N′-Acetyl-5-amino-1-methyl-1H-pyrazole-4-carbohydrazonamide dihydrate

Anna V Dolzhenko; Anton V Dolzhenko; Geok Kheng Tan; Lip Lin Koh; Giorgia Pastorin

doi:10.1107/S1600536810015357

. 2010 Apr 30;66(Pt 5):o1209–o1210. doi: 10.1107/S1600536810015357

N′-Acetyl-5-amino-1-methyl-1H-pyrazole-4-carbohydrazonamide dihydrate

Anna V Dolzhenko ^a,^*, Anton V Dolzhenko ^a, Geok Kheng Tan ^b, Lip Lin Koh ^b, Giorgia Pastorin ^a

PMCID: PMC2979283 PMID: 21579239

Abstract

In the title compound, C₇H₁₂N₆O·2H₂O, the Z configuration of the hydrazone fragment is stabilized by an intramolecular N—H⋯N hydrogen bond involving one of the amino groups. In the crystal structure, the hydrazonamide molecules are connected via intermolecular N—H⋯O=C hydrogen bonds, forming C(7) chains running along [010]. The chains form sheets parallel to the ( Inline graphic 01). The chains are cross-linked by water molecules to form a three-dimensional hydrogen-bonded network.

Related literature

For bioactive pyrazoles, see: Elguero et al. (2002 ▶); Lamberth (2007 ▶). For the use of pyrazoles as synthons in heterocyclic chemistry, see: Schenone et al. (2007 ▶); Dolzhenko et al. (2008 ▶). For the use of pyrazoles in metal-organic chemistry, see: Mukherjee (2000 ▶); Halcrow (2009 ▶). For the crystal structures of related 5-amino-1H-pyrazole-4-carboxylic acid derivatives, see: Zia-ur-Rehman et al. (2008 ▶, 2009 ▶); Caruso et al. (2009 ▶). For the crystal structure of N′-acetyl-2-phenylethanehydrazonamide, see: Ianelli et al. (2001 ▶). For the graph-set analysis of hydrogen bonding, see: Bernstein et al. (1995 ▶).

Experimental

Crystal data

C₇H₁₂N₆O·2H₂O
M _r = 232.26
Triclinic,
a = 7.5496 (9) Å
b = 7.6208 (9) Å
c = 11.2518 (13) Å
α = 102.645 (2)°
β = 101.440 (2)°
γ = 110.810 (2)°
V = 562.75 (11) Å³
Z = 2
Mo Kα radiation
μ = 0.11 mm⁻¹
T = 223 K
0.45 × 0.12 × 0.10 mm

Data collection

Bruker SMART APEX CCD diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 2001 ▶) T _min = 0.953, T _max = 0.989
3963 measured reflections
2548 independent reflections
2174 reflections with I > 2σ(I)
R _int = 0.021

Refinement

R[F ² > 2σ(F ²)] = 0.052
wR(F ²) = 0.141
S = 1.05
2548 reflections
183 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.31 e Å⁻³
Δρ_min = −0.26 e Å⁻³

Data collection: SMART (Bruker, 2001 ▶); cell refinement: SAINT (Bruker, 2001 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXTL.

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536810015357/ci5086sup1.cif

e-66-o1209-sup1.cif^{(16.9KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810015357/ci5086Isup2.hkl

e-66-o1209-Isup2.hkl^{(125.1KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O2W—H4W⋯N1ⁱ	0.87 (3)	2.04 (3)	2.884 (2)	162 (3)
O2W—H3W⋯O1	0.86 (3)	2.11 (3)	2.885 (2)	150 (3)
O1W—H2W⋯O2Wⁱⁱ	0.89 (3)	1.93 (3)	2.824 (2)	175 (3)
O1W—H1W⋯N5	0.81 (3)	2.24 (3)	2.982 (2)	153 (3)
N6—H6N⋯O1Wⁱⁱⁱ	0.84 (2)	2.07 (2)	2.905 (2)	177 (2)
N4—H42⋯O1Wⁱⁱⁱ	0.88 (2)	2.14 (3)	2.995 (2)	165 (2)
N4—H41⋯O1^iv	0.81 (2)	2.08 (2)	2.874 (2)	169 (2)
N3—H32⋯N5	0.86 (2)	2.18 (2)	2.791 (2)	128 (2)
N3—H31⋯O2W^v	0.83 (2)	2.27 (2)	3.082 (2)	163 (2)

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) ; (iv) ; (v) .

Acknowledgments

This work was supported by the National Medical Research Council, Singapore (grant No. NMRC/NIG/0020/2008).

supplementary crystallographic information

Comment

Pyrazoles have been well recognized as valuable ligands in metal-organic chemistry (Mukherjee, 2000; Halcrow, 2009). Pyrazoles also possess useful agricultural (Lamberth, 2007) and pharmacological (Elguero et al., 2002) properties and serve as synthons for other pyrazolo fused bioactive heterocycles (Schenone et al., 2007; Dolzhenko et al., 2008).

Herein, we report molecular and crystal structure of N'-acetyl-5-amino-1-methyl-1H-pyrazole-4-carbohydrazonamide (Figs. 1 and 2). The compound can exist in two tautomeric forms, namely hydrazonamide and imidohydrazide (Fig. 3). The hydrazonamide tautomer can also exhibit (E-Z) isomerism by inversion of configuration of the hydrazono C═N linkage. We found that the compound crystallizes as a N'-acetyl-5-amino-1-methyl-1H-pyrazole-4-carbohydrazonamide tautomer. Similarly to previously reported N'-acetyl-2-phenylethanehydrazonamide (Ianelli et al., 2001), the hydrazonamide group of N'-acetyl-5-amino-1-methyl-1H-pyrazole-4-carbohydrazonamide adopts (Z)-configuration. This configuration is stabilized by the intramolecular N(3)H···N5═C5 hydrogen bonding between the amino group and the hydrazone N5 atom, generating an S(6) graph-set motif (Bernstein et al., 1995). Similar NH···O═C interactions were reported for the structurally related derivatives of 5-amino-1H-pyrazole-4-carboxylic acid (Zia-ur-Rehman et al., 2008; Zia-ur-Rehman et al., 2009; Caruso et al., 2009). Planarity of the molecule is affected by slight twisting of the acetyl group [C5—N5—N6—C6 torsion angle is 170.14 (16)°].

In the crystal, the hydrazonamide molecules are arranged to form sheets parallel to the (101) (Fig. 2). In the sheets, atom N4 of one molecule is involved in a intermolecular N—H···O═C interaction with the carbonyl atom O1 of adjacent molecule making C(7) chains along the [010] direction. The water molecules further stabilize packing by formation of the intermolecular hydrogen bond network (Fig. 2 and Table 1).

Experimental

N'-Acetyl-5-amino-1-methyl-1H-pyrazole-4-carbohydrazonamide was prepared by treatment of ethyl N-(4-cyano-1-methyl-1H-pyrazol-5-yl)acetimidate with 3 eq. of hydrazine hydrate (40%) in ethanol. Detail procedure with proposed mechanism will be reported elsewhere. Single crystals suitable for the crystallographic analysis were grown by recrystallization from ethanol, m.p. 513 K.