4-(2-Chlorophenyl)-9-methoxy-4,5,6,10c-tetrahydropyrrolo[3,4-c]carbazole-1,3(2H,3aH)-dione → 4-(2-Chlorophenyl)-9-methoxypyrrolo[3,4-c]carbazole-1,3(2H,6H)-dione

Participants

Reaction Steps

Manganese dioxide (12.0 g) was added to a solution of 4-(2-Chlorophenyl)-9-methoxy-4,5,6,10c-tetrahydropyrrolo[3,4-c]carbazole-1,3(2H,3aH)-dione (IV; Ar=2-chlorophenyl, R10═H (32) prepared as described in example 68 (2.1 g, 5.51 mmol) in dioxane (100 mL) and the mixture was refluxed with stirring for 16 h. The mixture was filtered hot through a plug of Celite, washing through with more dioxane and then 10% methanol/dioxane. The combined filtrate and washings were concentrated to dryness and the residue was adsorbed onto silica and chromatographed. Elution with ethyl acetate/petroleum ether (3:7) gave 4-(2-Chlorophenyl)-9-methoxypyrrolo[3,4-c]carbazole-1,3(2H,6H)-dione (V; Ar=2-chlorophenyl, R10═H (33) in a yield of 1.66 g, 79% which crystallised from THF/petroleum ether as a yellow powder, mp 170–175° C. (dec). 1H NMR δ [(CD3)2SO 11.96 (br s, 1H), 11.08 (br s, 1H), 8.46 (d, J=2.6 Hz, 1H), 7.60–7.55 (m, 3H), 7.51–7.42 (m, 3H), 7.24 (dd, J=8.9, 2.6 Hz, 1H), 3.89 (s, 3H). Found: C, 65.64; H, 3.63; N, 7.12. C21H13ClN2O3.1/2H2O requires C, 65.37; H, 3.66; N, 7.26.

Provenance & Evidence