Patent / 1976
Sulfate and phosphate 21-esters of corticosteroids
Betametasone (I) 21-phosphate (II) was prepd. in 96.7% yield by refluxing III (R = I) in 40 ml acetone with 1.2 g H3PO4 and 5.8 ml Et3N for 3.5 hr. Salts of I 21-sulfate and II with PhCH2NHCH2CH2NHCH2Ph also were prepd.