Crystal structures of methyl 3-phenyl-4,5-dihydro-1H,3H-benzo[4,5]imidazo[2,1-c][1,4]oxazepine-4-carboxylate and methyl 1-methyl-3-phenyl-4,5-dihydro-1H,3H-benzo[4,5]imidazo[2,1-c][1,4]oxazepine-4-carboxylate

Abstract

The title compounds, C19H18N2O3, (I), and C20H20N2O3, (II), differ only by a methyl substituent on the seven-membered oxazepine ring in (II). In both compounds, these rings have a twist-chair conformation. The phenyl ring makes a dihedral angle of 73.42 (10)° with the benzimidazole ring system mean plane (r.m.s. deviation = 0.015 Å) in (I) and 83.07 (7)° in (II) (r.m.s. deviation = 0.026 Å). The methyl carboxylate groups are planar to within 0.031 (2) in (I) and 0.003 (2) Å in (II). They are inclined to the phenyl and benzimidazole ring system by 33.78 (16) and 87.56 (14)°, respectively, in (I) and by 53.04 (12) and 60.22 (11)°, respectively, in (II). In the crystal of (I), molecules stack in a herringbone fashion and are linked by C—H...O hydrogen bonds, forming chains along [100]. In the crystal of (II), there are no significant intermolecular interactions present.

Keywords

• crystal structure
• oxazepine
• benzimidazole
• angiogenesis
• natural products.