2-Cyclopentylidenehydrazinecarboxamide

The asymmetric unit of the title compound, C6H11N3O, consists of two independent molecules in which the cyclopentane rings adopt envelope conformations with CH2 grouping as the flap and the semicarbazone groups are essentially planar, with maximums deviation of 0.0311 (12) and 0.0285 (12) Å. In the crystal, N—H⋯O, N—H⋯N and C—H⋯O hydrogen bonds link the molecules to form sheets lying parallel to the ab plane.

The asymmetric unit of the title compound, C 6 H 11 N 3 O, consists of two independent molecules in which the cyclopentane rings adopt envelope conformations with CH 2 grouping as the flap and the semicarbazone groups are essentially planar, with maximums deviation of 0.0311 (12) and 0.0285 (12) Å . In the crystal, N-HÁ Á ÁO, N-HÁ Á ÁN and C-HÁ Á ÁO hydrogen bonds link the molecules to form sheets lying parallel to the ab plane.

2-Cyclopentylidenehydrazinecarboxamide
Hoong-Kun Fun, Wan-Sin Loh, Mahesh Padaki, Arun M. Isloor and Nishitha A. Isloor Comment Various semicarbazones, have been known to possess biological activities against many of the most common species of bacteria (Dogan et al., 1999). Semicarbazones are of much interest due to their wide spectrum of antibacterial activities (Pandeya & Dimmock, 1993). Recently some workers reviewed the bioactivity of semicarbazones and they have exhibited anticonvulsant (Pandeya et al., 1998;Yogeeswari et al., 2004) and antitubercular  properties. Our previous report highlights the synthesis and crystal structures of the semicarbozones (Fun et al., 2011). In continuation of our studies in this area, we now report the synthesis and structure of the title compound.

Experimental
Semicarbazide hydrochloride (0.66 g, 0.0059 mol) and freshly recrystallized sodium acetate (0.58 g, 0.007 mol) were dissolved in water (10 ml) following a literature procedure (Furniss et al., 1978). The reaction mixture was stirred at room temperature for 10 minutes. To this, cyclopentanone (0.5 g, 0.0059 mol) was added and shaken well. A little alcohol was added to dissolve the turbidity. It was shaken for 10 more minutes and allowed to stand. The semicarbazone crystallized on standing for 6 h. The separated crystals were filtered, washed with cold water and recrystallized from ethanol as colourless plates. M.p. 495-498 K.

Refinement
N-bound H atoms were located from the difference Fourier map and were refined freely [N-H = 0.858 (18) to 0.926 (19) Å]. The remaining H atoms were located geometrically and were refined using a riding model with U iso (H) = 1.2 U eq (C) [C-H = 0.99 Å]. In the final refinement, one outliner was omitted, 6 11 8.

2-Cyclopentylidenehydrazinecarboxamide
Crystal data 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 > σ(F 2 ) is used only for calculating R-factors(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.