Novel process for the conversion of a sapogenin to

专利名称：Novel process for the conversion of a sapogenin to a 16-dehydro steroid and
intermediates produced thereby
发明人：TANABE MASATO
申请号：US55268166
申请日：19660525
公开号：US3294785A
公开日：
19661227
专利内容由知识产权出版社提供
摘要：The invention comprises (1) steroids of the formulae (wherein Z is the A, B and C rings of a steroidal sapogenin having a 3-hydroxy or -C1- 12 alkanoyloxy group and at the S-position an a - or b -hydrogen atom or a D 5 double bond; Y is a halogen atom; and R3 is hydrogen, alkyl, aryl or aralkyl); and (2) a process for the preparation of a 16-dehydro-20-keto-pregnane compound wherein a sapogenin is reacted with an amidinium salt containing the grouping and obtained by reacting an amide RR1NCOR3 (wherein R and R1 are alkyl, aryl or aralkyl and R3 is hydrogen, alkyl, aryl or aralkyl) with a resistive halide, e.g. phosgene, thionyl chloride, phosphorus oxychloride, chlorosulphonic acid and p-toluenesulphonyl chloride, to form a mixture of compounds of the above general formulae wherein Y is the anion of the amidinium salt and Z is the residue of any sapogenin (in which free hydroxy groups are preferably protected, e.g. acylated), and this mixture is reacted with a base and the product oxidized. Alternatively, compounds II and III may be separated, e.g. by fractional crystallization or chromatography, compounds II oxidized to compounds IV below and these basified to give th required pregnane compounds, or compounds III basified to give compounds V below and these oxidized to
give the required pregnane compounds If the starting material is a sapogenin 3-alkanoate, after reaction with a base the reaction mixture is neutralized and the product re-esterified before oxidation. The products of base treatment and oxidation are suitably treated with basic alumina before isolation of the required pregnane. Examples are given.
申请人：SCHERING CORPORATION
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