Lipophilicity and serotonin agonist activity in a series of 4-substituted mescaline analogues.

Replacement of the 4-methoxy of mescaline with higher alkyl homologues or with bromine led to increased activity at serotonin receptors in a sheep umbilical artery preparation. This activity appears correlated with lipophilicity, as measured by 1-octanol-water partition coefficients, but drops off when the 4-substituent is about five atoms in length. It is suggested that 3,4,5-trisubhe 2,4,5-substitution pattern.