Racemic dihydro-oxocrinine (XVIII) was synthesized from the keto-lactam (X) by a sequence of reactions including the Michael-type cyclization of the αβ-unsaturated keto-lactam (XI) by the use of toluene-p-sulphonic acid. The racemic ketone (XVIII) was resolved into optically active dihydro-oxocrinine (XIX) and dihydro-oxovittatine (XX). The former gave dihydrocrinine (II) or dihydroepicrinine (IV) when reduced by the Meerwein-Ponndorf reaction or by lithium aluminium hydride, respectively. The latter (XX) afforded dihydrovittatine (III) or dihydroepivittatine (V) when similarly reduced.
外消旋二氢-氧分泌宁 (XVIII) 由酮-内酰胺 (X) 通过一系列反应合成,包括使用
甲苯-对-
磺酸对 αβ-不饱和酮-内酰胺 (XI) 进行 Michael 型环化。外消旋酮(XVIII)被拆分成光学活性的二氢-氧代泌
尿素(XIX)和二氢-氧代
维生素A(XX)。前者分别通过 Meerwein-Ponndorf 反应或
氢化铝锂还原时得到二氢外泌宁 (II) 或二氢表泌宁 (IV)。当类似地还原时,后者(XX)提供二氢
维生素E(III)或二氢
维生素E(V)。