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Part-IISynthesis of Pyrimidinesappropriately functionalised, especially at the 2- and 4-positions has attracted greatattention of the medicinal chemists.ZNN1RThe synthesis of condensed pyrimidine systems is a very important process subject toimprovement on various points and parameters. The regularly employed methods forsynthesis of condensed pyrimidines involve mainly, two different approaches asmentioned below.Approach A:Annelation of pyrimidines on an appropriately substituted heterocycle 3 .YZXANNH 2NR2 1Z=OH, NH2, R, H etc;Y= carbonylXApproach B:Annelation of a heterocycle on the appropriately substituted pyrimidine ring 3 .ZZXNBNYN3RN1RApproach A is the most widely used approach for the synthesis of condensed pyrimidines.Under this approach, a variety of o-aminocarbonyl substrates of various heterocycles havebeen cyclocondensed with a host of reagents namely amides, thioamides, imidates,amidines etc., mostly under basic conditions, to afford various condensed pyrimidines,quinazolines, thienopyrimidines, pyrrolopyrimidines, triazolopyrimidines, pteridines,furanopyrimidines, pyridopyrimidines and many more.221