Ammonium [(1S)-(endo,anti)]-(−)-3-bromo­camphor-8-sulfonate

Muhammad Athar Abbasi; Aziz-ur-Rehman; Mehmet Akkurt; Muhammad Jahangir; Seik Weng Ng; Islam Ullah Khan

doi:10.1107/S1600536810022804

. 2010 Jun 18;66(Pt 7):o1707–o1708. doi: 10.1107/S1600536810022804

Ammonium [(1S)-(endo,anti)]-(−)-3-bromocamphor-8-sulfonate

Muhammad Athar Abbasi ^a,^‡, Aziz-ur-Rehman ^a, Mehmet Akkurt ^b,^*, Muhammad Jahangir ^a, Seik Weng Ng ^c, Islam Ullah Khan ^a

PMCID: PMC3006721 PMID: 21587927

Abstract

In the title molecular salt, NH₄ ⁺·C₁₀H₁₄BrO₄S⁻, the norbornane skeleton of the anion is composed of two five-membered rings in envelope conformations and a six-membered ring with one Br atom, one carbonyl O atom and a methyl group held in a boat conformation by a bridging methylene group. Short intramolecular C—H⋯O and C—H⋯Br interactions occur. In the crystal, the component ions are linked by intermolecular N—H⋯O and C—H⋯O hydrogen bonds.

Related literature

For further synthetic details, see: Smith et al. (2008 ▶). For other structures with the norbornane skeleton, see: Jauch et al. (1992 ▶); Ustabaş et al. (2006 ▶); Ersanlı et al. (2005 ▶). For the use of 3-bromocamphor-8-sulfonic acid and its ammonium salts as chiral auxillaries for the optical resolution of enantiomeric amines through diasteriomeric salt formation, see: Bálint et al. (1999 ▶); Pellati et al. (2010 ▶); Roy et al. (2009 ▶); Zhao et al. (2002 ▶). For puckering parameters, see: Cremer & Pople (1975 ▶).

Experimental

Crystal data

NH₄ ⁺·C₁₀H₁₄BrO₄S⁻
M _r = 328.22
Monoclinic,
a = 7.2449 (2) Å
b = 7.0049 (1) Å
c = 13.2428 (3) Å
β = 104.704 (1)°
V = 650.06 (3) Å³
Z = 2
Mo Kα radiation
μ = 3.33 mm⁻¹
T = 296 K
0.42 × 0.14 × 0.11 mm

Data collection

Bruker Kappa APEXII CCD diffractometer
Absorption correction: refined from ΔF (XABS2; Parkin et al., 1995 ▶) T _min = 0.336, T _max = 0.711
2775 measured reflections
2775 independent reflections
2586 reflections with I > 2σ(I)

Refinement

R[F ² > 2σ(F ²)] = 0.027
wR(F ²) = 0.065
S = 1.03
2775 reflections
168 parameters
5 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.35 e Å⁻³
Δρ_min = −0.47 e Å⁻³
Absolute structure: Flack (1983 ▶), 1155 Freidel pairs
Flack parameter: −0.021 (7)

Data collection: APEX2 (Bruker, 2007 ▶); cell refinement: SAINT (Bruker, 2007 ▶); 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 ▶); software used to prepare material for publication: WinGX (Farrugia, 1999 ▶), PARST (Nardelli, 1983 ▶) and PLATON (Spek, 2009 ▶).

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536810022804/hb5484sup1.cif

e-66-o1707-sup1.cif^{(19.4KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810022804/hb5484Isup2.hkl

e-66-o1707-Isup2.hkl^{(136.2KB, 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
N1—H1N⋯O1ⁱ	0.92 (3)	1.92 (3)	2.835 (4)	173 (3)
N1—H2N⋯O2ⁱⁱ	0.90 (3)	2.05 (3)	2.899 (3)	157 (3)
N1—H3N⋯O2	0.92 (3)	1.97 (3)	2.887 (3)	176 (3)
N1—H4N⋯O3ⁱⁱⁱ	0.92 (3)	1.93 (3)	2.827 (3)	167 (4)
C4—H4B⋯Br1	0.97	2.71	3.221 (3)	113
C8—H8A⋯O2	0.96	2.44	3.104 (3)	126
C10—H10⋯O1ⁱ	0.98	2.49	3.451 (4)	167

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

Acknowledgments

The authors are grateful to the Higher Education Commission for financial support to purchase the diffractometer.

supplementary crystallographic information

Comment

3-Bromocamphor-8-sulfonic acid and its ammonium salts have extensively been used as chiral auxillaries for the optical resolution of a number of enantiomeric amines through diasteriomeric salt formation (Bálint et al., 1999; Zhao et al., 2002; Roy et al., 2009; Pellati et al., 2010).

In the bicyclo[2.2.1]heptane (norbornane) skeleton of the title compound, (I), (Fig. 1), the two five-membered rings have envelope conformations, with atom C2 displaced by 0.365 (3) Å from the C2–C6 plane [the puckering parameters (Cremer & Pople, 1975) are Q₂ = 0.573 (3) Å and φ₂ = 5.3 (3)°] and by 0.397 (3) Å from the C2/C3/C6/C9/C10 plane [the puckering parameters: Q₂ = 0.615 (3) Å and φ₂ = 181.6 (3)°] and the six-membered ring (C3–C6/C9/C10) adopts a boat conformation by the puckering parameters Q_T = 0.970 (3) Å, θ = 92.03 (18)° and φ = 357.34 (19) °.

In (I), the C—C single-bond lengths range from 1.491 (5) to 1.575 (4) Å, with a mean value of 1.535 (4) Å. In the bicyclo[2.2.1]heptane fragment, the angles between planes A (C3/C2/C6), B (C3–C6) and C (C3/C6/C9/C10) are as follows: A/B= 53.65 (19)°, A/C= 58.14 (18)° and B/C= 68.22 (13)°.

In the crystal, adjacent molecules of (I) are linked by intermolecular N—H···O and C—H···O hydrogen bonds (Table 1, Fig. 2).

Experimental

3-Bromocamphor-8-sulfonic acid ammonium salt was prepared by modification in the reported method (Smith et al., 2008). 3-Bromocamphor-8-sulfonic acid (1 g) was dissolved in 15 ml of ethanol and then 6 ml of NH₃ solution were added. The mixture was stirred until a clear solution was observed (about 20 min). The solution was slowly concentrated on water bath to half the volume over a 2 h period. The concentrate was allowed to crystallize undisturbed for 48 h. The resulting colourless prisms of (I) were carefully separated by filteration and washed with three 0.5-ml portions of petroleum ether.