4-(2-Nitro­benz­yl)-3-phenyl-3,4-di­hydro-2H-1,4-benzoxazin-2-ol

Louisa Chouguiat; Raouf Boulcina; Sofiane Bouacida; Hocine Merazig; Abdelmadjid Debache

doi:10.1107/S1600536814015645

. 2014 Jul 11;70(Pt 8):o863–o864. doi: 10.1107/S1600536814015645

4-(2-Nitrobenzyl)-3-phenyl-3,4-dihydro-2H-1,4-benzoxazin-2-ol

Louisa Chouguiat ^a, Raouf Boulcina ^a, Sofiane Bouacida ^b,^c,^*, Hocine Merazig ^b, Abdelmadjid Debache ^a

PMCID: PMC4158540 PMID: 25249912

Abstract

The title compound, C₂₁H₁₈N₂O₄, crystallizes with two independent molecules (A and B) in the asymmetric unit. In both molecules the oxazine ring has an envelope conformation with the hydroxyl-substituted C atom as the flap. The nitrobenzyl ring and the phenyl ring are almost normal to the mean plane of the benzooxazine ring system with dihdral angles of 85.72 (15) and 82.69 (15)°, respectively, in molecule A, and 85.79 (15) and 87.72 (15)°, respectively, in molecule B. The main difference in the conformation of the two molecules concerns the dihedral angle between the nitrobenzyl ring and the phenyl ring, viz. 79.67 (18) in molecule A and 71.13 (18)° in molecule B. In the crystal, the A and B molecules are linked by an O—H⋯O hydrogen bond. These units are then linked via C—H⋯O hydrogen bonds, forming sheets lying parallel to (010). Further C—H⋯O hydrogen bonds link the sheets to form a three-dimensional network. There are also O—H⋯π and C—H⋯π interactions present, reinforcing the three-dimensional structure.

Keywords: crystal structure

Related literature

For the preparation and applications of similar structures, see: Ozden et al. (1992 ▶); Hartenstein & Sicker (1994 ▶); Ilas et al. (2005 ▶); Touzeau et al. (2003 ▶); Torisu et al. (2004 ▶); Largeron et al. (1999 ▶).

Experimental

Crystal data

C₂₁H₁₈N₂O₄
M _r = 362.37
Orthorhombic,
a = 12.7332 (14) Å
b = 14.2777 (14) Å
c = 19.003 (2) Å
V = 3454.8 (6) Å³
Z = 8
Mo Kα radiation
μ = 0.10 mm⁻¹
T = 150 K
0.13 × 0.05 × 0.03 mm

Data collection

Bruker APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 2002 ▶) T _min = 0.860, T _max = 1.000
19156 measured reflections
3161 independent reflections
4907 reflections with I > 2σ(I)
R _int = 0.052

Refinement

R[F ² > 2σ(F ²)] = 0.043
wR(F ²) = 0.114
S = 1.04
3161 reflections
489 parameters
1 restraint
H-atom parameters constrained
Δρ_max = 0.71 e Å⁻³
Δρ_min = −0.26 e Å⁻³

Data collection: APEX2 (Bruker, 2011 ▶); cell refinement: SAINT (Bruker, 2011 ▶); data reduction: SAINT; program(s) used to solve structure: SIR2002 (Burla et al., 2003 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012 ▶) and DIAMOND (Brandenburg & Berndt, 2001 ▶); software used to prepare material for publication: WinGX publication routines (Farrugia, 2012 ▶).

Supplementary Material

Crystal structure: contains datablock(s) I. DOI: 10.1107/S1600536814015645/bq2396sup1.cif

e-70-0o863-sup1.cif^{(44.3KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536814015645/bq2396Isup2.hkl

e-70-0o863-Isup2.hkl^{(152KB, hkl)}

Click here for additional data file.^{(6.9KB, cml)}

Supporting information file. DOI: 10.1107/S1600536814015645/bq2396Isup3.cml

CCDC reference: 1012140

Additional supporting information: crystallographic information; 3D view; checkCIF report

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

Cg1 and Cg2 are the controids of the C10A–C15A and C10B–C15B rings, respectively.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O2A—H2A⋯O1B	0.82	2.06	2.843 (4)	161
C6B—H6B⋯O21A ⁱ	0.93	2.40	3.175 (5)	141
C8B—H8B⋯O1A ⁱⁱ	0.98	2.34	3.234 (4)	151
C14A—H14A⋯O2A ⁱⁱⁱ	0.93	2.57	3.177 (5)	123
C19A—H19A⋯O21B ^iv	0.93	2.45	3.134 (4)	131
C19B—H19B⋯O22A ^v	0.93	2.47	3.057 (5)	121
O2B—H2B⋯Cg1ⁱⁱ	0.82	2.69	3.484 (3)	164
C18A—H18A⋯Cg2^iv	0.93	2.83	3.564 (4)	137
C18B—H18B⋯Cg1^v	0.93	2.94	3.601 (4)	130

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

Acknowledgments

We are grateful to all personnel of the Laboratoire de Synthèse des Molécules d’Intérêts Biologiques and UR–CHEMS, Université Constantine 1, Algeria, for their assistance. Thanks are due to the MESRS (Ministère de l’Enseignement Supérieur et de la Recherche Scientifique, Algeria) for financial support.

supplementary crystallographic information

S1. Comment

Numerous natural and synthetic substances that have the core "1,4-benzoxazine" have been used in different fields of medicine. The 1,4-benzoxazine structure is an integral part of several naturally occurring substances. For example, various glycosides of the 2-hydroxy-2H-1,4-benzoxazine skeletons have been found to occur in gramineous plants such as maize, wheat, rye, and rice, and have been suggested to act as plant resistance factors against microbial diseases and insects (Ozden et al., 1992; Hartenstein & Sicker, 1994). Moreover, 3,4-Dihydro-2H-1,4-benzoxazines have received a great deal of attention due to their wide range of biological and therapeutical properties (Ilas et al., 2005). For example they have been investigated as antihypertensive agents (Touzeau et al., 2003), neuroprotective antioxidants (Largeron et al., 1999) and prostaglandin D 2 receptor antagonists (Torisu et al., 2004). Herein, we report our results about the synthesis and the crystallographic study of 4-(2-nitrobenzyl)-3-phenyl-3,4-dihydro-2H-benzo[b][1,4]oxazin-2-ol, (I). The molecular geometry and the atom-numbering scheme of asymetric unit are shown in Fig. 1. The asymetric unit contents two molecule of (I). The crystal packing can be described as alternating connected layers parallel to the (001) plane along the c axis (Fig. 2) It is stabilized by intra et intermolecular O—H···O and C—H···O hydrogen bond and O—H···π interactions (Table 1; Fig. 2). These interactions link the molecules within the layers and also link the layers together and reinforcing the cohesion of the structure.

S2. Experimental

A mixture of 4-methyl-2-(2-nitrobenzylamino)phenol (1 mmol), boronic acid (1 mmol) and glyoxal (1 mmol) in methanol (5 ml) was stirred at room temperature for 24 h. The solvent was removed in vacuo to give crude producs, which was purified by flash chromatography (silica gel, dichloromethane). Spectroscopic data for the major isomer are given below. IR (KBr): ν: 3429, 2920, 1608, 1512, 1250, 1036 cm-1. 1H NMR (250 MHz, CDCl3, J Hz) δ: 8.09 (d, 1H, J=7.5 Hz, CH arom); 7.91 (d, 1H, J=7.5 Hz, CH arom.); 7.56 (t, 1H, J=7.5 Hz, CH arom.); 7.42 (t, 1H, J=7.5 Hz, CH arom); 7.33–7.30 (m, 3H, CH arom.); 7.21–7.18 (m, 2H, CH arom.); 6.92–6.83 (m, 2H, H arom.); 6.74–6.67 (m, 1H, CH arom.); 6.45 (d, 1H, J= 7.5 Hz, CH arom.); 5.60 (s, 1H, H2); 5.06 (d, 1H, J= 18.5 Hz, Hb); 4.62 (d, 1H, J=18.5 Hz, Ha); 4.51 (s, 1H, H3); 3.26 (s, 1H, OH). 13 C NMR (62.9 MHz, CDCl3) δ: 148.1; 141.1; 139.7; 138.3; 134.1; 134.0; 133.7; 129.0; 130.0; 128.3; 128.0; 126.9; 125.3; 122.9; 117.9; 117.5; 110.6; 92.7; 64.3; 50.2. HRMS: (M+H)+, found 363.1347, C₂₁H₁₉N₂O₄ requires 363.1345.