Borohydride reduction of titled ketones 1a-1g gave diastereoisomeric mixtures of (Z)-1,3-diphenyl-3-(2-phenylimidazo[1,2-a]pyridin-3-yl)prop-2-en-1-ols 2a-2g and 3a-3g in which the former ones prevailed. Only individual racemic products were obtained after borohydride reduction of (E)-1,3-diphenyl-3-(2-phenylimidazo[1,2-a]pyridin-3-yl)-prop-2-en-1-one 4 to corresponding 1-hydroxy derivative 5 and by conversion of (Z)-1-oxo derivative 1a to 1,3-diphenyl-3-(2-phenylimidazo[1,2-a]pyridin-3-yl)propan-1-one (6) with sodium hydrogenselenide. Diastereoselectivity of the borohydride reduction is discussed using the PM3 calculations of the molecules 1a, 2a, 2b, 3a, 3b, 4, 5, and 6.
对于标题酮化合物1a-1g的
硼氢化还原反应,得到了(
Z)-1,3
-二苯基-3-(
2-苯基咪唑[1,2-
a]
吡啶-3-基)
丙-2-烯-1-醇化合物2a-2g和3a-3g的对映异构体混合物,前者占优势。对于(
E)-1,3
-二苯基-3-(
2-苯基咪唑[1,2-
a]
吡啶-3-基)-丙-2-烯-1-酮化合物4的
硼氢化还原反应,仅获得了对应的1-羟基衍
生物5的单一外消旋产物,通过将(
Z)-1-酮衍
生物1a转化为1,3
-二苯基-3-(
2-苯基咪唑[1,2-
a]
吡啶-3-基)
丙酮-1衍
生物6,使用氢
硒酸钠。通过对分子1a、2a、2b、3a、3b、4、5和6的PM3计算,讨论了
硼氢化还原的对映选择性。