Synthesis and structure determination of alicycle-fused thiazolo- and thiazino[2,3-quinazolones and cycloalkylimino-3()-thiazolinylthiazolidines

Starting from various stereoisomeric, alicyclic ethyl 2-aminocarboxylates (1–6, 23, 24) and 2-chloroethyl, 3-chloropropyl or 3-bromopropyl isothiocyanate, ring-closure reactions were performed under mild conditions. Thus, partially saturated thiazolo- and thiazino[2,3-b]quinazolinone derivatives (7–8) and asymmetric 2-[2′-(ethoxycarbonyl-cycloalkyl and -cycloalkenyl)-imino]-3-(2″-thiazolin-2″-yl)-thiazolidine diadducts (19–22) were formed. The structures of the new compounds were proved via their IR, 1H and 13C NMR spectra, use also being made of DR, DNOE, DEPT and 2D-HSC measurements.