3β-acetoxy-16α-nitromethyl-5-pregnan-20-one 、 (3aR,4S,5R,6aR)-5-(2,2-dimethyl-[1,3]dioxolan-4R-yl)-2,2-dimethyl-6-prop-2-ynyloxy-tetrahydrofuro[2,3-d][1,3]dioxole 在
异氰酸苯酯 、
三乙胺 作用下,
以
苯 为溶剂,
以65%的产率得到[(3S,8S,9S,10R,13S,14S,16R,17S)-16-[5-[[(3aR,5R,6S,6aR)-5-[(4R)-2,2-dimethyl-1,3-dioxolan-4-yl]-2,2-dimethyl-3a,5,6,6a-tetrahydrofuro[2,3-d][1,3]dioxol-6-yl]oxymethyl]-1,2-oxazol-3-yl]-17-acetyl-10,13-dimethyl-2,3,4,7,8,9,11,12,14,15,16,17-dodecahydro-1H-cyclopenta[a]phenanthren-3-yl] acetate