3-(4-Fluoro­benz­yl)-1H-isochromene-1-thione

Tariq Mahmood Babar; Ghulam Qadeer; Nasim Hasan Rama; Muhammad Khawar Rauf; Wai-Yeung Wong

doi:10.1107/S1600536809004152

. 2009 Feb 11;65(Pt 3):o500. doi: 10.1107/S1600536809004152

3-(4-Fluorobenzyl)-1H-isochromene-1-thione

Tariq Mahmood Babar ^a, Ghulam Qadeer ^a,^*, Nasim Hasan Rama ^a,^‡, Muhammad Khawar Rauf ^a, Wai-Yeung Wong ^b,^§

PMCID: PMC2968631 PMID: 21582165

Abstract

In the molecule of the title compound, C₁₆H₁₁FOS, the benzene ring is oriented at a dihedral angle of 89.68 (3)° with respect to the planar [maximum deviation 0.009 (2) Å] isocoumarin ring system. An intramolecular C—H⋯S interaction results in the formation of a planar five-membered ring. In the crystal structure, intermolecular C—H⋯O hydrogen bonds link the molecules into chains parallel to the c axis. A π–π contact between the isocoumarin rings [centroid–centroid distance = 3.818 (3) Å] may further stabilize the structure.

Related literature

For general background, see: Barry (1964 ▶); Sturtz et al. (2002 ▶); Rossi et al. (2003 ▶); Powers et al. (2002 ▶); Thomas & Jens (1999 ▶). For a related structure, see: Abid et al. (2006 ▶). For bond-length data, see: Allen et al. (1987 ▶).

Experimental

Crystal data

C₁₆H₁₁FOS
M _r = 270.31
Monoclinic,
a = 8.7346 (6) Å
b = 17.9516 (11) Å
c = 8.4481 (5) Å
β = 95.026 (1)°
V = 1319.57 (14) Å³
Z = 4
Mo Kα radiation
μ = 0.25 mm⁻¹
T = 294 (2) K
0.30 × 0.25 × 0.20 mm

Data collection

Bruker SMART CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2001 ▶) T _min = 0.805, T _max = 0.952
7856 measured reflections
3188 independent reflections
2655 reflections with I > 2σ(I)
R _int = 0.016

Refinement

R[F ² > 2σ(F ²)] = 0.046
wR(F ²) = 0.150
S = 1.03
3188 reflections
172 parameters
H-atom parameters constrained
Δρ_max = 0.34 e Å⁻³
Δρ_min = −0.30 e Å⁻³

Data collection: SMART (Bruker, 2001 ▶); cell refinement: SAINT (Bruker, 2002 ▶); 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: SHELXTL (Sheldrick, 2008 ▶) and PLATON.

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809004152/hk2617sup1.cif

e-65-0o500-sup1.cif^{(16.1KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809004152/hk2617Isup2.hkl

e-65-0o500-Isup2.hkl^{(156.4KB, 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
C1—H1A⋯S1	0.93	2.78	3.142 (2)	105
C3—H3A⋯O1ⁱ	0.93	2.60	3.529 (2)	178

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Symmetry code: (i) Inline graphic .

Acknowledgments

The authors gratefully acknowledge the financial support of the Higher Education Commission, Islamabad, Pakistan.

supplementary crystallographic information

Comment

The isocoumarin nucleus is an abundant structural motif in natural products (Barry, 1964). Many constituents of the steadily growing class of known isocoumarins exhibit valuable biological properties such as antifungal (Sturtz et al., 2002), antitumor or cytotoxic, anti-inflammatory, anti-allergic (Rossi et al., 2003) and enzyme inhibitory (Powers et al., 2002) activities. Naturally occurring halo-isocoumarins and their halogeno-3,4-dihydroiscoumarin derivatives are very rare. However, a few examples of naturally occurring chlorine containing isocoumarins are known (Thomas & Jens, 1999). In view of the importance of this class of compounds, the title compound, an isocoumarine derivative containing 4-fluorobenzyl substituent has been synthesized, and we report herein its crystal structure.

In the molecule of the title compound (Fig. 1), the bond lengths (Allen et al., 1987) and angles are within normal ranges, and comparable with the corresponding values in 3-(2-chlorobenzyl)isocoumarin (Abid et al., 2006). Rings A (C1-C6), B (O1/C5-C9) and C (C11-C16) are, of course, planar and the dihedral angles between them are A/B = 0.29 (3)°, A/C = 89.77 (4)° and B/C = 89.53 (3)°. The intramolecular C-H···S interaction (Table 1) results in the formation of a planar five-membered ring D (S1/C1/C6/C7/H1A).

In the crystal structure, intermolecular C-H···O hydrogen bonds (Table 1) link the molecules into chains parallel to the c-axis (Fig. 2), in which they may be effective in the stabilization of the structure. The π-π contact between the isocoumarine rings, Cg1—Cg2ⁱ [symmetry code: (i) -x, -y, 1 - z, where Cg1 and Cg2 are centroids of the rings A (C1-C6) and B (O1/C5-C9), respectively] may further stabilize the structure, with centroid-centroid distance of 3.818 (3) Å.

Experimental

As shown in Scheme 2, the title compound was synthesized by refluxing 3-(4-fluorobenzyl)-1H-isochromen-1-one (0.5 g, 1.8 mmol) with Lawesson's reagent (0.89 g, 2.2 mmol) in dry toluene for 4 h. Pure thioisocoumarin was obtained by recrystalization in methanol (yield; 90%, m.p. 665-667 K).