Triphenyl phosphite → Methyl 6-oxo-5,6-dihydropyrido[3,2-e]pyrrolo[1,2-a]pyrazine-3-carboxylate

Participants

Reaction Steps

Methyl 6-(2-(methoxycarbonyl)-1H-pyrrol-1-yl)-5-nitronicotinate (5.00 g, 16.38 mmol) was dissolved in dichloromethane (Volume: 82 ml) and to this solution was added triphenyl phosphite (0.051 g, 0.164 mmol), ammonium metavanadate (0.115 g, 0.983 mmol) and Pt/C (5% wt.) (0.639 g, 0.164 mmol). The reaction mixture was hydrogenated at 100 psi at 25° C. for 36 h. The reaction mixture was filtered through a short plug of celite and the plug and precipitate were washed well with methanol (100 mL) and then MeOH:DCM (100 mL, 1:1). The solids (celite and Pt/—C) were continuously extracted with MeOH/DCM mixture (1:1) in a Soxlet extractor for 2d. The extracts were combined with the earlier filtrates, concentrated in vacuo, crystallized with MeOH (100 mL) and the resulting solid was filtered off and suspended in ethyl ether (200 mL). The solid were filtered off and dried in vacuum to afford methyl 6-oxo-5,6-dihydropyrido[3,2-e]pyrrolo[1,2-a]pyrazine-3-carboxylate (2.15 g, 8.84 mmol, 54.0% yield) as a grey solid. 1H NMR (DMSO-d6) δ 11.49 (s, 1H), 8.69 (s, 1H), 8.15 (br. s., 1H), 8.11 (s, 1H), 7.16 (d, J=2.5 Hz, 1H), 6.78 (t, J=3.0 Hz, 1H), 3.91 (s, 3H). [M+H] calc'd for C12H9N3O3, 244; found, 244.

Provenance & Evidence