1-tert-Butyl 2-ethyl 5-bromo-3-(thio­phen-2-ylcarbon­yl)-1H-indole-1,2-dicarboxyl­ate

Hassam, M.; Smith, V.J.

doi:10.1107/S1600536813000809

Volume 69
Part 2
Page o237
February 2013

Received 7 December 2012
Accepted 9 January 2013
Online 16 January 2013

Key indicators
Single-crystal X-ray study
T = 100 K
Mean (C-C) = 0.003 Å
Disorder in main residue
R = 0.029
wR = 0.066
Data-to-parameter ratio = 17.4
Details

1-tert-Butyl 2-ethyl 5-bromo-3-(thiophen-2-ylcarbonyl)-1H-indole-1,2-dicarboxylate

Mohammad Hassam ^a ^* and Vincent J. Smith ^a

^aDepartment of Chemistry and Polymer Science, University of Stellenbosch, Private Bag X1, Matieland 7602, South Africa
Correspondence e-mail: hassam@sun.ac.za

In the title compound, C₂₁H₂₀BrNO₅S, the thiophene group is located above the mean plane of the indole ring and displays rotational disorder (i.e. rotation through 180°). The site occupancy of the major component is 0.902 (2), while that of the minor component is 0.098 (2). In the crystal, pairs of weak C-HO interactions link the molecules into centrosymmetric dimers.

Related literature

For background to the use of indoles as scaffolds in the synthesis of HIV-agents, see: Hassam et al. (2012) and for a recent review on stages of non-nucleoside reverse transcriptase inhibitors, see: Reynolds et al. (2012). For the crystal structures of closely related compounds, see: Beddoes et al. (1986), Hassam & Smith (2012).

Experimental

Crystal data

C₂₁H₂₀BrNO₅S
M_r = 478.35
Monoclinic, C 2/c
a = 16.220 (3) Å
b = 15.361 (3) Å
c = 18.224 (4) Å
= 113.792 (2)°
V = 4154.7 (15) Å³
Z = 8
Mo K radiation
= 2.11 mm^-1
T = 100 K
0.34 × 0.21 × 0.17 mm

Data collection

Bruker APEXII CCD diffractometer
Absorption correction: multi-scan [symmetry-related measurements (SADABS; Bruker, 2009)] T_min = 0.537, T_max = 0.721
23562 measured reflections
4855 independent reflections
4101 reflections with I > 2(I)
R_int = 0.039

Refinement

R[F² > 2(F²)] = 0.029
wR(F²) = 0.066
S = 1.05
4855 reflections
279 parameters
13 restraints
H-atom parameters constrained
_max = 0.38 e Å^-3
_min = -0.38 e Å^-3

Table 1
Hydrogen-bond geometry (Å, °)

D-HA	D-H	HA	DA	D-HA
C12A-H12AO3ⁱ	0.95	2.48	3.418 (5)	169
Symmetry code: (i) $[-x, y, -z+{\script{1\over 2}}]$ .

Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT (Bruker, 2009); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: X-SEED (Barbour, 2001; Atwood & Barbour, 2003); software used to prepare material for publication: X-SEED.

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: JJ2160 ).

Acknowledgements

MH thanks Professor Willem A. L. van Otterlo and Dr S. C. Pelly for their valuable input and research oversight. Stellenbosch University's Science Faculty is also acknowledged for providing laboratory space and financial research support (Subcommittee B). The South African National Research Foundation (NRF), Pretoria, is also acknowledged for providing research funds.

References

Atwood, J. L. & Barbour, L. J. (2003). Cryst. Growth Des. 3, 3-8.
Barbour, L. J. (2001). J. Supramol. Chem. 1, 189-191.
Beddoes, R. L., Dalton, L., Joule, J. A., Mills, O. S., Street, J. D. & Watt, C. I. F. (1986). J. Chem. Soc. Perkin Trans. 2, pp. 787-797.
Bruker (2009). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.
Hassam, M., Basson, A. E., Liotta, D. C., Morris, L., van Otterlo, W. A. L. & Pelly, S. C. (2012). ACS Med. Chem. Lett. 3, 470-475.
Hassam, M. & Smith, V. J. (2012). Acta Cryst. E68, o3357.
Reynolds, C., Koning, C. B., Pelly, S. C., van Otterlo, W. A. L. & Bode, M. L. (2012). Chem. Soc. Rev. 41, 4657-4670.
Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.

organic compounds