5-MEMBERED-RING, 6-MEMBERED-RING AND 7-MEMBERED-RING SUBSTITUTED THIAZOLIDINE-2-THIONE

The X-ray structures of ,6,6a-hexahydro-2H-cyclopenta[d]thiazole-2-thi one, (1), ,3,3a,45,6,7,7a-octahydrobenzo[d]thiazole-2-thione (2), and 4,5,6,7,8,8a-octahydro-2H-cyclohepta[d]thiazole-2- thione, (3), are pr esented. The condensation of a five-, six- or seven-membered ring onto the C4-C5 bond of a thiazolidine-2-thione ring does not affect the fl exibility of the heteroatomic ring, which adopts different conformatio ns in each case. In both compounds (2) and (3), C8H13NS2 (six- and sev en-membered condensed rings, respectively), the observed conformation is half chair, with torsion angles tau (S1-C5-C4-N3) of 36.6(2) and 21 .3(7)degrees, respectively, whereas in compound (1), C6H9NS2 (five-mem bered condensed ring), the thiazolidine-2-thione ring is almost planar [tau = (3)degrees].