Crystal structures of two new isocoumarin derivatives: 8-amino-6-methyl-3,4-diphenyl-1H-isochromen-1-one and 8-amino-3,4-diethyl-6-methyl-1H-isochromen-1-one

Abstract

The title compounds, 8-amino-6-methyl-3,4-diphenyl-1H-isochromen-1-one, C22H17NO2, (I), and 8-amino-3,4-diethyl-6-methyl-1H-isochromen-1-one, C14H17NO2, (II), are new isocoumarin derivatives in which the isochromene ring systems are planar. Compound II crystallizes with two independent molecules (A and B) in the asymmetric unit. In I, the two phenyl rings are inclined to each other by 56.41 (7)° and to the mean plane of the 1H-isochromene ring system by 67.64 (6) and 44.92 (6)°. In both compounds, there is an intramolecular N—H...O hydrogen bond present forming an S(6) ring motif. In the crystal of I, molecules are linked by N—H...π interactions, forming chains along the b-axis direction. A C—H...π interaction links the chains to form layers parallel to (100). The layers are then linked by a second C—H...π interaction, forming a three-dimensional structure. In the crystal of II, the two independent molecules (A and B) are linked by N—H...O hydrogen bonds, forming –A–B–A–B– chains along the [101] direction. The chains are linked into ribbons by C—H...π interactions involving inversion-related A molecules. The latter are linked by offset π–π interactions [intercentroid distances vary from 3.506 (1) to 3.870 (2) Å], forming a three-dimensional structure.

Keywords

• crystal structure
• chromen
• isochromene
• hydrogen bonding
• N—H...π interactions
• C—H...π interactions
• offset π—π interactions
• Hirshfeld surface analysis