6-Methoxycarbonylmethoxy-5-nitro-nicotinic acid ethyl ester → 2-Oxo-2,3-dihydro-1H-pyrido[2,3-b][1,4]oxazine-7-carboxylic acid ethyl ester

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Reaction Conditions

Reaction Steps

To a solution of 6-methoxycarbonylmethoxy-5-nitro-nicotinic acid ethyl ester (3.271 g) in acetic acid (25 ml) was added iron powder (9.64 g). The mixture was stirred for 2 h at 60° C. The mixture was filtered and the filter cake was washed with acetic acid, EtOAc, EtOH, dichloromethane and with MeOH. The filtrate was concentrated. The residue was suspended in CH2Cl2/MeOH 9:1 and passed with more of the same solvent mixture over silica gel to give the title compound (1.52 g) as a light brown solid. MS (m/e)=223.1 [M+H+].

Provenance & Evidence