Identification of N-acyl 4-(3-pyridonyl)phenylalanine derivatives and their orally active prodrug esters as dual acting α4β1 and α4β7 receptor antagonists
From a series of N-acyl 4-(3-pyridonyl)phenylalanine derivatives of 4, the trifluoromethyl derivative 28 was identified as a potent, dual acting alpha4 integrin antagonist with activity in primate models of allergic asthma. Investigation of a series of prodrug esters led to the discovery of the morpholinopropyl derivative 48 that demonstrated good intestinal fluid stability, solubility and permeability