Synthesis of 6-substituted pyrido[3,4-d]pyrimidin-4(3H)-ones via directed lithiation of 2-substituted 5-aminopyridine derivatives
作者:Gordon W. Rewcastle、William A. Denny、R. Thomas Winters、Norman L. Colbry、H. D. Hollis Showalter
DOI:10.1039/p19960002221
日期:——
pivaloyl derivatives of 2-substituted 5-aminopyridines with BuLi–TMEDA in diethyl ether at –10 °C gave 4-lithio derivatives which were quenched with CO2 to give the analogous C-4 carboxylic acids. Hydrolysis of the protecting groups with either TFA or aqueous KOH gave 2-substituted 5-aminopyridine-4-carboxylic acids which were converted to 6-substituted pyrido[3,4-d]pyrimidin-4(3H)-ones by reaction with formamide
在–10°C下在乙醚中用BuLi–TMEDA对2-取代的5-氨基吡啶的Boc或新戊酰基衍生物进行直接锂化,得到4-硫代衍生物,将其用CO 2淬灭,得到类似的C-4羧酸。用TFA或KOH水溶液水解保护基团,得到2-取代的5-氨基吡啶-4-羧酸,其通过与CH 2反应转化为6-取代的吡啶并[3,4- d ]嘧啶-4(3 H)-。甲酰胺,或更理想的是乙酸甲am。Boc保护的氨基吡啶提供了最佳的整体效果,这些衍生物的合成最好通过在不添加碱的情况下使氨基吡啶与二碳酸二叔丁酯直接反应来实现。
First functionalization by metallation of the pyridine moiety of pyridopyrimidin-4(3H)-ones. Diazines. Part 36
o-aminopyridine carboxylic acids, a general synthetic route leading to various pyridopyrimidin-4(3H)-ones is described. The first metallation and functionalization of the pyridine moiety has been studied and a regioselective metallation at the peri-position C5 of the pyridine ring has been highlighted.