7-Bromo-2-methyl-1-tosyl­naphtho[2,1-b]furan

Hong Dae Choi; Pil Ja Seo; Byeng Wha Son; Uk Lee

doi:10.1107/S1600536808015286

. 2008 May 24;64(Pt 6):o1158. doi: 10.1107/S1600536808015286

7-Bromo-2-methyl-1-tosylnaphtho[2,1-b]furan

Hong Dae Choi ^a, Pil Ja Seo ^a, Byeng Wha Son ^b, Uk Lee ^b,^*

PMCID: PMC2961428 PMID: 21202666

Abstract

The title compound, C₂₀H₁₅BrO₃S, was prepared by the oxidation of 7-bromo-2-methyl-1-(4-tolylsulfanyl)naphtho[2,1-b]furan with 3-chloroperoxybenzoic acid. The 4-tolyl ring makes a dihedral angle of 70.96 (6)° with the plane of the naphthofuran fragment. The crystal structure is stabilized by aromatic π–π stacking interactions, with centroid–centroid distances of 3.672 (3) and 3.858 (3) Å between the central benzene and furan rings, and between the brominated benzene and central benzene rings of the naphthofuran system of neighbouring molecules, respectively. In addition, the stacked molecules exhibit C—H⋯π and inter- and intramolecular C—H⋯O interactions.

Related literature

For the crystal structures of similar 2-methyl-1-(phenylsulfonyl)naphtho[2,1-b]furan compounds, see: Choi et al. (2008a ▶,b ▶).

Experimental

Crystal data

C₂₀H₁₅BrO₃S
M _r = 415.29
Monoclinic,
a = 14.026 (2) Å
b = 8.225 (1) Å
c = 15.185 (2) Å
β = 102.826 (2)°
V = 1708.1 (4) Å³
Z = 4
Mo Kα radiation
μ = 2.54 mm⁻¹
T = 173 (2) K
0.30 × 0.30 × 0.20 mm

Data collection

Bruker SMART CCD diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 2000 ▶) T _min = 0.480, T _max = 0.608
10014 measured reflections
3704 independent reflections
3368 reflections with I > 2σ(I)
R _int = 0.024

Refinement

R[F ² > 2σ(F ²)] = 0.032
wR(F ²) = 0.082
S = 1.09
3704 reflections
228 parameters
H-atom parameters constrained
Δρ_max = 0.61 e Å⁻³
Δρ_min = −1.04 e Å⁻³

Data collection: SMART (Bruker, 2001 ▶); cell refinement: SAINT (Bruker, 2001 ▶); 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 (Farrugia, 1997 ▶) and DIAMOND (Brandenburg, 1998 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808015286/at2569sup1.cif

e-64-o1158-sup1.cif^{(20.2KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808015286/at2569Isup2.hkl

e-64-o1158-Isup2.hkl^{(181.6KB, 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
C10—H10⋯Cg1ⁱ	0.95	2.57	3.485 (3)	163
C4—H4⋯O2	0.95	2.21	3.035 (2)	145
C15—H15⋯O3ⁱⁱ	0.95	2.42	3.303 (2)	155

Open in a new tab

Symmetry codes: (i) Inline graphic ; (ii) . Cg1 is the centroid of the C13–C18 benzene ring.

supplementary crystallographic information

Comment

This work is related to our communications on the synthesis and structures of 2-methyl-1-(phenylsulfonyl)naphtho[2,1-b]furan analogues, viz. 2-methyl-1-(phenylsulfonyl)naphtho[2,1-b]furan (Choi et al., 2008a) and 7-bromo-2-methyl-1-(phenylsulfonyl)naphtho[2,1-b]furan (Choi et al., 2008b). Here we report the crystal structure of the title compound, 7-bromo-2-methyl-1-tosylnaphtho[2,1-b]furan (Fig. 1).

The naphthofuran unit is essentially planar, with a mean deviation of 0.01 Å from the least-squares plane defined by the thirteen constituent atoms. The 4-tolyl ring (C13-C18) makes a dihedral angle of 70.96 (6)° with the plane of the naphthofuran fragment. The molecular packing (Fig. 2) is stabilized by two different π—π interactions within each stack of molecule; one between the central benzene ring (Cg3) and the furan ring (Cg4ⁱⁱ) of the adjacent naphthofuran fragments {distance; 3.672 (3) Å}, and a second between the brominated benzene ring (Cg2) and the central benzene ring (Cg3ⁱⁱⁱ) of the adjacent naphthofuran fragments {distance; 3.858 (3) Å} (Fig. 2; Cg2, Cg3 and Cg4 are the centroids of the C3-C8 benzene, the C2/C3/C8/C9/C10/C11 benzene, and the O1/C12/C1/C2/C11 furan rings, respectively, symmetry code as in Fig. 2). The crystal packing is further stabilized by C—H···π interaction between a central benzene H atom of naphthofuran unit and the 4-tolyl ring of the tosyl substituent, with a C10—H10···Cg1ⁱ separation of 2.57 Å (Fig. 2 and Table 1; Cg1 is the centroid of the C13-C18 phenyl ring; symmetry code as in Fig. 2). Additionally, inter- and intramolecular C—H···O interactions in the structure were observed (Fig. 2 and Table 1; symmetry code as in Fig. 2).

Experimental

3-Chloroperoxybenzoic acid (77%, 377 mg, 1.68 mmol) was added in small portions to a stirred solution of 7-bromo-2-methyl-1-(4-tolylsulfanyl)naphtho[2,1-b]furan (306 mg, 0.8 mmol) in dichloromethane (30 ml) at 273 K. After being stirred at room temperature for 4 h, the mixture was washed with saturated sodium bicarbonate solution and the organic layer was separated, dried over magnesium sulfate, filtered and concentrated in vacuum. The residue was purified by column chromatography (chloroform) to afford the title compound as a colourless solid [yield 79%, m.p. 480-481 K; R_f = 0.51 (chloroform)]. Single crystals suitable for X-ray diffraction were prepared by evaporation of a solution of the title compound in chloroform at room temperature. Spectroscopic analysis: ¹H NMR (CDCl₃, 400 MHz) δ 2.35 (s, 3H), 2.99 (s, 3H), 7.27 (s, 2H), 7.59-7.68 (m, 3H), 7.83 (d, J = 8.08 Hz, 2H), 8.03 (s, 1H), 8.91 (s, J = 9.16 Hz, 1H); EI-MS 416 [M+2], 414 [M⁺].