WJ X a series, n= 0; b series, n= 1 1, X= 3, 4-(OCH,), 2, X= 4-NH2 3, X= 4-NHCOCH= CH2 4, X= 4-NHCOCHzCl 5, X= 4-NHCHzCH, Cl 6, X= 4-NHCOCH= CHCOOCH3 (cis) 7, X= 4- NHCOCH= CHCOOCH3 (trans) inhibitor of phosphodiesterases, it rarely shows appreciable tissue selectivity in its a~ tions.~?~ Baker has suggested that a potent inhibitor of an enzyme might be made more specific by addition of a moiety that could form a covalent bond with ...