7,8,9,10-Tetrahydro-8-methyl-2,3-bis(phenylmethoxy)-pyrido[4,3-f]quinoxalin-6-yl phosphonic acid diethyl ester → 1,2,3,4,7,8,9,10-Octahydro-8-methyl-2,3-dioxopyrido[4,3-f]quinoxalin-6-yl phoshonic acid diethyl ester

Participants

Reaction Steps

A solution of the compound from Example 105 (0.34 g, 0.65 mmol) was dissolved in 60 mL of acetic acid and hydrogenated at 52 psi over 20% Pd/C. The reaction mixture was filtered and concentrated. The residue was dissolved in EtOH (3 mL) and concentrated. This procedure was repeated several times. The residue was then dissolved in EtOH and triturated with ethyl acetate. The solid which formed was collected by suction filtration and dried under vacuum to give the title compound as a yellow solid (0.20 g, 83% yield) mp 310-330° C. (dec).

Provenance & Evidence