A crystallographic and theoretical study of the conformation of DOET and its significance for the hallucinogenic amphetamines

The crystal structure of DOET, a psychedelic compound, was determined using X-ray crystallography. No hydrogen bonding was found in the solid state. The side chain of the molecule adopts a staggered position relative to the benzene ring, with the α-methyl group fully extended away from the ring and the amino group bent back toward it. Theoretical calculations revealed six possible side-chain positions with very small energy differences, one matching the crystal form. These findings are compared to the structures of related hallucinogens, mescaline and TMA.

Study at a glance

Abstract

Abstract The crystal and molecular structure of 2,5-dimethoxy-4-ethyl-α-methyl-phenylethylamine (DOET) has been determined by X-ray crystallography and the conformation of the side chain has been examined theoretically by the use of a potential energy calculation. There is no indication in the solid state of any intra or inter-molecular hydrogen bonding. The isopropylamine side chain is staggered to the plane of the benzene ring. The α-methyl group is fully extended (antiplanar) whereas the amino group is orientated back towards the ring (synclinal). The potential energy calculations show the existence of 6 minima, one of which corresponds to the crystal position. The calculations also show that the energy differences between the various minima of the side chain are very small. The relationship of these data to the conformations of the hallucinogens, mescaline and 2,4,5,-trimethoxyamphetamine is discussed.