Structure of 6-dodecyl-2-methoxy-1,4-benzoquinone, a new synthetic contact allergen

C19H30O3, Mr = 306.45, triclinic, P-1, a = 5.453 (1), b = 5.608 (1), c = 30.129 (2) A, alpha = 85.85 (1), beta = 88.66 (1), gamma = 83.02 (1) degree, V = 912.0 (1) A3, Z = 2, Dx = 1.116 Mg m-3, Cu K alpha radiation, lambda = 1.5418 A, mu = 0.548 mm-1, F(000) = 336, T = 296 K, R is 0.040 for 2489 observed unique reflections. The aliphatic side chain is slightly rotated from the quinone ring. The angle between the quinone-ring plane and the mean dodecyl-chain plane is 20.8 (2) degrees. The average Csp3-Csp3 bond lengths and corresponding angles of the side chain are 1.515 (5) A and 113.8 (3) degrees. The average dimensions of the quinone ring are C-C 1.477 (4), C = C 1.337 (4), C = O 1.222 (3) A, C-C-C 118.9 (3), C = C-C 120.6 (3), O = C-C 120.6 (3)degrees. Neighbouring molecules form dimers by C-H...O interactions across centres of symmetry [C(3)...O(3) 3.413 (2) A]. The dimers are linked together via methyl H and carbonyl O along [100] [C(19)...O(3) 3.338 (3) A]; O(3) is a bifurcated acceptor.