Sodium Hydroxide → 2,6-Diethyl-1,4-dihydro-4-oxopyridine-3-carboxylic acid

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Reaction Steps

2M Sodium hydroxide (30 ml) was added to a solution of methyl 2,6-diethyl-1,4-dihydro-4-oxopyridine-3-carboxylate (obtained as described in European Patent Application No. 453210) in methanol (60 ml) and the solution was heated under reflux for 48 hours. Volatile material was removed by evaporation and the residue was dissolved in water (50 ml). The solution was washed with ethyl acetate and acidified to pH 4 with 1M citric acid solution. The resultant precipitate was collected by filtration to give 2,6-diethyl-1,4-dihydro-4-oxopyridine-3-carboxylic acid (E) (2.1 g), m.p. 238°-240° C. (decomposition); NMR (CDCl3): 1.3(t, 6H), 2.7(q, 2H), 3.3(q, 2H), 6.45(s, 1H), 12.1(br s, 1H).

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