3-(1-Adamant-yl)-6-methyl-3-(3-methyl-benz-yl)isochroman-1-one.

In the title compound, C(28)H(32)O(2), the oxanone ring adopts distorted half-boat conformation with the following Cremer and Pople puckering parameters: Q = 0.619 (2) Å, θ = 0.75 (19) and ϕ = 172 (13)°. The dihedral angle betwen two benzene rings is 21.32 (7)°. The adamantane unit consists of three fused cyclo-hexane rings in classical chair conformations, with absolute values of C-C-C-C torsion angles in the range 57.5 (2)-60.9 (2)°. Weak inter-actions of the type C-H⋯O link mol-ecules of each enanti-omer into chains parallel to the b axis and lying about inversion centers. The crystal packing is also stabilized by inter-molecular π-π stacking inter-actions [centroid-centroid distance of 3.8566 (11) Å].

In the title compound, C 28 H 32 O 2 , the oxanone ring adopts distorted half-boat conformation with the following Cremer and Pople puckering parameters: Q = 0.619 (2) Å , = 0.75 (19) and ' = 172 (13) . The dihedral angle betwen two benzene rings is 21.32 (7) . The adamantane unit consists of three fused cyclohexane rings in classical chair conformations, with absolute values of C-C-C-C torsion angles in the range 57.5 (2)-60.9 (2) . Weak interactions of the type C-HÁ Á ÁO link molecules of each enantiomer into chains parallel to the b axis and lying about inversion centers. The crystal packing is also stabilized by intermolecularstacking interactions [centroid-centroid distance of 3.8566 (11) Å ].
The financial support of this work by the Czech Ministry of Education (project No. MSM 7088352101) is gratefully acknowledged.

Comment
The title molecule is related to the isochromanone derivatives that are generally known as regulators of plant growth (Bianchi et al., 2004). In the dependence on their chemical structure and concentration they can act either as inhibitors or stimulators in these processes. Some substituted isochromanones isolated from myxobacteria strains were introduced as antifungal agents (Buntin et al., 2008).

Experimental
The title compound was prepared by the reaction of 3-methylbenzylmagnesium chloride with adamantane-1-carbonyl chloride in diethyl ether (Vícha et al., 2006). A solution of 3-methylbenzylmagnesium chloride (5 ml, 0.030 mol) in diethyl ether was added to a well stirred solution of adamantane-1-carbonyl chloride (0.8858 g, 0.004 mol) in 5 ml of dry diethyl ether at 273 K. The mixture was stirred for 72 h at room temperature and the reaction mixture was quenched with 15 ml of HCl (1 M).
After additional 15 min of vigorous stirring, the aqueous layer was separated and washed three times with 15 ml of diethyl ether. Combined organic layers were washed with K 2 CO 3 (1.16 M), dried over Na 2 SO 4 and evaporated in vacuum. Crude product was purified on column (silica gel; petroleum ether/ethyl acetate, v/v, 16/1). The title compound was obtained as a colorless crystalline powder (350 mg, 41%), melting point 447-448 K). Crystals suitable for X-ray analysis were acquired by spontaneous evaporation from deuterochloroform at 298 K.

Refinement
Hydrogen atoms were positioned geometrically and refined as riding using standard SHELXTL (Sheldrick, 2008) facilities, with their U iso set to either 1.2U eq or 1.5U eq (methyl) of their parent atoms.  Fig. 1. ORTEP (Farrugia, 1997) of the asymmetric unit with atoms represented as 50% probability ellipsoids and H atoms shown as small spheres at arbitrary radii.   (2)