2-(4-Amino-5-thioxo-4,5-dihydro-1H-1,2,4-triazol-3-ylmethyl)isoindoline-1,3-dione

The title compound, C11H9N5O2S, was synthesized from N-phthaloylglycine and thiocarbohydrazide by the fusion method. This is the first report of a triazole derivative of N-phthaloylglycine. The title compound exists in the thione form. The molecule is non-planar, with a dihedral angle between the isoindoline ring system and the triazole ring system of 82.24 (5)°. The crystal structure is stabilized by intermolecular hydrogen bonding linking the molecules into a three-dimensional network.

The title compound, C 11 H 9 N 5 O 2 S, was synthesized from N-phthaloylglycine and thiocarbohydrazide by the fusion method. This is the first report of a triazole derivative of Nphthaloylglycine. The title compound exists in the thione form. The molecule is non-planar, with a dihedral angle between the isoindoline ring system and the triazole ring system of 82.24 (5) . The crystal structure is stabilized by intermolecular hydrogen bonding linking the molecules into a threedimensional network.
Among the N-phthaloylamino acids, N-phthaloylglycine has been the most widely studied. Such studies include cleavage of N-phthaloylglycine with various amines (Khan & Ismail, 2002), metal complexes with interesting supramolecular structures (Barooah et al., 2006b) and adduct formation of N-phthaloylglycine with various aromatic amines and hydroxyl-aromatics (Barooah et al., 2006a). The heterocyclic derivatives of N-phthaloylglycine are also reported in literature such as oxadiazole (Antunes et al., 1998) and benzoxazinone (Shariat & Abdollahi, 2004). Keeping in view the importance of structural and biological aspects of N-phthaloylamino acids, the present work is aiming to incorporate 1,2,4-triazole ring with N-phthaloylglycine moiety. To the best of our knowledge this is the first crystal structure report on the 1,2,4-triazole derivative of N-phthaloylglycine.
The crystallographic analysis demonstrates that the title compound (I) exists as the thione form rather than the thiol as shown in scheme 1 and Fig. 1 (Allen et al., 1987)] among which the N2-C11 bond length is slightly longer than that of N3-C11 (Wang et al., 1998). The NN bond lengths and all bond angles in triazole ring show no significant difference when compared to analogous compounds.
The phthalimide is also planar and all bond lengths and angles in the phthalimide ring are within normal ranges (Ng, 1992). The dihedral angle between the isoindoline and triazole ring systems is 82.24 (5)°, indicating the nonplanarity of the molecule as a whole.

Experimental
The title compound (I) was synthesized by the reaction of N-phthaloylglycine and thiocarbohydrazide by the fusion method.
A mixture of N-phthaloylglycine (0.01 mol) and thiocarbohydrazide (0.01 mol) contained in a round bottom flask was heated until the contents melted. The mixture was kept at this temperature for 25-30 min. after cooling to room temperature the sup-2 mixture was triturated with methanol and the solid obtained was filtered, washed with methanol and recrystallized from a mixture (1:1) of ethanol and acetonitrile to obtain suitable crystals for x-ray analysis.

Refinement
H atoms bonded to C were included in calculated positions with C-H distances ranging from 0.95-0.99 Å and U eq 1.2 times those of the parent atoms; those bonded to N were found by difference Fourier techniques and refined isotropically.