| 摘要 |
Novel cyclization substrates are disclosed of the formula <IMAGE> (III) wherein: (a) R1 is H or alkyl of one to four carbon atoms; (b) R2 is H or alkyl of one to four carbon atoms, with the proviso that R1 is H when R2 is alkyl, and with the proviso that R2 is H when R1 is alkyl; (c) R3 is a leaving group selected from the group consisting of hydroxy, alkoxy of one to four carbons, alkoxyalkoxy of two to four carbons, acyloxy of one to about seven carbons, and trialkylsilyloxy of less than fifteen carbons; (d) R4 is hydrocarbyl of one to four carbon atoms, a hydrocarbyl of one to two carbon atoms substituted by halogen or alkoxy of one to two carbons, or alkoxy of one to four carbon atoms; and (e) R5 and R5' each are H, OH, alkyl, trialkylsilyloxy, or an esterified or etherified hydroxy-group of about one to ten carbon atoms. A method is disclosed for the cyclization of the compounds of formula III leading to novel and biologically active compounds of the following formulae: <IMAGE> +TR <IMAGE> having R1 through R5' as defined above, with R6 being alkyl of from one to about four carbon atoms, among which are intermediates for preparing well-known biologically active 7 alpha -substituted steroids, such as 7 alpha -methyl-oestrone; 7 alpha -methoxy-oestradiol and the like.
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