Maleimide → 6-(3-Hydroxypropyl)-9-methoxy-4-phenylpyrrolo[3,4-c]carbazole-1,3(2H,6H)-dione

Participants

Reaction Steps

5-Methoxy-2-[(E,Z)-2-phenylethenyl]-1H-indole (II; Ar=phenyl) (6.85 g, 27.5 mmol) was reacted with with 3-bromopropyl tert-butyl(dimethyl)silyl ether using the procedure described in example 38. The product isolated was reacted directly with maleimide (5.2 g) using the procedure described in example 68. Aromatisation of the crude Diels-Alder adduct using the procedure described in example 79 gave crude material that was then dissolved in methanol (300 mL) to which 1N hydrochloric acid (50 mL) was added. This solution was stirred at rt for 3h before being diluted with water and extracted with ethyl acetate. The organic layer was dried, the drying agent was removed and the solution was concentrated to dryness. The residue was adsorbed onto silica and chromatographed eluting with dichloromethane to ethyl acetate/dichloromethane (7:3). Trituration with diethyl ether gave alcohol (202) as a yellow powder (2.55 g, 23%), mp 241–243° C. 1H NMR δ [(CD3)2SO] 11.10 (br s, 1H), 8.56 (d, J=2.6 Hz, 1H), 7.82 (s, 1H), 7.67 (m, 3H), 7.47 (m, 3H), 7.30 (dd. J=9.0, 2.6 Hz, 1H), 4.66 (t, J=4.9 Hz, 1H), 4.55 (t, J=6.9 Hz, 2H), 3.90 (s, 3H), 3.39 (m. 2H), 1.93 (m, 2H). Found: C, 71.95; H, 5.09; N, 6.93. C24H20N2O4 requires: C, 71.99; H. 5.03; N. 6.99.

Provenance & Evidence