(4RS)-4-(cyclohexylmethyl)-2-phenyl-4,5,6,7-tetrahydropyrazolo[1,5-a]pyrazine 、
N,N'-双(叔丁氧羰基)-L-胱氨酸 在
N,N-二异丙基乙胺 、 Methanaminium,N-[(dimethylamino)(3H-1,2,3-triazolo[4,5-b]pyridin-3-yloxy)methylene]-N-methyl-, hexafluorophosphate(1-) 作用下,
以
四氢呋喃 、
乙腈 为溶剂,
以73%的产率得到tert-butyl {(1R)-1-[({(2R)-2-[(tert-butoxycarbonyl)amino]-3-[(4RS)-4-(cyclohexylmethyl)-2-phenyl-6,7-dihydropyrazolo[1,5-a]pyrazin-5(4H)-yl]-3-oxopropyl}dithio)methyl]-2-[(4RS)-4-(cyclohexylmethyl)-2-phenyl-6,7-dihydropyrazolo[1,5-a]pyrazin-5(4H)-yl]-2-oxoethyl}carbamate