2-(1-Adamantyl)-4-bromoanisole at 123 K

In the title compound [systematic name: 2-(1-adamantyl)-4-bromo-1-methoxybenzene], C17H21BrO, two weak intramolecular C—H⋯O hydrogen bonds influence the molecular conformation. The crystal packing exhibits C—H⋯π interactions, with a relatively short intermolecular C⋯Cg contact of 3.568 (5) Å, where Cg is the centroid of the benzene ring. The crystal studied exhibited inversion twinning.

systems and the design of organic crystals, it is of interest to study the effects of some simple functional substituents having hydrogen-bonding ability on the symmetry of the crystals of adamantane derivatives. The title compound is an important intermediate of adapalene, which is a new synthetic retinoid of the naphthoic acid series, and was developed for the topical treatment of Acne vulgaris and prevention of some forms of cancer, including the acute promyelocytic leukaemia (Chomienne et al., 1994). Here we report the crystal structure of the title compound ( Fig. 1).
In the title compound, the structural parameters of the adamantyl are closely comparable to those found in reported molecule (Pouwer et al., 2007). The C atoms of the adamantine moiety have Csp 3 hybridized orbitals, with C-C-C angles in the range 106.6 (4)-111.6 (4)°. The methoxy group and bromo group are coplanar with the benzene ring.
It is of note that the O atoms of the methoxy group participates in formation of two intramolecular C-H···O interactions,and both intramolecular C-H···O interactions are nearly the same (Table.1). Meanwhile, in the crystal structure, an intermolecular C-H···π interaction involving the benzene ring (with the centroid Cg) is observed (Table 1).

Experimental
The title compound was prepared according to the literature method (Antibes et al., 1988). Crystals suitable for X-ray analysis were obtained by slow evaporation of an 2-propanol solution at 295 K.

Special details
Geometry. All e.s. Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating Rfactors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.