Methyl 3,5,5,6,8,8-hexa­methyl-5,6,7,8-tetra­hydro­naphthalene-2-carboxyl­ate (AHTN–COOMe)

Kuhlich, P.; Emmerling, F.; Piechotta, C.; Nehls, I.

doi:10.1107/S1600536811002601

Volume 67
Part 2
Page o485
February 2011

Received 17 January 2011
Accepted 19 January 2011
Online 26 January 2011

Key indicators
Single-crystal X-ray study
T = 193 K
Mean (C-C) = 0.002 Å
Disorder in main residue
R = 0.054
wR = 0.152
Data-to-parameter ratio = 14.2
Details

Methyl 3,5,5,6,8,8-hexamethyl-5,6,7,8-tetrahydronaphthalene-2-carboxylate (AHTN-COOMe)

Paul Kuhlich,^a Franziska Emmerling,^a ^* Christian Piechotta ^a and Irene Nehls ^a

^aBAM Federal Institute for Materials Research and Testing, Richard-Willstätter-Strasse 11, D-12489 Berlin-Adlershof, Germany
Correspondence e-mail: franziska.emmerling@bam.de

Crystals of the title compound, C₁₈H₂₆O₂, were grown from ethyl acetate. Due to the racemic precursor, the title compound is also obtained as a racemate. Disorder was observed during structure refinement, originating from two possible half-chair conformations of the non-aromatic ring. The disorder was refined by introducing split positions in the cyclo-hexane ring regarding the two possible R and S-enantiomers at the chiral CH group [ratio 0.744 (3):0.256 (3)]. The crystal structure features pairs of inversion-related molecules connected by pairs of non-classical C-HO hydrogen bonds.

Related literature

For the occurrence of the title compound in human breast milk and the fatty tissue of fish, see: Valdersnes et al. (2006). The title compound is the product of an esterification of 3,5,5,6,8,8-hexamethyl-5,6,7,8-tetrahydronaphthalene-2-carboxylic acid (AHTN-COOH) with methanol. For the synthesis of the acid, see: Kuhlich et al. (2010); Valdersnes et al. (2006). For the crystal structures of AHTN and AHTN-COOH, see: De Ridder et al. (1990) and Kuhlich et al. (2010), respectively. For the environmental occurrence and estrogenic activity of AHTN, see: Heberer (2003); Bitsch et al. (2002). For puckering parameters, see: Cremer & Pople (1975).

Experimental

Crystal data

C₁₈H₂₆O₂
M_r = 274.39
Monoclinic, P 2₁ /n
a = 11.5049 (11) Å
b = 11.9482 (5) Å
c = 12.1078 (13) Å
= 102.612 (5)°
V = 1624.2 (2) Å³
Z = 4
Cu K radiation
= 0.55 mm^-1
T = 193 K
0.45 × 0.40 × 0.30 mm

Data collection

Enraf-Nonius CAD-4 diffractometer
5083 measured reflections
3062 independent reflections
2856 reflections with I > 2(I)
R_int = 0.047
3 standard reflections every 60 min intensity decay: 3%

Refinement

R[F² > 2(F²)] = 0.054
wR(F²) = 0.152
S = 1.03
3062 reflections
216 parameters
10 restraints
H-atom parameters constrained
_max = 0.29 e Å^-3
_min = -0.26 e Å^-3

Table 1
Hydrogen-bond geometry (Å, °)

D-HA	D-H	HA	DA	D-HA
C18-H26O2ⁱ	0.98	2.47	3.397 (2)	157
Symmetry code: (i) -x+1, -y+3, -z.

Data collection: CAD-4 Software (Enraf-Nonius, 1989); cell refinement: CAD-4 Software; data reduction: CORINC (Dräger & Gattow, 1971); program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: PLATON (Spek, 2009); software used to prepare material for publication: PLATON.

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: ZL2346 ).

Acknowledgements

The authors want to thank Dr Dietmar Pfeifer (BAM, Berlin) for a helpful discussion regarding the interpretation of the NMR data.

References

Altomare, A., Burla, M. C., Camalli, M., Cascarano, G. L., Giacovazzo, C., Guagliardi, A., Moliterni, A. G. G., Polidori, G. & Spagna, R. (1999). J. Appl. Cryst. 32, 115-119.
Bitsch, N., Dudas, C., Korner, W., Failing, K., Biselli, S., Rimkus, G. & Brunn, H. (2002). Arch. Environ. Contam. Toxicol. 43, 257-264.
Cremer, D. & Pople, J. A. (1975). J. Am. Chem. Soc. 97, 1354-1358.
De Ridder, D. J. A., Goubitz, K. & Schenk, H. (1990). Acta Cryst. C46, 2200-2202.
Dräger, M. & Gattow, G. (1971). Acta Chem. Scand. 25, 761-762.
Enraf-Nonius (1989). CAD-4 Software. Enraf-Nonius, Delft, The Netherlands.
Heberer, T. (2003). Acta Hydrochim. Hydrobiol. 30, 227-243.
Kuhlich, P., Göstl, R., Metzinger, R., Piechotta, C. & Nehls, I. (2010). Acta Cryst. E66, o2687.
Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.
Spek, A. L. (2009). Acta Cryst. D65, 148-155.
Valdersnes, S., Kallenborn, R. & Sydnes, L. K. (2006). Int. J. Environ. Anal. Chem. 86, 461-471.

organic compounds