3-Methyl-1,2,4-triazolo[3,4-a]phthalazine monohydrate

Grzegorz Dutkiewicz; C S Chidan Kumar; H S Yathirajan; A N Mayekar; Maciej Kubicki

doi:10.1107/S1600536809040677

. 2009 Oct 10;65(Pt 11):o2694. doi: 10.1107/S1600536809040677

3-Methyl-1,2,4-triazolo[3,4-a]phthalazine monohydrate

Grzegorz Dutkiewicz ^a, C S Chidan Kumar ^b, H S Yathirajan ^b, A N Mayekar ^c, Maciej Kubicki ^a,^*

PMCID: PMC2971311 PMID: 21578298

Abstract

In the crystal structure of the title compound, C₁₀H₈N₄·H₂O, the organic molecules are approximately planar [maximum deviation from the least-squares plane = 0.041 (2) Å]. Two molecules are connected by two water molecules via O—H⋯N hydrogen bonding into dimers, which are located around centres of inversion. In the crystal, molecules are stacked in the a-axis direction, with mean distances between the π systems of 3.43 (1) and 3.46 (1) Å [centroid–centroid distances are 3.604 (2) and 3.591 (2) Å].

Related literature

For general background to phthalazines, see: Cheng et al. (1999 ▶); Coates (1999 ▶); De Stevens (1981 ▶); Shubin et al. (2004 ▶); Tarzia et al. (1989 ▶); Yatani et al. (2001 ▶). For related structures, see: Boulanger et al. (1991 ▶); Burton-Pye et al. (2005 ▶); Zimmer et al. (1995 ▶). For a description of the Cambridge Structural Database, see: Allen (2002 ▶).

Experimental

Crystal data

C₁₀H₈N₄·H₂O
M _r = 202.22
Triclinic,
a = 7.3009 (9) Å
b = 7.9253 (9) Å
c = 9.2755 (10) Å
α = 109.663 (10)°
β = 104.91 (1)°
γ = 95.830 (9)°
V = 477.83 (10) Å³
Z = 2
Cu Kα radiation
μ = 0.80 mm⁻¹
T = 295 K
0.4 × 0.2 × 0.1 mm

Data collection

Oxford Diffraction SuperNova (single source at offset) Atlas diffractometer
Absorption correction: multi-scan (CrysAlis Pro; Oxford Diffraction, 2009 ▶) T _min = 0.831, T _max = 0.932
2893 measured reflections
1772 independent reflections
1615 reflections with I > 2σ(I)
R _int = 0.024

Refinement

R[F ² > 2σ(F ²)] = 0.057
wR(F ²) = 0.147
S = 1.12
1772 reflections
164 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.20 e Å⁻³
Δρ_min = −0.17 e Å⁻³

Data collection: CrysAlis Pro (Oxford Diffraction, 2009 ▶); cell refinement: CrysAlis Pro; data reduction: CrysAlis Pro; program(s) used to solve structure: SIR92 (Altomare et al., 1993 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: XP (Siemens, 1989 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809040677/nc2160sup1.cif

e-65-o2694-sup1.cif^{(16KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809040677/nc2160Isup2.hkl

e-65-o2694-Isup2.hkl^{(85.5KB, 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
O1W—H1W2⋯N1	0.92 (5)	2.08 (5)	2.987 (2)	168 (4)
O1W—H1W1⋯N2ⁱ	0.83 (3)	2.21 (3)	3.043 (2)	177 (3)

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Symmetry code: (i) Inline graphic .

Acknowledgments

CSC thanks the University of Mysore for research facilities.

supplementary crystallographic information

Comment

The practical interest upon phthalazine derivatives is based on their widespread applications (Coates, 1999). They are commonly used as ligands in transition metal catalysis (e.g., Yatani et al., 2001), as chemiluminescent materials (Shubin et al., 2004) and for optical applications (Cheng et al., 1999). The chemistry of phthalazine derivatives has been of increasing interest since many of these compounds have found chemotherapeutic applications, especially as antihypertensive agents (De Stevens, 1981). 3-substituted 1,2,4-triazolo[3,4-a]phthalazines have been described as high affinity ligands for benzodiazepine receptor site (e.g., Tarzia et al., 1989).

In the Cambridge Database (Allen, 2002; ver. 5.30, November 2008) there are only four structures with 1,2,4-triazolo[3,4-a]phthalazine units. This includes 3-chloromethyl-1,2,4-triazolophthalazine (Burton-Pye et al., 2005), 3-(p-methoxyphenyl)triazolo(4,3 - a)phthalazine (Boulanger et al., 1991), 3-(p-methoxyphenyl)-6-(N,N-bis(2-methoxyethyl)amino)triazolo(4,3 - a)phthalazine (Boulanger et al., 1991), and 3-butyl-s-triazolo(3,4 - a)phthalazine (Zimmer et al., 1995). Here we present the X-ray structural analysis of the hydrate of 3-methyl[1,2,4]triazolo[3,4-a]phthalazine.

The molecules are almost planar with maximum deviation from the least-squares plane through all 13 ring atoms of 0.041 (2) Å (Fig. 1). The dihedral angle between the planes of the phenyl and the 1,2,4-triazole rings amount to 2.84 (7)°.

In the crystal the principal motif is built of two molecules of 3-methyl[1,2,4]triazolo[3,4-a]phthalazine and two water molecules, which are connected by means of O—H···N hydrogen bonds into centrosymmetric dimers which can be described according to the graph set notation as R₄⁴(10), cf. (Fig. 2). The planar molecules are stacked in a head-to-tail manner in the direction of the crystallographic a-axis with distances between the subsequent mean planes of 3.43 (1)Å and 3.46 (1)Å.

Experimental

1-Hydrazinophthalazine (2 g, 12.5 mmol) in 10 ml acetic acid was refluxed for 4 h. The reaction mixture was quenched to ice cold water and the solid separated was collected by filteration. The solid obtained was crystallized from methanol. Crystals for x-ray measurements were grown by a slow evaporation of ethyl acetate solution (m.p.: 421–423 K).