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hydrin formation, closure t o the 9,110-oxide and opening with hydrogen fluoride gave 6 c t , 9 ~ ~ difluoro- 16a-methylprednisolone 2 1-acetate (I11), m.p. 2.57-259' (dec.), A;&', 238 mp ( E 16,500). Satisfactory analyses were obtained for the compounds. 'The biological effects of these new hydrocortisone analogs will be reported in detail elsewhere by members of the Upjohn Company Endocrinology Department. As examples of the type of potentiation of activity observed, lie-fluoro-16amethylhydrocortisone acetate (I), Ga-fluoro-llicu~iiethplprednisolone acetate (11), and Cia,Sa-difluoro-1 Ga-methylprednisolone acetate (111) were, 111 L \' V respectively, approximately 40, 160 and 700 times This "inversion" of the two carbon bridge reas active as hydrocortisone in the liver glycogen quires t h a t the B/C junction be cis in one member deposition assay." of the gibberic-allogibberic acid pair while t r a m (11) Irein7 i t i A w I'rw. Soc. E'xp. B i d . M e t i . , 89, 371 (1933). \Ve are indebted in the other. In view of this, it is illuminating !
