3.4.5.6- Tetrahydrobenzo quinazoline

However, another representative of benzo-fused tetrahydropyrimidines, 3,4,5,6-tetrahydrobenzo[/i]quinazoline 61, was reported to exist exclusively as the tautomer shown, without any indication of the annular tautomeric equilibrium (91M209). 

Kaur and co-workers [127] investigated the acid catalyzed condensation of tetralone, thiourea and a substituted benzaldehyde in acetonitrile under micro-wave irradiation to obtain 4-phenyl-3,4,5,6-tetrahydrobenzo[/i]quinazoline-2(l//)-thiones 91. A domestic microwave oven was used and the targeted compounds were obtained in moderate yields (Scheme 68). 

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