1-Methylindole-3-carboxaldehyde oxime derivatives

1-Methylindole-3-carboxaldehyde oxime, C10H10N2O, (I), and (E)-5-methoxy-1- methylindole-3-carboxaldehyde oxime, C11H12N2O2, (II), were examined struct urally to ascertain the geometry of the hydroxyimino function relative to t he indole core. Oxime (I) exhibits cis geometry and there are two molecules in the asymmetric unit. In contrast, oxime (II) exhibits trans geometry an d has four molecules in the asymmetric unit, with the geometry of the 5-met hoxy group in one molecule differing from that in the other three. Both cry stal structures are maintained by hydrogen bonding with no pi -stacking of the indole moiety present.