Synthesis of 4-alkyl-3,5-dibromo-, 3-bromo-4,5-dialkyl- and 3,4,5-trialkylpyridines via sequential metalation and metal-halogen exchange of 3,5-dibromopyridine
作者:Yu Gui Gu、Erol K. Bayburt
DOI:10.1016/0040-4039(96)00331-0
日期:1996.4
Lithiation of 3,5-dibromopyridine with LDA and subsequent reaction with electrophiles provided 4-alkyl-3,5-dibromopyridines 2 in high yield. 3-Bromo-4,5-dialkylpyridines 3 were synthesized by metal-halogen exchange of 2 with one equivalent n-BuLi and reaction with a second electrophile. Further metal-halogen exchange of 3 and reaction with a third electrophile provided 3,4,5-trisubstituted pyridines
3,5-二溴吡啶与LDA的锂化以及随后与亲电试剂的反应以高收率提供了4-烷基-3,5-二溴吡啶2。3-溴-4,5- dialkylpyridines 3通过金属-卤素交换合成2用一级当量的n-BuLi并反应与第二电试剂。的另外的金属-卤素交换3和反应与第三电子试剂提供3,4,5-三取代的吡啶4。