Carbamates I: structural and conformational study of eight methoxyphenyl-N-pyridinylcarbamates

Abstract

Crystal and molecular structures of phenyl carbamates are relatively unexplored. Only 33 basic phenylcarbamates are present on the Cambridge Structure Database with no phenyl-N-pyridinylcarbamates (Scheme 1a). Our field is structural systematics and isomer grids by bridging solid state crystallography and in silico molecular modeling with conformational analysis as a central tool. A 3×3 isomer grid of nine Methoxyphenyl-N-pyridinylcarbamates (C13H12N2O3) as CxxOMe (x = para-/meta-/ortho-) was synthesized and studied to determine their crystal structures and correlate structural relationships from both ab initio calculations and the solid-state using conformational analysis. Eight of nine crystal structures were determined using single crystal X-ray diffraction. All isomers form N-H···N hydrogen bonds as the primary interaction, with one isomer (CmmOMe, Fig. 1) forming a relatively unusual disordered hydrogen bonded trimer via N-H···N interactions, while the CoxOMe isomers (Figs. 2, 3 and 5) form N-H···N hydrogen bonded dimers.