Patent / 1988
Novel process for the preparation of steroidal esters
Title compds. I [X = H, Cl, F; R1 = H, F, Cl, Me; R2 = halo, oxo, hydroxy; R3 = H, .alpha.- or .beta.-Me; R2X = O; R4 = RCO (R = alkyl, aralkyl, Ph); R5 = OH, R6 (R6 = H, R7CO2 where R7 = alkyl, aralkyl, Ph) a dashed line may be a double bond (II)], useful as drugs, are prepd. from I (R2 = trihaloacetoxy, H, oxo; R2X = O R4 = H) (III). Treatment of a mixt. of dexamethasone 11-trifuloacetate 21-acetate and MeSO3H with a mixt. of CF3CO2H and (Me2CHCO)2O at 60.degree. for 3 h gave dexamethasone 11-trifluoroacetate 17-isobutyrate 21-acetate, which in MeOH was treated with Et3N at 25.degree. for 1 h to afford dexamethasone 17-isobutyrate 21-acetate, whose vasoconstriction activity was 1280, vs. 100 for fluocinolone acetamide. An ointment was formulated contg. dexamethasone 17,21-dipropionate 0.1 (as dexamethasone), liq. paraffin 8.1, and solid vaseline 91.8%.