SYNTHESIS AND REGIOSELECTIVE [4-ARYLAMINO-1,3-DIAZA-1,3-BUTADIENES WITH KETENES AND ACCOMPANYING REARRANGEMENTS(2] CYCLOADDITION NUCLEOPHILIC REACTIONS OF N)

N-Arylamino-1,3-diaza-1,3-butadienes 4 are shown to undergo regioselec tive reactions with phenyl- and chlorokete resulting in high yields of 3-aryl-2-methylthio-6-phenyl-4(3H)-pyrimidinones 7. Similar reactions with bromo- and iodoketenes, resulted, via aziridinirum intermediates 12, in good yields of ylamino)-2-methylthio-6-phenyl-4(3H)-pyrimidino nes 13. The mechanistic aspects of cycloadditions and semi-empirical A M1 calculations for these diazabutadienes are also reported.