Ethyl chloroformate → carbonic acid 9-benzhydryloxy-7-[2-(4-fluoro-phenyl)-ethyl]-6,8-dioxo-7,8-dihydro-6H-pyrrolo[3,4-g]quinolin-5-yl ester ethyl ester

Participants

Reaction Conditions

Reaction Steps

7-[2-(4-Fluoro-phenyl)-ethyl]-5,9-dihydroxy-pyrrolo[3,4-g]quinoline-6,8-dione 310 (250 mg, 0.71 mmol).was dissolved in dioxane (3.6 ml) and H2O (2.4 ml) and cooled to 0° C. After 1.0 M NaOH (1.42 ml, 1.42 mmol) and ethylchloroformate (84.6 mg, 0.78 mmol) were added, the reaction was stirred at 0° C. for one hour. The reaction mixture was quenched with the addition of acetic acid (0.6 ml) and concentrated in vacuo. The crude mixture was diluted with ethyl acetate and washed once with 5% Citric Acid (aqueous), twice with water, once with brine, dried over magnesium sulfate, and concentrated in vacuo. The resulting residue was dissolved in 1,2-dichloroethane (4.0 ml) and to this was added diphenyl-methanediazonium 38 (252 mg, 1.3 mmol). The reaction mixture was then stirred overnight at room temperature. Following dilution with dichloromethane, the reaction mixture was washed with once with water, once with brine, dried over magnesium sulfate, and concentrated in vacuo. The residue was then purified by silica gel chromatography (1/1—hexane/ethyl acetate) to afford carbonic acid 9-benzhydryloxy-7-[2-(4-fluoro-phenyl)-ethyl]-6,8-dioxo-7,8-dihydro-6H-pyrrolo[3,4-g]quinolin-5-yl ester ethyl ester 311 (251 mg, 0.425 mmol, 65%). 1H NMR (d-DMSO) δ 9.19 (dd, 1H), 8.52 (dd, 1H), 7.90 (s, 1H), 7.80 (m, 1H), 7.54 (m, 4H), 7.20 (m, 8H), 7.02 (t, 2H), 4.24 (q, 2H), 3.79 (t, 2H), 2.90 (t, 2H), 1.25 (t, 3H). MS: 599.2 (M+23).

Provenance & Evidence