、
(1S,2S)-1-amino-N-cyclopropylsulfonyl-2-ethylcyclopropane-1-carboxamide 在
N,N-二异丙基乙胺 、 N-[(dimethylamino)-3-oxo-1H-1,2,3-triazolo[4,5-b]pyridin-1-yl-methylene]-N-methylmethanaminium hexafluorophosphate 作用下,
以
N,N-二甲基甲酰胺 为溶剂,
以71%的产率得到(1R,23S,26S)-23-tert-butyl-N-[(1S,2S)-1-(cyclopropylsulfonylcarbamoyl)-2-ethylcyclopropyl]-3,21,24-trioxospiro[2,12,20-trioxa-4,22,25-triazatetracyclo[23.2.1.14,7.06,11]nonacosa-6,8,10-triene-18,1'-cyclopropane]-26-carboxamide