(1S)-2-acetylsulfanylmethoxy-5-bromo-1-[(1S)-1-tert-butoxycarbonylamino-2-hydroxy-ethyl]-6-methoxy-1,2,3,4-tetrahydro-β-carboline-9-carboxylic acid 1-chloro-ethyl ester 、
甲基磺酰氯 在
N,N-二异丙基乙胺 作用下,
以
二氯甲烷 为溶剂,
以92%的产率得到(1S)-2-acetylsulfanylmethoxy-5-bromo-1-[(4S)-1-tert-butoxycarbonylamino-2-methanesulfonyloxy-ethyl]-6-methoxy-1,2,3,4-tetrahydro-β-carboline-9-carboxylic acid 1-chloro-ethyl ester