The conformational analyses of 2-amino-N-[2-(dimethylphenoxy)ethyl]propan-1-ol derivatives in different environments

Abstract

Four crystal structures of 2-amino-N-(dimethylphenoxyethyl)propan-1-ol derivatives, characterized by X-ray diffraction analysis, are reported. The free base (R,S)-2-amino-N-[2-(2,3-dimethylphenoxy)ethyl]propan-1-ol, C13H21NO2, 1, crystallizes in the space group P21/n, with two independent molecules in the asymmetric unit. The hydrochloride, (S)-N-[2-(2,6-dimethylphenoxy)ethyl]-1-hydroxypropan-2-aminium chloride, C13H22NO2 +·Cl−, 2c, crystallizes in the space group P21, with one cation and one chloride anion in the asymmetric unit. The asymmetric unit of two salts of 2-picolinic acid, namely, (R,S)-N-[2-(2,3-dimethylphenoxy)ethyl]-1-hydroxypropan-2-aminium pyridine-2-carboxylate, C13H22NO2 +·C6H4NO2 −, 1p, and (R)-N-[2-(2,6-dimethylphenoxy)ethyl]-1-hydroxypropan-2-aminium pyridine-2-carboxylate, C13H22NO2 +·C6H4NO2 −, 2p, consists of one cation and one 2-picolinate anion. Salt 1p crystallizes in the triclinic centrosymmetric space group P\overline 1, while salt 2p crystallizes in the space group P41212. The conformations of the amine fragments are contrasted and that of 2p is found to have an unusual antiperiplanar arrangement about the ether group. The crystal packing of 1 and 2c is dominated by hydrogen-bonded chains, while the structures of the 2-picolinate salts have hydrogen-bonded rings as the major features. In both salts with 2-picolinic acid, the specific R 1 2(5) hydrogen-bonding motif is observed. Structural studies have been enriched by the generation of fingerprint plots derived from Hirshfeld surfaces.