Crystal structure of 6-(p-tolyl)benzo[b]naphtho[2,3-d]thiophene and of an orthorhombic polymorph of 7-phenylanthra[2,3-b]benzo[d]thiophene

The title compounds, C23H16S, (I), and C26H16S, (II), are benzothiophene derivatives in which the benzothiophene moiety is fused with a naphthalene ring system in (I), and with an anthracene ring system in (II). In (I), the mean plane of the benzothiophene ring system makes a dihedral angle of 2.28 (6)° with the naphthalene ring system, and a dihedral angle of 1.28 (6)° with the anthracene ring system in (II), showing that the fused units are essentially planar. In (I), the 4-methylbenzene ring substituent makes a dihedral angle of 71.40 (9)° with the naphthalene ring system, while the phenyl ring substituent in (II) makes a dihedral angle of 67.08 (12)° with the anthracene ring system. In the crystals of both compounds, molecules are linked by C—H...π interactions, leading to the formation of slabs parallel to (001) in (I) and to zigzag chains along [001] in (II). There are also offset π–π interactions present within the slabs in (I). In the crystal of (II), they link the chains, forming sheets parallel to (010). The triclinic polymorph of compound (II) has been reported [Sivasakthikumaranet al., (2012).J. Org. Chem.77, 9053–9071].

Synthesis and ring-opening polymerization of 2-substituted 1,3-benzoxazine: the first observation of the polymerization of oxazine ring-substituted benzoxazines

2-Substituted 1,3-benzoxazines having a phenyl group as an oxazine ring substituent are synthesized with benzaldehyde through 2-hydroxy-N-phenylbenzylamine structures.