Ethyl 3-methyl-4-oxo-4,5-dihydro-1H-pyrrolo[2,3-d]pyridazine-2-carboxyl­ate

Shi-Quan Chen; Kai Jiang; Shi-Fan Wang

doi:10.1107/S1600536809055081

. 2010 Jan 9;66(Pt 2):o259. doi: 10.1107/S1600536809055081

Ethyl 3-methyl-4-oxo-4,5-dihydro-1H-pyrrolo[2,3-d]pyridazine-2-carboxylate

Shi-Quan Chen ^a, Kai Jiang ^b, Shi-Fan Wang ^c,^a,^*

PMCID: PMC2979812 PMID: 21579701

Abstract

The title compound, C₁₀H₁₁N₃O₃, was synthesized by the reaction of 3,5-bis(ethoxycarbonyl)-2-formyl-4-methyl-1H-pyrrole and hydrazine hydrate. The angle between the pyrrole ring and the pyridazinone ring is 0.93 (9)°. In the crystal, intermolecular N—H⋯O and N—H⋯N hydrogen-bond interactions link the molecules into a two-dimensional network.

Related literature

For the biological activity of pyrrolopyridazine compounds, see: Chen et al. (2006 ▶); Hu et al. (2004 ▶); Swamy et al. (2005 ▶). For bond-length data, see Allen et al. (1987 ▶).

Experimental

Crystal data

C₁₀H₁₁N₃O₃
M _r = 221.22
Monoclinic,
a = 8.0030 (16) Å
b = 9.774 (2) Å
c = 13.370 (3) Å
β = 90.17 (3)°
V = 1045.8 (4) Å³
Z = 4
Mo Kα radiation
μ = 0.11 mm⁻¹
T = 295 K
0.40 × 0.26 × 0.06 mm

Data collection

Bruker SMART CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ▶) T _min = 0.959, T _max = 0.994
6834 measured reflections
2045 independent reflections
1676 reflections with I > 2σ(I)
R _int = 0.031

Refinement

R[F ² > 2σ(F ²)] = 0.044
wR(F ²) = 0.120
S = 1.06
2045 reflections
156 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.27 e Å⁻³
Δρ_min = −0.21 e Å⁻³

Data collection: SMART (Bruker 2002 ▶); cell refinement: SAINT (Bruker 2002 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: PLATON (Spek, 2009 ▶); software used to prepare material for publication: SHELXTL (Sheldrick, 2008 ▶).

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536809055081/sj2715sup1.cif

e-66-0o259-sup1.cif^{(16.9KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809055081/sj2715Isup2.hkl

e-66-0o259-Isup2.hkl^{(98.5KB, 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
N3—H3⋯O1ⁱ	0.90 (3)	1.90 (3)	2.804 (2)	175 (2)
N1—H1⋯N2ⁱⁱ	0.86 (2)	2.08 (2)	2.925 (2)	166.2 (17)

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Symmetry codes: (i) Inline graphic ; (ii) .

Acknowledgments

This research was supported financially by the National Natural Science Foundation of China (30660215).

supplementary crystallographic information

Comment

Pyridazine and its derivatives play an important role play an important role in medicine and as pesticides. One of the main techniques to synthesize pyridazines is to react 1,4-dicarbonyl compounds with hydrazine hydrate. Recently, the synthesis of pyrrolopyridazine compounds has aroused great interest because of their significant biological activity (Chen et al., 2006; Hu et al., 2004; Swamy et al., 2005). As part of our work to develop new types of pyrrolopyridazine compounds with potential biological activity, we report here the synthesis and structure of the title compound (1). In the molecule of compound (1), the torsion angles are N1—C1—C2—C3 179.21 (14) and N1—C1—C2—C5 0.20 (18)°. The dihedral angle between the pyrrole and pyridazinone rings is 0.93 (9)°, an indication that the pyrrolopyridazine system is reasonably planar. The C4═N2 and C3═O1 bond lengths in the molecule are 1.291 (2) and 1.2397 (19)°, respectively, showing their double-bond character (Allen et al., 1987). In the crystal structure, N—H···O and N—H···N hydrogen bonds form a two-dimensional network structure, Fig. 2.

Experimental

2.39 g (10 mmol) of the 3,5-bis(ethoxycarbonyl)-2,4- dimethyl-1(H)-pyrrole was added to a mixed solvent of 60 ml THF and 60 ml glacial acetic acid at room temperature under stirring until all of the solid was dissolved. Then, 60 ml water and 21.93 g (40 mmol) cerous ammonium nitrate (CAN) were added consecutively and the mixture stirred at room temperature for 1.5 h until the reaction was complete. The reaction mixture was poured into ice water and the white solid was separated (2.13 g, 84%). Recrystallization of the white solid from ethanol gave the compound 3,5-bis(ethoxycarbonyl)-2-formyl-4-methyl-1(H)-pyrrole.

An aqueous solution of hydrazine hydrate (80%, 0.5 ml) was added into a solution of 3,5-bis(ethoxycarbonyl)-2-formyl-4-methyl- 1(H)-pyrrole (0.25 g, 1.0 mmol) in glacial acetic acid (20 ml) under stirring at room temperature. The reaction mixture was refluxed for 3 h till the reaction was complete. The reaction mixture was evaporated to remove the solvent of water and acetic acid at reduced pressure to yield the title compound (1) as a white solid (0.18 g, 82%). Recrystallization of the white solid from hot ethanol yielded colorless plate-like crystals suitable for X-ray diffraction analysis.