Synthesis and Structure of 6,7-Dihydro-2,3-disubstituted 5H-2a-Thia(2a-SIV)-2,3,4a,7a-tetraazacyclopent[cd]indene-1,4(2H,3H)-dithione

Abstract
Symmetrical tetraazapentalene derivatives 5 and 6 were synthesized by a convenient one-pot reaction using lithium thioureide/phenacyl chloride/alkyl (or allyl) isothiocyanate system. Unsymmetrical tetraazapentalene derivatives 8 were prepared by the reaction of various isothiocyanates with thiadiazolopyrimidine derivatives 7 which were derived from symmetrical tetraazapentalene derivatives. The structure of 5c was determined by a single crystal X-ray diffraction.