antiinflammatory activity is exhibited by pregnenes having the structural formula ## str1 ## wherein r 1 is hydrogen , hydroxy , halogen , or acyloxy ; r 2 and r 3 are each hydrogen , r 2 and r 3 are each methyl , r 2 and r 3 are each alkylthio , r 2 is hydrogen and r 3 is alkyl , r 2 is hydroxyl and r 3 is alkyl , or r 2 and r 3 taken together are -- 2 --, methylene , or oxo ; and r 4 is hydrogen , fluorine , chlorine or bromine .