2,2′-Bis{8-[(benzyl­amino)­methyl­idene]-1,6-dihy­droxy-5-isopropyl-3-methyl­naphthalen-7(8H)-one}

Shukhrat M Hakberdiev; Samat A Talipov; Davranbek N Dalimov; Bakhtiyar T Ibragimov

doi:10.1107/S1600536813027281

. 2013 Oct 9;69(Pt 11):o1626–o1627. doi: 10.1107/S1600536813027281

2,2′-Bis{8-[(benzylamino)methylidene]-1,6-dihydroxy-5-isopropyl-3-methylnaphthalen-7(8H)-one}

Shukhrat M Hakberdiev ^a,^*, Samat A Talipov ^b, Davranbek N Dalimov ^a, Bakhtiyar T Ibragimov ^b

PMCID: PMC3884299 PMID: 24454075

Abstract

The asymmetric unit of the title compound, C₄₄H₄₄N₂O₆, contains two independent molecules with similar conformations. The dihydronaphthalene ring systems are approximately planar [maximum deviations = 0.036 (2), 0.128 (2), 0.0.24 (2) and 0.075 (2) Å]. The dihedral angle between two dihydronaphthalene ring systems is 83.37 (4)° in one molecule and 88.99 (4)° in the other. The carbonyl O atom is linked with the adjacent hydroxy and imino groups via intramolecular O—H⋯O and N—H⋯O hydrogen bonds. In the crystal, molecules are linked through O—H⋯O hydrogen bonds into layers parallel to (001), and adjacent layers are further stacked by π–π interactions between dihydronaphthalene and phenyl rings into a three-dimensional supramolecular architecture. In the crystal, one of the isopropyl groups is disordered over two positions with an occupancy ratio of 0.684 (8):0.316 (8).

Related literature

For details of extraction and synthesis of gossypol and its derivatives, see: Kenar (2006 ▶). For synthesis and biological activities, see: Polsky et al. (1989 ▶); Radloff et al. (1985 ▶). For formation of crystalline forms of inclusion compounds, see: Ibragimov & Talipov (1999 ▶, 2004 ▶). graphic file with name e-69-o1626-scheme1.jpg

Experimental

Crystal data

C₄₄H₄₄N₂O₆
M _r = 696.81
Monoclinic,
a = 9.8118 (8) Å
b = 29.014 (2) Å
c = 25.5854 (17) Å
β = 90.196 (6)°
V = 7283.6 (9) Å³
Z = 8
Cu Kα radiation
μ = 0.68 mm⁻¹
T = 293 K
0.6 × 0.3 × 0.2 mm

Data collection

Oxford Diffraction Xcalibur Ruby diffractometer
Absorption correction: multi-scan (CrysAlis PRO; Oxford Diffraction, 2009 ▶) T _min = 0.66, T _max = 0.88
54670 measured reflections
15043 independent reflections
7763 reflections with I > 2σ(I)
R _int = 0.049

Refinement

R[F ² > 2σ(F ²)] = 0.062
wR(F ²) = 0.191
S = 0.94
15043 reflections
1001 parameters
3 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.22 e Å⁻³
Δρ_min = −0.26 e Å⁻³

Data collection: CrysAlis PRO (Oxford Diffraction, 2009 ▶); cell refinement: CrysAlis PRO; data reduction: CrysAlis PRO; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: XP (Bruker, 1998 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Crystal structure: contains datablock(s) I, New_Global_Publ_Block. DOI: 10.1107/S1600536813027281/xu5738sup1.cif

e-69-o1626-sup1.cif^{(72.3KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536813027281/xu5738Isup2.hkl

e-69-o1626-Isup2.hkl^{(735.3KB, 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
N1A—H1AN⋯O3A	0.86	1.79	2.494 (3)	138
N1B—H1BN⋯O3B	0.86	1.85	2.531 (3)	135
N2A—H2AN⋯O7A	0.86	1.93	2.584 (3)	132
N2B—H2BN⋯O7B	0.86	1.89	2.561 (3)	134
O1A—H1A⋯O7B ⁱ	0.65 (2)	2.24 (3)	2.778 (3)	141 (3)
O1B—H1B⋯O7A ⁱⁱ	0.77 (3)	2.33 (3)	2.846 (2)	125 (3)
O4A—H4AB⋯O3A	0.74 (3)	2.05 (3)	2.588 (3)	130 (3)
O4B—H4BC⋯O3B	0.83 (4)	1.98 (4)	2.568 (4)	126 (4)
O5A—H5A⋯O3B	0.76 (3)	2.10 (3)	2.714 (3)	138 (3)
O5B—H5B⋯O3A	0.81 (3)	1.98 (3)	2.645 (3)	139 (3)
O8A—H8A⋯O1B ⁱⁱⁱ	0.92 (5)	2.45 (5)	3.290 (3)	151 (4)
O8A—H8A⋯O7A	0.92 (5)	1.95 (5)	2.592 (3)	126 (4)
O8B—H8B⋯O1A ^iv	0.86 (5)	2.40 (5)	3.183 (3)	151 (4)
O8B—H8B⋯O7B	0.86 (5)	1.93 (5)	2.577 (3)	130 (4)

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

Acknowledgments

We thank the Academy of Sciences of the Republic of Uzbekistan for supporting this study F7–T048

supplementary crystallographic information

1. Comment

Bis-benzylaminogossypol (2,2'-bis(1,6-dihydroxy,-5-isopropyl 8-methine-aminobenzyl-3-methylnaphthalene-7-one), C₄₄H₄₄O₆N₂) is Shiff base derivative of gossypol, a phenolic pigment extracted from cotton seeds (Kenar, 2006). Gossypol demonstrates wide range of biological activities (Polsky et al., 1989: Radloff et al., 1985) and versatile host properties (Ibragimov & Talipov, 1999; 2004). Herein, we describe the crystal structure of bis-benzylaminogossypol. The asymmetric unit of the crystal structure consists of two independent molecules A and B which are linked by a pair of strong O5A—H···O3B and O5B—H···O3A hydrogen bonds and the molecules form a dimer. Molecules of the title compound is racemic and in the enamine tautomer form. The naphthyl moieties of both molecules are planar and nearly perpendicular, the dihedral angles between their least-squares planes are 83.36 (5)° and 89.04 (5)° in the molecules A and B (Fig.1), respectively. The tilt angle between the benzyl rings and corresponding naphtyl moiety are different: (C1A—C10A)/(C31A—C37A) - 9.14 (16)°; (C11A—C20A)/(C38A—C44A) -52.66 (11)°; (C1B—C10B)/(C31B—C37B) -4.41 (14)°; (C11B—C20B)/(C38B—C44B) -65.51 (11)°. Isopropyl group (to C15A) are disordered. In the crystal structure (Fig.2), the dimers of title compound are linked through O1A—H···O7B, O1B—H···O7A, O8A—H···O1B and O8B—H···O1A hydrogen bonds into layers parallel to (0 0 1) (Table 1).

2. Experimental

Gossypol was obtained from the Experimental Plant of the Institute of Bioorganic Chemistry, Academy of Sciences of Uzbekistan where it was produced from by-products of the cottonseed oil industry. To prepare the Schiff base compound, gossypol was mixed with benzylamine in a 1:3 molar ratio in the acetone. This reaction solution was allowed to stand in the dark for 3 days, during which crystalline precipitate formed within solution. The precipitate was recovered by filtration and air-dried. Suitable crystals were selected from the precipitate and were used for diffraction without additional recrystallization.