Methyl 3,4-dihydro-1-oxo-2(1H)-naphthylidenehydroxyacetate

C13H12O4, Mr = 232.2, monoclinic, P2(1)/c, a = 8.499 (2), b = 13.798 (4), c = 9.652 (2) A, beta = 98.25 (2) degrees, V = 1120.1 (9) A3, Z = 4, Dx = 1.377 g cm-3, lambda(Cu K alpha) = 1.54184 A, mu = 8.12 cm-1, F(000) = 488, T = 295 K, R = 0.042 for 1916 observations (of 2296 unique data). The molecule contains an enol subunit, the hydroxy group of which forms an intramolecular hydrogen bond to the cyclic carbonyl group, with an O...O distance of 2.4782 (14) A and an O-H...O angle of 143 (3) degrees. The refined position of the hydrogen atom is 1.16 (4) A from the hydroxy oxygen and 1.44 (4) A from the carbonyl oxygen, and the isotropic thermal parameter is large; B = 13 (1) A2. The enol C = C bond distance is 1.371 (1) A and its C-OH distance is 1.312 (1) A.