Synthesis of new heterocyclic ring systems via nucleophilic subsititution of pyrimido [4,5-d] pyridazines
作者:K.J. Szabó、J. Császár、A. Toró
DOI:10.1016/s0040-4020(01)89084-0
日期:——
2-phenyl- and 2-aminopyrimido [4,5-d] pyridazines by better leaving groups (C1, OSiMe3 and SMe, OSiMe3 respectively), and the 5,8-disubstituted compounds were substituted by aminoalkanols. The 5- and 8-mono(ω-hydroxyalkylamino) derivatives obtained in regioselective reactions were cyclized into imidazo [1,2-b] pyrimido [5,4-d] pyridazine, imidazo [1,2-b] pyrimido [4,5-d] pyridazine, dipyrimido[1,2-b:5′
C 5和C 8位的羟基被更好的离去基团(分别为C1,OSiMe 3和SMe,OSiMe 3)取代为2-苯基-和2-氨基嘧啶[4,5-d]哒嗪,而5,8 -二取代的化合物被氨基链烷醇取代。将在区域选择性反应中获得的5和8-单(ω-羟烷基氨基)衍生物环化成咪唑并[1,2-b]嘧啶[5,4-d]哒嗪,咪唑并[1,2-b]嘧啶[4, 5-d]哒嗪,二嘧啶基[1,2-b:5',4'-d]哒嗪和二嘧啶基[1,2-b:4',5'-d]哒嗪衍生物含有新的杂环系统。动力学测量和MNDO计算表明,哒嗪环上的C 8位比C 5更具反应性和氨解如下通过通常的两步骤Ñ氩机制。