2(3H)-ylidene)amidines; (ii) their acylation or condensation with DMF dimethyl acetal followed by; (iii) pyrimidine ring closure.