(RS)-1-[5-(2-Chloro­prop­yl)indolin-1-yl]ethanone

Xue-Mei Yang

doi:10.1107/S1600536810050476

. 2010 Dec 8;67(Pt 1):o51. doi: 10.1107/S1600536810050476

(RS)-1-[5-(2-Chloropropyl)indolin-1-yl]ethanone

Xue-Mei Yang ^a,^*

PMCID: PMC3050396 PMID: 21522761

Abstract

In the title compound, C₁₃H₁₆ClNO, the acetylindoline moiety is roughly planar (r.m.s. deviation = 0.0048 Å). The chloropropyl group is out of the plane and is statistically disordered over two positions. Indeed, the Cl and CH₃ groups located on the stereogenic carbon exchange with each other. The whole crystal is a racemate. Non-classical C—H⋯O hydrogen bonds between symmetry-related benzene rings stabilize the crystal structure.

Related literature

The title compound was synthesized as an intermediate in the search for a new synthetic route to silodosin, an adrenoceptor antagonist, see: Asselin et al. (2000 ▶); Bremner et al. (2000 ▶); Elworthy et al. (1997 ▶); Sorbera et al. (2001 ▶). For related structures, see: Moreno et al. (1998 ▶); Wang et al.(2007 ▶).

Experimental

Crystal data

C₁₃H₁₆ClNO
M _r = 237.72
Triclinic,
a = 6.9041 (5) Å
b = 8.4887 (6) Å
c = 10.6463 (7) Å
α = 76.423 (1)°
β = 86.955 (1)°
γ = 89.969 (1)°
V = 605.61 (7) Å³
Z = 2
Mo Kα radiation
μ = 0.29 mm⁻¹
T = 173 K
0.46 × 0.41 × 0.22 mm

Data collection

Bruker AXS SMART 1000 CCD diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 2008a ▶) T _min = 0.877, T _max = 0.938
4719 measured reflections
2343 independent reflections
1915 reflections with I > 2σ(I)
R _int = 0.016

Refinement

R[F ² > 2σ(F ²)] = 0.041
wR(F ²) = 0.113
S = 1.07
2343 reflections
163 parameters
5 restraints
H-atom parameters constrained
Δρ_max = 0.35 e Å⁻³
Δρ_min = −0.19 e Å⁻³

Data collection: SMART (Bruker, 2001 ▶); cell refinement: SAINT-Plus (Bruker, 2003 ▶); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXTL (Sheldrick, 2008b ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008b ▶); molecular graphics: ORTEPIII (Burnett & Johnson, 1996 ▶), ORTEP-3 for Windows (Farrugia, 1997 ▶) and PLATON (Spek, 2009 ▶); software used to prepare material for publication: SHELXTL.

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536810050476/dn2631sup1.cif

e-67-00o51-sup1.cif^{(18KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810050476/dn2631Isup2.hkl

e-67-00o51-Isup2.hkl^{(115.1KB, 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
C4—H4⋯O1ⁱ	0.95	2.45	3.388 (2)	168
C12—H12A⋯O1ⁱ	0.96	2.44	3.388 (2)	169

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Symmetry code: (i) Inline graphic .

Acknowledgments

We thank Mr Feng Xiaolong for his kind help.

supplementary crystallographic information

Comment

In searching for new synthetic route of silodosin, a adrenoceptor antagonist (Sorbera et al. 2001; Elworthy et al. 1997; Asselin et al. 2000; Bremner et al. 2000), we synthesized the title compound as racemic intermediate.

In the title compound, C₁₃H₁₆ClNO, the acetylindoline moiety is mainly planar with the largest deviation from the plane being 0.0076 (14)Å at C2. The chloropropane being out of the plane with the C12 atom located 1.0254 (0.0028)Å above the plane (Fig. 1). The chloropropane moiety is statistically disordered over two positions. Indeed, the Cl and CH₃ located on the stereogenic carbon exchange each other. The geometry within the 1-acetylindoline fragment compares well with related structures as 1-acetylindoline (Moreno et al., 1998) or 1-(trifluoro)acetylindoline (Wang et al., 2007).

Non-classical C—H···O hydrogen bonds (Table 1) link the molecules forming layers parallel to the (1 0 0) plane (Figure 2).

Experimental

1 g of (R/S)-1-(1-acetylindolin-5-yl)-2-chloropropan-1-one was dissolved in 50 ml of trifluroacetic acid, and then 1.067 g of triethylsilane was added dropwise within 20 min in -5¯C. The system was stirred overnight in ambient temperature, then extra trifluroacetic acid was distilled out in reduced pressure. To the resulting oil was added 20 ml of water and 5 ml of n-hexane, and stirred for 10 min. The white precipitate was collected through filtration, washed by n-hexane and dried to get 1.24 g of the targeting product. Crystals suitable for X-ray diffraction were obtained by slow evaporation of an ethyl acetate solution. Spectroscopic analysis: ¹H NMR (CDCl₃,δ, p.p.m.): 1.519–1.542(d,3H), 2.236(s,3H), 2.882–3.093(t,2H), 3.171–3.227(t,2H), 4.037–4.124(t,2H), 4.147–4.213(t, 1H), 7.009–7.0977(s,2H), 8.111–8.140(d,1H).