Synthesis of pure stereoisomers of benzo[b]thienyl dehydrophenylalanines by Suzuki cross-coupling. Preliminary studies of antimicrobial activity
作者:Ana S. Abreu、Paula M.T. Ferreira、Luís S. Monteiro、Maria-João R.P. Queiroz、Isabel C.F.R. Ferreira、Ricardo C. Calhelha、Letícia M. Estevinho
DOI:10.1016/j.tet.2004.09.107
日期:2004.12
benzo[b]thienyldehydrophenylalanines were synthesized from pure stereoisomers of the methyl ester of N-(tert-butoxycarbonyl)-β-bromodehydrophenylalanine as an extension of our previously reported method for the synthesis of dehydrotryptophan analogues to dehydrophenylalanine derivatives. The latter were obtained in high yields by N-deprotection and bromination of N,N-bis-(tert-butoxycarbonyl)-(Z)-dehydrophenylalanine
由N-(叔丁氧羰基)-β-溴代氢苯丙氨酸甲酯的纯立体异构体合成了几种苯并[ b ]噻吩基脱氢苯丙氨酸,作为我们先前报道的将脱氢色氨酸类似物合成为脱氢苯丙氨酸衍生物的方法的扩展。后者通过TFA和NBS通过N-脱保护和溴化N,N-双-(叔丁氧基羰基)-(Z)-脱氢苯丙氨酸以高收率获得。这是分两个步骤进行的,也可能是一个罐的操作,从而产生不同的E / Z比率。这些化合物在铃木交叉偶联条件下[Pd(PPh 3)4,Na 2 CO 3,DME / H 2 O]与几种硼苯并[ b ]噻吩基酸以良好或高收率偶联,保持了起始原料的立体化学。当硼酸在苯并[ b ]噻吩的7位上并且与溴化脱氢苯丙氨酸的E异构体一起时,可获得最佳收率。在某些情况下,可以通过将Pd源更改为PdCl 2(PPh 3)2来提高较低的产量。制备了模型二肽偶联苯并[ b]噻吩基脱氢苯基丙氨酸与丙氨酸的甲酯。对获得的β,β-二芳基脱氢丙氨酸