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Part-IISynthesis of PyrimidinesTable 28: Condensed 2-Substituted-4-phenylpyrimidinesR 2R 1XN NRR 1 R 2 R X Yield R. Solv. Reference(%)H Cl -CH 3 -HC=CH- 70 B-H 31H Cl -CH 2 Cl -HC=CH- 70 B-H 31H Cl -CH=C(C 6 H 5 )OH -HC=CH- 73 E 55-(-CH 2 -) 4 - -CH 3 S 54 E 31-(-CH 2 -) 4 - -CH 2 CO 2 C 2 H 5 S 57 E 31-(-CH 2 -) 4 - -CH 2 Cl S 51 E 31B = Benzene, C=Chloroform, H = Hexane, E = EthanolThe condensation of o-aminoketoxime 16 with nitriles was found to yield the condensed4-arylpyrimidines via the elimination of hydroxylamine, rather than the expectedcondensed 4-arylpyrimidin-N-oxides 17 (Table 28). 23C 6 H 5ClNC 6 H 5NRCl16NOHNH 2+ RCNXdry HCldry HClClC 6 H 5NO17NRSome novel 2-substituted-4-phenylpyrido[3,2-d]pyrimidines have also been obtainedthrough the dry HCl gas catalysed condensation of the corresponding pyridothiophene o-aminoketone 11c with nitriles like acetonitrile and chloroacetonitrile (Table 29). 56243