The title compound 2 was prepared from (20R)-pregn-5-ene-3β,20-diyl 3-acetate 20-benzoate (3) via (20R)-3β-acetoxy-20-benzoyloxy-5-oxo-5,6-secopregnan-6-oic acid (5) and (20R)-3β-acetoxy-20-benzoyloxy-7-nor-5β,6α-pregnane-6,5-carbolactone (6). An intermediate 7-norpregn-5-ene derivative - (20R)-7-norpregn-5-ene-3β,20-diyl 3-acetate 20-benzoate (7) - was hydrogenated using diimide in statu nascendi. The inversion of configuration at carbon C-3 was carried out via (20R)-7-nor-5α-pregnane-3β,20-diyl 3-tosylate 20-benzoate (12) and (20R)-7-nor-5α-pregnane-3α,20-diyl 20-benzoate 3-formate (13).
化合物2是从(20R)-孕-5-烯-3β,20-二酰基 3-醋酸酯 20-苯甲酸酯(3)经由(20R)-3β-乙酰氧基-20-苯甲酰氧基-5-氧代-5,6-脱环孕烷-6-酸(5)和(20R)-3β-乙酰氧基-20-苯甲酰氧基-7-去-5β,6α-孕烷-6,5-碳酸内酯(6)制备而来。中间体7-去孕-5-烯衍生物-(20R)-7-去孕-5-烯-3β,20-二酰基 3-醋酸酯 20-苯甲酸酯(7)使用生成状态下的二亚胺氢化。在碳C-3处的构型反转是通过(20R)-7-去-5α-孕烷-3β,20-二酰基 3-对甲苯磺酸酯 20-苯甲酸酯(12)和(20R)-7-去-5α-孕烷-3α,20-二酰基 20-苯甲酸酯 3-甲酸酯(13)实现的。