Improved Access to Imidazole-phosphonic Acids: Synthesis ofD-manno-Tetrahydroimidazopyridine-2-phosphonates
作者:Miroslav Terinek、Andrea Vasella
DOI:10.1002/hlca.200490067
日期:2004.3
by transesterification to the diethyl phosphonate 14 and dealkylation, providing 11 in eight steps from the thionolactam 1 and in an overall yield of 15%. Alternatively, a more highly convergent synthesis based on the HgCl2/Et3N-promoted condensation of the thionolactam 1 with the α-aminophosphonate 24 in THF led to 11 in four steps and in the same overall yield. In the presence of HgCl2/Et3N, the
D-甘露糖基-四氢咪唑并吡啶-2-膦酸酯11是通过高产Pd(PPh 3)4催化甘露糖基-碘咪唑12的二苯基膦酰化反应,然后酯交换反应生成二乙基膦酸酯14和脱烷基,在八个步骤中得到11硫代内酰胺1的化合物,总收率为15%。备选地,基于HgCl 2 / Et 3 N促进的硫代内酰胺1与α-氨基膦酸酯缩合的更高聚合的合成在四步中以相同的总收率得到24的四氢呋喃溶液得到11。在氯化汞的存在下2 / ET 3 N,所述thionolactam 1在80℃用2-甲氧基乙醇反应以提供64的66%:在36混合物葡糖-和甘露-iminoethers 29日/ 30。在22°进行反应优选产生葡萄糖异构体29(86%,84:16)。