Determination of Ring Conformation in 1-Benzyl-1,2,3,4-tetrahydroisoquinolines and a New Synthesis of the Chiral Compounds.
作者:Tatsumi SHINOHARA、Akira TAKEDA、Jun TODA、Takehiro SANO
DOI:10.1248/cpb.46.430
日期:——
The conformation of the piperideine ring in 1-benzyl-1, 2, 3, 4-tetrahydroisoquinolines was determined as 2H3 form with a pseudoaxial position of the 1-benzyl group by circular dichroism (CD) spectral comparison with 1-methyl-1, 2, 3, 4-tetrahydroisoquinolines. The chiral center at C-1 of 1, 2, 3, 4-tetrahydroisoquinoline (TIQ) was constructed in an unambiguous manner by applying a new method of TIQ synthesis utilizing the Pummerer reaction as a key step. Enantiomerically pure (R)- and (S)-1-methyl- and 1-benzyltetrahydroisoquinolines (1) were prepared starting from readily available chiral amines (2) in good overall yields.
通过对圆二色谱(CD)的比较,确定了1-苄基-1,2,3,4-四氢异喹啉中的哌啶环构象为2H3形式,1-苄基处于假轴向位置。通过应用以Pummerer反应为关键步骤的新型四氢异喹啉(TIQ)合成方法,在C-1位上构建了TIQ的手性中心,方法明确无误。从易获得的 chiral amine(2)出发,以良好的整体产率制备了光学纯的(R)-和(S)-1-甲基和1-苄基四氢异喹啉(1)。