Fifty-eight compounds related to phenoxyacetone and phenosyacetamide have been measured as inhibitors of a-chymotrypsin. Substitution of 3-chloro, 2, 3-dichloro, or 3, 4- dichloro groups on phenoxyacetone increased hinding of phenoxyacetone 11-23-fold; bulky groups such as methyl or ethyl were detrimental to binding, brit, flat hydrocarbon substituents such as o-phenyl or benzo were beneficial to binding. Ariilides and E- ...