(±)-trans-3-Oxo-1,2,3,4,4a,9,10,10a-octa­hydro­phenanthrene-10a-carboxylic acid: catemeric hydrogen bonding in a δ-keto acid

Mark Davison; Roger A Lalancette; Hugh W Thompson; Alan J Miller

doi:10.1107/S1600536808026639

. 2008 Aug 23;64(Pt 9):o1813. doi: 10.1107/S1600536808026639

(±)-trans-3-Oxo-1,2,3,4,4a,9,10,10a-octahydrophenanthrene-10a-carboxylic acid: catemeric hydrogen bonding in a δ-keto acid

Mark Davison ^a, Roger A Lalancette ^a,^*, Hugh W Thompson ^a, Alan J Miller ^a

PMCID: PMC2960539 PMID: 21201790

Abstract

The title compound, C₁₅H₁₆O₃, aggregates as hydrogen-bonded catemers progressing from each carboxyl to the ketone of a screw-related neighbor [O⋯O = 2.6675 (14) Å and O—H⋯O = 170°]. Two parallel centrosymmetrically related single-strand hydrogen-bonding helices proceed through the cell in the b-axis direction. The packing includes three intermolecular C—H⋯O=C close contacts, involving both the ketone and the carboxyl group. The structure is isomorphous with that of the previously described Δ⁴ α,β-unsaturated ketone.

Related literature

For related literature, see: Allen et al. (1999 ▶); Borthwick (1980 ▶); Gavezzotti & Filippini (1994 ▶); Leiserowitz (1976 ▶); Miller et al. (1999 ▶); Steiner (1997 ▶); Thompson & McPherson (1977 ▶); Thompson & Shah (1983 ▶).

Experimental

Crystal data

C₁₅H₁₆O₃
M _r = 244.28
Monoclinic,
a = 9.7172 (4) Å
b = 12.2735 (6) Å
c = 10.4867 (5) Å
β = 102.6764 (19)°
V = 1220.20 (10) Å³
Z = 4
Cu Kα radiation
μ = 0.74 mm⁻¹
T = 100 (2) K
0.41 × 0.38 × 0.36 mm

Data collection

Bruker SMART CCD APEXII area-detector diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 2001 ▶) T _min = 0.750, T _max = 0.775
7219 measured reflections
2106 independent reflections
2019 reflections with I > 2σ(I)
R _int = 0.019

Refinement

R[F ² > 2σ(F ²)] = 0.039
wR(F ²) = 0.108
S = 1.05
2106 reflections
165 parameters
H-atom parameters constrained
Δρ_max = 0.25 e Å⁻³
Δρ_min = −0.20 e Å⁻³

Data collection: APEX2 (Bruker, 2006 ▶); cell refinement: APEX2; data reduction: SAINT (Bruker, 2005 ▶); program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536808026639/fl2217sup1.cif

e-64-o1813-sup1.cif^{(18.7KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808026639/fl2217Isup2.hkl

e-64-o1813-Isup2.hkl^{(103.6KB, 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
O3—H3⋯O1ⁱ	0.84	1.84	2.6675 (14)	170
C2—H2A⋯O2ⁱⁱ	0.99	2.45	3.3817 (16)	156
C4—H4B⋯O2ⁱⁱⁱ	0.99	2.60	3.5273 (18)	156
C8—H8A⋯O1^iv	0.95	2.55	3.2625 (17)	132

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

Acknowledgments

HWT is grateful to Professor Gree Loober Spoog for helpful consultations. The authors acknowledge support by NSF-CRIF grant No. 0443538.

supplementary crystallographic information

Comment

In ketocarboxylic acids the bias toward centrosymmetric acid pairing (Leiserowitz, 1976; Gavezzotti & Filippini, 1994; Allen et al., 1999) may be suppressed when molecular inflexibility diminishes the repertoire of conformational options. Keto acids with few fully rotatable bonds thus display an increased tendency to form acid-to-ketone H-bonding chains. In this context, we describe the title compound (I), which aggregates in the less common catemer mode.

Fig. 1 shows the asymmetric unit for (I) with its numbering. The sole option for full bond rotation involves the carboxyl group, which is turned so that its carbonyl lies over the ring system, with a C4A—C10A—C11—O2 torsion angle of 39.16 (17)°. Within the asymmetric unit, the dihedral angle for ketone (C2—C3—C4—O1) versus carboxyl (C10A—C11—O2—O3) is 86.06 (6)°. Because (I) is not dimeric, averaging of C—O bond lengths and C—C—O angles by disorder is precluded, and these values [1.2121 (17) & 1.3232 (17) Å] resemble ones typical for highly ordered carboxyls (Borthwick, 1980).

Fig. 2 illustrates the packing. The carboxyl-to-ketone H bonds proceed among molecules screw-related in b, generating two parallel single-strand helical catemers for each cell. These chains are centrosymmetrically related and thus counter-directional. For the ketone and carboxyl groups involved in each intermolecular H bond (Table 1), the C2—C3—C4—O1 versus C10A'-C11'-O2'-O3' [symmetry = 0.5 - x,-1/2 + y,0.5 - z] dihedral angle is 69.01 (6)°.

We characterize the geometry of H bonding to carbonyls using a combination of the H···O=C angle and the H···O=C—C torsion angle. These describe the approach of the H atom to the O in terms of its deviation from, respectively, C=O axiality and planarity with the carbonyl. In (I) these angles are 117° for H···O=C and -6.5° for H···O=C—C, extremely close to the "ideal" angles of 120 and 0°.

Within the 2.6 Å range we survey (Steiner, 1997), three intermolecular C—H···O=C close contacts were found in the packing, involving both the ketone and the carboxyl group. (Table 1).

Compound (I) is derived from the Δ⁴ isoskeletal unsaturated keto acid whose structure we have previously reported (Miller et al., 1999), and the molecular shapes of these two compounds are so similar that (I) was found to be isomorphous with the prior material.

Experimental

1-Tetralone was carbomethoxylated and then subjected to Robinson annulation as described by Thompson & McPherson (1977). The resulting unsaturated keto ester was hydrogenated over a Pd/C catalyst, after which Jones oxidation was employed to correct for overreduction. Mild saponification, modeled on that described by Thompson & Shah (1983), provided (I), which was sublimed and crystallized from diethyl ether to give the crystal used, m.p. 460 K. The solid-state (KBr) infrared spectrum of (I) has C=O absorptions at 1716 & 1685 cm^-1. This peak separation is typical of the H-bonding shifts in catemers, due to, respectively, its removal from the acid C=O and its addition to the ketone. In CHCl₃ solution, where dimers predominate, these peaks coalesce to a single absorption at 1707 cm^-1.