(E)-2-(4-Methylbenzylidene)hydrazinecarboxamide

The title compound, C9H11N3O, was synthesized by the reaction of 4-methylbenzaldehyde with semicarbazide. The molecule adopts an E configuration about the central C=N double bond and the dihedral angle between the mean planes of the benzene ring and the carboxamide groups is 17.05 (9)°. The hydrazine N atoms are twisted slightly out of the plane of the carboxamide group [C—C—N—N torsion angle = 178.39 (14)°] and an intramolecular N—H⋯N bond generates an S(5) ring. In the crystal, adjacent molecules are connected via a pair of N—H⋯O hydrogen bonds, generating R 2 2(8) loops, resulting in supramolecular [001] ribbons.

The title compound, C 9 H 11 N 3 O, was synthesized by the reaction of 4-methylbenzaldehyde with semicarbazide. The molecule adopts an E configuration about the central C N double bond and the dihedral angle between the mean planes of the benzene ring and the carboxamide groups is 17.05 (9) . The hydrazine N atoms are twisted slightly out of the plane of the carboxamide group [C-C-N-N torsion angle = 178.39 (14) ] and an intramolecular N-HÁ Á ÁN bond generates an S(5) ring. In the crystal, adjacent molecules are connected via a pair of N-HÁ Á ÁO hydrogen bonds, generating R 2 2 (8) loops, resulting in supramolecular [001] ribbons.

Comment
Schiff bases are formed from the reaction of a primary amine with aldehydes or ketones. They exhibit interesting biological activities, such as antifungal, antibacterial, antimalarial, antiproliferative, anti-inflammatory, antiviral and antipyretic properties (Dhar et al., 1982;Przybylski et al., 2009). The Imine functional group present in these compounds is responsible for their vast biological activities. In addition, Schiff bases are also employed as intermediates in the total synthesis of bioactive natural products (Bringmann et al., 2004;De Souza et al., 2007;Guo et al., 2007).
The asymmetric unit of the title compound is shown in Fig In the crystal packing (Fig. 2), the adjacent molecules are connected via pair of N-H···O hydrogen bonds, generating an R 2 2 (8) ring motifs, resulting in supramolecular ribbons along the c-axis.

Experimental
A mixture of 4-methylbenzaldehyde (0.1 g, 0.83 mmol) and semicarbazide (0.062 g, 0.83 mmol) was dissolved in ethanol (5.0 ml) and water (1.0 ml) which was then refluxed in the presence of sodium hydroxide (0.25M) for 3-4 hours. After completion of the reaction (through TLC monitoring), the mixture was poured into ice. The precipitate which was formed was filtered and washed with water. The pure solid was then recrystallised from ethanol to afford the title compound as colourless plates.

Refinement
Atoms H1N2 and H1N3 were located from a difference Fourier map and refined freely [N-H = 0.93 (2)-0.97 (2)    Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > 2σ(F 2 ) is used only for calculating Rfactors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.