Structures of a co-crystal of tautomers of (E)-N-7-chloro-4-(2-methoxycinnamolyhydrazinyl) quinoline and a single tautomer of the 4-methoxy analogue

摘要

A crystal structure determination confirmed that the product from 7-chloroquinilin-4-ylhydrazine and 4-methoxycinnanamic acid had been isolated from MeOCH_2CH_2OH solution as [(E)-N'-7-chloro-4-(4-meth-oxycinnamolyhydrazinyl)quinoline, 1. In contrast, recrys-tallization of the 2-MeO derivative, 2, from the same sol-vent, produced a 1:1 co-crystalline mixture of two tautomers, namely (E) -N'-7-chloro-4-(2-methoxycinnamolyhydrazinyl)quinoline and 7-chloro-4(1 H) quinolinone 3-(2-methoxycinnamoyl)hydrazone, molecules A and B, respectively. Molecules 1 and 2A have "L"-shapes and, in general, have very similar conformations, which differ from that of 2B, mainly arising from the rotation about the (O) C-N(N) bond within the linker unit between the quinolone and methoxyphenyl rings. In both 1 and 2, the 3-dimensional supramolecular arrangements involve strong N-H...N, N-H...O, C-H...O and C-H...π hydrogen bonds, while additionally in 2, there are π...π, C-Cl...π and C-H...Cl intermolecular interactions