Formation of 2,4,5-triaryl-4,5-dihydro-1H-imidazoles, (1), from aryl aldehydes. Crystal structures of cis-(1: aryl = pyridin-2-yl), {trans-[(1: aryl = pyridin-2-yl)H]+[OAc]−·3H2O}, {cis-[1: aryl = thien-2-yl]·0.5H2O} and trans-(1: aryl = thien-2-yl)

The preparations of cis-2,4,5-triaryl-4,5-dihydro-1H-imidazoles, (aryl = thien-2-yl or pyridin-2-yl) from aryl aldehydes, ammonium chloride and triethylamine in methanol, and their conversions to the trans-isomers are reported. Crystal structures of cis-(1: aryl = pyridin-2-yl), cis-[1: aryl = thien-2-yl·0.5H2O], trans-(1: aryl = thien-2-yl), and trans-{[(1: aryl = pyridin-2-yl)H]+[OAc]−·3H2O}, have been determined and compared with related structures.