CIF access Acta Cryst. (1999). C55, IUC9900073 [ doi:10.1107/S0108270199099230 ] 1,1-Bis(4-methoxyphenyl)-3,3-dimethylbutan-2-one S. S. Kuduva, A. K. Katz, H. L. Carrell and G. R. Desiraju Abstract The title compound, C 20 H 24 O 3 , was obtained as a by-product in the reaction of pinacolone and 4-iodoanisole. The crystal structure was determined at 120 (2) K. The molecule is bisected by a mirror plane (space group Pnma). Comment The title compound was obtained as a by-product in the reaction of pinacolone and 4-iodoanisole. Data were collected out to theta = 24.40 and it is observed that this is slightly less than recommended in Notes to Authors. Experimental Pinacolone and 4-iodoanisole were reacted in the presence of potassium tert-butoxide in dimethyl sulfoxide solution and stirred for 3 h in the dark at room temperature. Refinement Higher angle data were of insignificant intensity. Computing details Data collection: MADNES (Pflugrath & Messerschmidt, 1989); cell refinement: MADNES; data reduction: MADNES and Kabsch (1988); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997a); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997b). (IUC9900073) Crystal data C 20 H 24 O 3 V = 1681.0 (5) Å 3 M r = 312.39 Z = 4 Orthorhombic, Pnma Mo Kα a = 15.423 (2) Å µ = 0.08 mm −1 b = 18.571 (4) Å T = 120 (2) K c = 5.8691 (8) Å 0.30 × 0.10 × 0.04 mm