Two naturally occurring 1-substituted 4-methoxy-β-carboline (1b, c) weer synthesized from ethyl indole-2-carboxylate (5b) and its 1-benzyl derivative (5a), respectively. The synthesis routes involved elaboration of the ester group of 5a, b, cyclization of the substituent at the 2-position toward the 3-position of the indole nucleus, and functionalization at the 1-position of the β-carboline nucleus by a modified Reissert reaction. The β-carbolites (1b, c) thus prepared should be mother compounds for the synthesis of their congeners.
两种天然存在的1-取代4-甲氧基-β-咔啉(1b,c)分别由
吲哚-2-甲酸乙酯(5b)及其1-苄基衍
生物(5a)合成。合成路线涉及5a、b的酯基的精制、2位取代基向
吲哚核3位的环化,以及通过改进的Reissert在β-咔啉核的1位官能化反应。由此制备的β-carbolites (1b,c)应该是用于合成其同系物的母化合物。