Pyrimidinones and Quinazolinones

A -Benzyl groups on pyrimidinones and quinazolinones are removable by hydrogenolysis, although it is now more common to use a PMB substituent that can be removed with either TFA or CAN. Other N-protecting groups to be commonly used include benzyloxymethyl (BOM), removable by hydrogenation, ferZ-butoxycarbonyl (BOC), removable by anhydrous acid, and pivaloyloxymethyl (POM), which is removable by methanolic ammonia at room temperature. Alkenyl pyrimidinones have been employed in 1,3-dipolar cycloaddition reactions to prepare heterocyclic nucleotides. 

Bonacorso HG, Costa MB, Lopes IS, Oliveira MR, Drekener RL, Martins MAP, Zanatta N, Flores AFC (2005) Synthesis of tetrahydro-2(lH)quinazolinones, cyclopenta[d]-2(lH) pyrimidinones and their thioxoanalogs from 2-trifluoroacetyl-l-methoxycycloalkenes. Synth Commun 35 3055-3064... 

Quinazolin-2(and 4)-one were first shown to exist as 0x0 tautomers by IR and UV spectroscopic comparisons akin to those above (52JA4834, 51JCS3318) like its pyrimidinone analogue, the quinazolinone (41) prefers that configuration to the pczra-quinonoid tautomer (57JCS4874), a conclusion upheld by the NMR study of simple analogues (69T783). 

Armarego studied the reduction of quinazolinones 244 and cyclopenta-pyrimidinones 246. The reduction with platinum(IV) oxide as catalyst was found to be highly stereospecific, resulting only in the cw-fused derivatives 245 and 247, respectively [74JCS(P1)2313 76JCS(P1)1415]. 

A 2-acyiaminobenzonitrile is converted into a quinazolinone under basic and oxidizing conditions [3771], while the amidroxamine (treatment with hot ethanolic alkali [3429]. 

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