Benzyl 5-carboxy-4-ethyl-3-methylpyrrole-2-carboxylate

In the title compound, C16H17NO4, the benzyloxycarbonyl group is anti to th e pyrrolic N atom. The molecules are joined into head-to-head dimers by hyd rogen bonds involving the carboxylic acid groups. There is orientational di sorder of these groups over two positions with approximately equal occupanc y. A weaker hydrogen bond between the pyrrolic N atom and the carbonyl O at om of the benzyloxycarbonyl group joins the dimers into chains running para llel to the [110] direction.