Ethyl 2-chloroacetoacetate → 5-Ethyl-2-methyl-nicotinic acid ethyl ester

関与物質

反応手順

A suspension of 2 kg of ammonium acetate (26 moles) in 4.5 L of acetic acid is mechanically stirred in a 12 L 4-necked flask equipped with a condenser, and treated with 1 kg of 2-ethylacrolein (11.9 moles) in a single portion followed by 2 kg of ethyl 2-chloroacetoacetate (12.1 moles). An exotherm ensues over a period of 5 minutes to the boiling point of the solvent; this condition is maintained (under control) with air cooling for 10 minutes. After stirring overnight at ambient temperatures, the reaction mixture is filtered, the filtrate is concentrated in vacuo, and the residue is partitioned between 2:1 hexane-ethyl acetate and water. The organic phase is washed with water, then extracted thoroughly with 5% aqueous HCl. The combined aqueous extracts are washed with 2:1 hexane-ethyl acetate, made basic with concentrated NH2OH, and extracted with 2:1 hexane-ethyl acetate. The combined organic extracts are dried and concentrated in vacuo, to give an oil residue which is vacuum distilled to afford 1.4 kg of the title product, bp 90°/0.05 mm.

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