Treatment of phthalideisoquinolines such as α- (1) and β-narcotine (2) as well as β- (3) and α-hydrastine (4) with ethyl chloroformate (ECF) at room temperature afforded, via the chloro-carbamates, the corresponding diastereomeric carbinols with high stereoselectivity. Instrumental analyses of each diastereomeric pair indicate that the major isomers derived from α- and β-narcotine as well as from α- and β-hydrastine are enantiomers of each other. The absolute configuration of the major carbinol 6a from α-narcotine (1) was determined by X-ray analysis. The probable difference between the reaction course of α-and β-narcotine is discussed. On the other hand, treatment of α-narcotine with ECF under reflux furnished Z-(8) and E-(9) enol lactones, while only the Z-isomer 12 could be isolated from the degradation of β-hydrastine (3) even at room temperature.
α-纳
可待因(1)和β-纳
可待因(2)以及β-白毛莨灵(3)和α-白毛莨灵(4)与
氯甲酸乙酯(
ECF)在室温下反应,通过
氯甲酸酯中间体,以高立体选择性得到相应的双立体异构羰基醇。每个立体异构体对的仪器分析表明,从α-和β-纳
可待因以及从α-和β-白毛莨灵得到的主要异构体是彼此的立体异构体。α-纳
可待因(1)产生的主要羰基醇6a的绝对构型通过X射线分析确定。讨论了α-和β-纳
可待因反应途径的可能差异。另一方面,α-纳
可待因与
ECF在回流条件下反应生成Z-(8)和E-(9)烯醇内酯,而在室温下仅能从β-白毛莨灵(3)的降解中分离出Z-异构体12。