Benzoylisothiocyanate, reaction with

DCC treatment of the thiourea (57 X = CH, N), prepared from the amine (56) by reaction with benzoylisothiocyanate followed by base hydrolysis, affords the tetracyclic derivatives (58) which are claimed to possess considerable antitumour activity in vitro <94H(38)1213>. In an alternative synthesis, (58) may be prepared by methylation of the thiourea group in (57) with methyl iodide followed by treatment with K2CO3 in DMF. The imino-tautomer structure is base upon NMR and infrared spectroscopic evidence. 

Reaction of 281 with benzoylisothiocyanate afforded pyrimido[4,5-frJ-benzolfrjpyran 493, which was assumed to be formed via the respective open-chain thiourea derivative (89JPR971) (Scheme 105). 

The 8-methylene carbon atom in 5,6,7,8-tetrahydroquinazoline was activated by the pyrimidine ring, and reacted with formamide and phosphoryl chloride (a Vilsmeier reagent) to form 8-formamidomethylene-5,6,7,8-tetra-hydroquinazoline.197 The latter was also obtained as a by-product in the synthesis of 5,6,7,8-tetrahydroquinazoline from cyclohexanone and trisform-amidomethane.1982-Phenyl-5,6,7,8-tetrahydroquinazoline-4(3//)-thione was synthesized from 1-morpholinocyclohex-l-ene and benzoylisothiocyanate. The thione group underwent the usual metathesis reactions.199 2-Methyl-5,6,7,8-tetrahydroquinazoline-4(3//)-thione was oxidized with potassium permanganate to 2-methyl-4-sulfo-5,6,7,8-tetrahydroquinazoline, which provided 2-methyl-5,6,7,8-tetrahydroquinazolin-4(3//)-one on hydrolysis.145... 

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