| 摘要 |
Cyclic corticoids and their 21C-esters, of formula (I) (where X and X1 = H or F, A = satd. or double bond, R = H or 1-12C alkyl, R1 = H or 1-4C alkyl or alkenyl and R2 = 1-12C alkyl or alkenyl) are made by (a) reaction of 1 mole corticoid with 1.5 moles aldehyde or ketone, in dioxane contg. perchloric acid, under anhydrous conditions; (b) sepn. and purificn. of the cyclic ketal formed; and (c) soln. in pyridine and treatment with the appropriate anhydride to form the required ester.
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