4-[(5-Bromo-2-hydroxy­benzyl­idene)amino]-N-(4,6-dimethyl­pyrimidin-2-yl)benzene­sulfonamide–4-bromo-2-[(E)-({4-[(4,6-dimethyl­pyrimidin-2-yl)sulfamo­yl]phen­yl}iminio)meth­yl]phenolate [0.61 (7)/0.39 (7)]

Hazoor A Shad; M Nawaz Tahir; Zahid H Chohan

doi:10.1107/S1600536808041214

. 2008 Dec 13;65(Pt 1):o98–o99. doi: 10.1107/S1600536808041214

4-[(5-Bromo-2-hydroxybenzylidene)amino]-N-(4,6-dimethylpyrimidin-2-yl)benzenesulfonamide–4-bromo-2-[(E)-({4-[(4,6-dimethylpyrimidin-2-yl)sulfamoyl]phenyl}iminio)methyl]phenolate [0.61 (7)/0.39 (7)]

Hazoor A Shad ^a, M Nawaz Tahir ^b,^*, Zahid H Chohan ^a

PMCID: PMC2968005 PMID: 21581736

Abstract

The title compound, 0.61C₁₉H₁₇BrN₄O₃S·0.39C₁₉H₁₇BrN₄O₃S, is a Schiff base derived from 5-bromosalicylaldehyde and 4-amino-N-(4,6-dimethyl-2-pyrimidinyl)benzenesulfonamide(sulfamethazine) and is isostructural with its chloro analogue. The geometry of the title molecule points to the enol (OH—C=C—C=N) form as the major tautomer, however two electron-density maxima corresponding to the H atoms of the OH and NH groups, found in the region of a strong intramolecular N⋯H⋯O hydrogen bond, do not allow the elimination of the presence of the zwitterionic (O⁻—C=C—C=NH⁺) form in the crystal. Refinement of the occupancies of these H atoms gave a 0.61 (7):0.39 (7) ratio of the enolic and zwitterionic forms. The two benzene rings within the molecule are nearly coplanar and the central benzene ring forms a dihedral angle of 84.1 (1)° with the pyrimidine fragment. An intermolecular N—H⋯O hydrogen bond links molecules into chains extended along the a axis and a C—H⋯O link is also present. The H atoms of one of the methyl groups are disordered over two sites with an occupancy ratio of 0.72 (7):0.28 (7).

Related literature

For the crystal structures of similar sulphonamides, see: Chohan et al. (2008a ▶,b ▶); Shad et al. (2008 ▶); Tahir et al. (2008 ▶).

Experimental

Crystal data

0.61C₁₉H₁₇BrN₄O₃S·0.39C₁₉H₁₇BrN₄O₃S
M _r = 461.34
Orthorhombic,
a = 11.7919 (9) Å
b = 13.9965 (8) Å
c = 23.5117 (17) Å
V = 3880.5 (5) Å³
Z = 8
Mo Kα radiation
μ = 2.26 mm⁻¹
T = 296 (2) K
0.20 × 0.16 × 0.14 mm

Data collection

Bruker KAPPA APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2005 ▶) T _min = 0.650, T _max = 0.725
19597 measured reflections
3428 independent reflections
1961 reflections with I > 2σ(I)
R _int = 0.081

Refinement

R[F ² > 2σ(F ²)] = 0.048
wR(F ²) = 0.131
S = 1.00
3428 reflections
257 parameters
H-atom parameters constrained
Δρ_max = 0.35 e Å⁻³
Δρ_min = −0.65 e Å⁻³

Data collection: APEX2 (Bruker, 2007 ▶); cell refinement: SAINT (Bruker, 2007 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997 ▶) and PLATON (Spek, 2003 ▶); software used to prepare material for publication: WinGX publication routines (Farrugia, 1999 ▶) and PLATON.

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808041214/gk2160sup1.cif

e-65-00o98-sup1.cif^{(21.3KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808041214/gk2160Isup2.hkl

e-65-00o98-Isup2.hkl^{(164.8KB, 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
N1—H1N⋯O1	1.06	1.73	2.530 (5)	129
O1—H1O⋯N1	0.86	1.94	2.530 (5)	124
N2—H2N⋯O1ⁱ	0.86	2.20	2.871 (4)	135
C9—H9⋯O2ⁱⁱ	0.93	2.50	3.417 (5)	169

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

Acknowledgments

The authors acknowledge the Higher Education Commission, Islamabad, Pakistan, for funding the purchase of the diffractometer at GCU, Lahore.

supplementary crystallographic information

Comment

As a result of vital pharmacological effects of sulfonamide and their derivatives, there is a rising attention in synthesizing and biotesting of these derivatives. In the vision of the versatile biological chemistry of sulfonamides, we have synthesized and recently published the crystal structures of several compounds from this group (Chohan et al., 2008a, 2008b; Shad et al., 2008; Tahir et al., 2008). In the same continuation, we herein report the structure of the title compound.

The title compound (I) (Fig. 1) was prepared from sulfamethazine and 5-bromosalicylaldehyde. The crystal of the title compound is isostructural with 4-(5-chloro-2-hydroxybenzylideneamino)-N-(4,6-dimethylpyrimidin-2-yl)benzenesulfonamide (II) (Chohan et al., 2008b). In the crystal two tautomers, enolic and zwitterionic, with an approximate ratio of 3:2 coexists, as shown by the refinement of H atom occupancies from the N-H and O-H groups.

We shall restrict discussion to comparison of the bond geometry between (I) and (II). The longest bond in the molecule is C3—Br1, having bond distance 1.890 (5) Å. The bond distances in (I), S1—N2 [1.629 (4) Å] and S1—C11 [1.753 (4) Å] remain equal within experimental errors with those observed in (II). The range of S—O [1.416 (3)–1.431 (3) Å] bond lengths is increased compared to 1.422 (2)–1.4282 (19) Å in (II). The bond angles around the S1-atom are slightly changed. The geometry of intramolecular as well as intermolecular H-bonding is given in Table 1 and shown in Fig 2.

Experimental

Sulfamethazine (0.5566 g, 2 mmol) in ethanol (15 ml) was reacted with ethanolic (10 ml) solution of 5-bromosalicylaldehyde (0.4020 g, 2 mmol). The mixture was refluxed for 3 h. The colour of the solution gradually changed from colourless to orange-red. The solution was then cooled to room temperature, filtered and volume reduced to about one-third on rotary evaporator. After 12 days crystals of the title compound were obtained.