| abstract |
Corticosteroid-21-hemisuccinate esters and alkali metal salts of formula (I) (where R1 = H or F; R2 = H or Me; R3 = H or alkali metal and dotted line represents an opt. double bond) are prepd. from cpds. of formula (II), and succinic anhydride in the presence of catalytic concns. of tert.-amine base. Opt. the steroid is converted to its salt. At least three molar equivs. of succinic anhydride are used. Reaction temp. is 50-100 deg.C. No solvents are present |