作者:Chuansheng Niu、Jun Li、Terrence W. Doyle、Shu-Hui Chen
DOI:10.1016/s0040-4020(98)00328-7
日期:1998.6
methylboronic acid with 2-chloro-3-nitropyridine produced 2-methyl-3-nitropyridine 4 in one step in high yield. Oxidation of 4 with selenium dioxide gave aldehyde 5. Alternatively, condensation of 4 with DMFDMA followed by oxidation gave 5 in a two step higher yielding conversion. Subsequent direct coupling of 5 with thiosemicarbazide followed by reduction of the nitro group using stannous chloride or sodium
钯催化的甲基硼酸与2-氯-3-硝基吡啶的交叉偶联一步一步即可制得2-甲基-3-硝基吡啶4。用二氧化硒氧化4得到醛5。或者,将4与DMFDMA缩合,然后氧化,以两步较高的产率得到5。随后将5与硫代氨基脲直接偶联,然后使用氯化亚锡或硫化钠还原硝基,得到3-AP(3)。用亚硫酸氢钠还原得到3-HAP(8)。最后,设计了避免硝基功能降低的途径。因此,在Heck反应条件下,苯乙烯与2-氯-3-氨基吡啶9的直接偶合得到16,该16转化为17,氧化为醛18并转化为3-AP(3),并具有对t- Boc官能团的原位解封。