92910-71-9Relevant academic research and scientific papers
Dihydropyrimidines and Related Structures. I. N2-Substituted 2-Pyrimidinamines and Dihydro-2-pyrimidinamines by Reaction of Phenylbutenones and Monosubstituted Guanidines
Wendelin, Winfried,Schermanz, Karl
, p. 65 - 69 (2007/10/02)
The reactions of monosubstituted guanidines 2 with phenylbutenones 7 and 10 exclusively yield N2-substituted 2-pyrimidinamines 8 and 9.The structure of the reaction products is proved and their differing stability is discussed.Action of methyl- and benzylguanidine respectively (2b,c) on 4-phenyl-3-buten-2-one (7) and of 2c on 1-phenyl-2-buten-1-one (10) under atmospheric oxygen affords aromatic N2-substituted 2-pyrimidinamines 9b and c.The dihydropyrimidines 8b and c, probable intermediates of the reactions, could not be isolated.In contrast, heating of arylguanidines 2d,e with 7 leads to stable dihydropyrimidinamines 8d and e, which can be isolated as bases.Addition of methanol to 8d yields 6-methoxy-2-pyrimidinamine 11d, boiling of 8d in DMF affords 9d.Under nitrogen, guanidine adds to 7 to yield aminopyrimidinol 13a, which is transformed by heating in benzene into pyrimidine 9a.The low stability of 8a-c is attributed to their strong basicity, the greater stability of 8d and e to their lower basicity.The structural formulae of 8d, e and 9b-d and their salts respectively were established partly (8e) by nmr and partly (9b-d) by comparison of the corresponding picrates with authentic samples .
