Phosphorus oxide (P4O10) → 3,3-dimethyl-6-methylthio-2,4(1H,3H)-quinolinedione

Participants

Reaction Conditions

Reaction Steps

Phosphorus pentoxide (4.49 g, 0.032 mol) was added to a stirred solution of N-(4-methylthiophenyl)-2,2-dimethylmalonamic acid (5.0 g, 0.020 mol) in methanesulfonic acid (35 ml). The reaction mixture was warmed to 70° C. and stirred for 90 mins. The product mixture was then cooled to room temperature and poured over ice. The product was extracted with ethyl acetate (2×200 ml). The organic extracts were combined, washed with water (200 ml), saturated sodium hydrogen carbonate solution (200 ml), dried (MgSO4) and concentrated in vacuo to give 3,3-dimethyl-6-methylthio-2,4(1H,3H)-quinolinedione as a yellow solid. Mp 152° C.

Provenance & Evidence