6-Amino-2-methyl-8-phenyl-1,2,3,4-tetrahydroisoquinoline-5,7-dicarbonitrile

In the title compound, C18H16N4, the dihedral angle between the benzene and phenyl rings is 61.40 (4)°. In the crystal, molecules are linked by N—H⋯N(nitrile) hydrogen bonds, forming inversion dimers. The dimers are further linked by N—H⋯N(amine) hydrogen bonds, and both units are arranged almost perpendicular to each other [angle between dimer mean planes = 84.43 (12)°]. This arrangement is extended to form a ladder-like structure parallel to the c axis.

In the title compound, C 18 H 16 N 4 , the dihedral angle between the benzene and phenyl rings is 61.40 (4) . In the crystal, molecules are linked by N-HÁ Á ÁN(nitrile) hydrogen bonds, forming inversion dimers. The dimers are further linked by N-HÁ Á ÁN(amine) hydrogen bonds, and both units are arranged almost perpendicular to each other [angle between dimer mean planes = 84. 43 (12) ]. This arrangement is extended to form a ladder-like structure parallel to the c axis.
The development of efficient synthetic methods for isoquinoline and related derivatives is continuously attracting the attention of many chemists (Rong et al., 2010;Balamurugan et al., 2011). As a part of our current studies on the development of new routes in organic synthesis and the screen of anticancer drugs, in this article, we report the crystal structure of the title compound ( Fig. 1).
The dihedral angle between the benzene and the phenyl rings is 61.40 (4)°. In the crystal ( (12)°] forming a ladder structure, that can extend into infinite sheets through the vertical direction of the step cross section. On the step cross section, the distance between the centers of two units is 6.252 (13) Å.

Experimental
Benzaldehyde (1 mmol) was added to a stirred solution of 1-methyl-4-piperidone (1 mmol) and tetrahydro pyrrole (1.2 mmol) in dichloromethane. The resulting mixture was refluxed for 4 h to obtain a α,β-unsaturated ketone as an intermediate. Subsequently, this α,β-unsaturated ketone (1 mmol) was reacted with malononitrile (2 mmol) under strong basic conditions (Rong et al., 2009), monitoring the reaction progress by TLC. After the completion of the reaction, the solvent was evaporated under reduce pressure and the crude product was purified by silica gel column chromatography.
Crystals suitable for X-ray analysis were obtained by slow evaporation of a solution in methanol and dichloromethane (4:1).

Refinement
Carbon-bound H-atoms were placed in calculated positions [C-H = 0.95-0.99 Å, U iso (H) = 1.2-1.5U eq (parent atom)] and were allowed to ride on their parent atoms. The amino-H atoms H4A and H4B were located in a difference map, and subsequently refined freely, with U iso (H) = 1.2U eq (N4).