HETEROCYCLIC-SYSTEMS CONTAINING BRIDGEHEAD NITROGEN ATOM .74. REACTION OF 3,4,5,6-TETRAHYDROBENZO[H]QUINAZOLINE-2(1H)-THIONE WITH ALPHA-HALOACIDS AND DIBROMOETHANE

5,6-tetrahydrobenzo[h]quinazoline-2(1H-thione(II), obtained by the con densation of 2-benzylidene-tetraline-1-one(I) with thiourea, on reacti on with chloroacetic acid, alpha-bromopropionic acid and 1,2-dibromoet hane furnishes compounds III, IV and V and not their other possible is omers, 5H-5-phenyl-6, 7-dihydrothiazolo[3, 2-a]benzo[h]quinazoline-1(2 H)-one-VII, 5H-2-methyl-5-phenyl-6, thiazolo[3,2-a]benzo[h]quinazoline -1(2H)-one(VIII) and 5H-5-phenyl-1, 2, 6, -tetrahydrothiazolo[3,2-a]be nzo[h]quinazoline(IX), respectively. Arylidenethiazolidinones VI have been obtained by two routes. Compounds III-V represent a novel and hit herto unknown heterocyclic system. The structural assignments of III, IV and V are based on H-1 NMR spectral data.