The Mannich reaction of 7-aryl-5,6-dihydropyrido[2,3-d]pyrimidines 3, easily accessible by condensation of 6-amino-1,3-dimethyluracil (1) with Mannich bases 2a - c, gives rise to a mixture of 7-aryl-6-(N,N-dimethylaminomethyl)pyrido[2,3-d]pyrimidines 6 and 7 as well as 1,2-bis- (7-arylpyrido[2,3-d]pyrimidin-6-yl)ethane 13 the ratio of which depends on the reaction conditions and the amine used. 6-Alkylamino-1,3-dimethyluracils 15 - 18 were converted to the corresponding 5-(3-oxo-3-phenylpropyl)uracils 19 - 22 by condensation with the Mannich base 2a. Ring closure of 19 - 22 was performed by Vilsmeier formylation to afford the 8-alkyl- and 7,8-diaryl-5,8- dihydropyrido[2,3-d]pyrimidine-6-carbaldehydes 9 - 12 via the corresponding iminium salts 27 - 30
7-芳基-5,6-
二氢吡啶并[2,3-d]
嘧啶的Mannich反应3,通过6-
氨基-1,3-二甲基尿
嘧啶(1)与Mannich碱2a-c缩合而得,形成了一种混合物,其中包括7-芳基-6-(N,N-
二甲胺基甲基)
吡啶并[2,3-d]
嘧啶6和7,以及1,2-双-(7-芳基
吡啶并[2,3-d]
嘧啶-6-基)
乙烷13,其比例取决于反应条件和所使用的胺。6-烷基
氨基-1,3-二甲基尿
嘧啶15-18通过与Mannich碱2a缩合转化为相应的5-(3-氧代-3-苯基丙基)尿
嘧啶19-22。将19-22进行Vilsmeier甲酰化环合,得到8-烷基和7,8-二芳基-5,8-
二氢吡啶并[2,3-d]
嘧啶-6-
甲醛9-12,通过相应的
亚胺盐27-30。