Abstract The structure-affinity relationships (SAR) between the N-terminii of a series of α- methyl-tryptophanylphenethylamide derivatives and the cholecystokinin (CCK) B receptor are discussed. A series of compounds with the general formula RX-α-methyl- tryptophanylphenethylamide was prepared, where R is a cycloalkyl, a bicycloalkyl or a tricycloalkyl group and X is a urethane, thiourethane, amide, urea or a sulphinamide ...