Carbamate → 1,1-Dimethylethyl (1-{[(1R)-4,9-dioxo-1,2-dihydro-4H,9H-imidazo[1,2,3-ij]-1,8-naphthyridin-1-yl]methyl}-4-piperidinyl)carbamate

Participants

Reaction Conditions

Reaction Steps

A solution of 1,1-dimethylethyl (1-{[(2R)-4,9-dioxo-1,2,8,9-tetrahydro-4H,7H-imidazo[1,2,3-ij]-1,8-naphthyridin-2-yl]methyl}-4-piperidinyl)carbamate (5.710 g, 14.19 mmol) in 1,4-dioxane (50 ml) at rt was treated with DDQ (4.83 g, 21.28 mmol) and then heated at 120° C. for 1 h. The reaction was then cooled to rt. The reaction mixture was treated with saturated aqueous K2CO3 (5%, 1000 ml) and extracted with DCM (3×500 ml). The combined organic solvents were then dried (MgSO4), filtered, evaporated to give the crude product as a brown solid. The reaction was repeated using a further portion of carbamate (2.889 g, 7.18 mmol) in 1,4-dioxane (50 ml) with DDQ (2.444 g, 10.77 mmol). The reaction was performed and worked up as above and the combined residues were chromatographed (0-100% EtOAc:40-60 Petroleum ether then 0-20% MeOH:EtOAc) to give the product as a brown solid (1.532 g, 18%).

Provenance & Evidence