4-Deoxypyridoxine (Ⅰ) is an effective antagonist of pyridoxine, and also a biochemical reagent.It possesses antitumour effect in pyridoxine-deficient animals.In this investigation a new route for the synthesis of Ⅰ has been described.The starting material is o-aminoacetophenone (Ⅱ), which in turn is obtained from o-nitroethylbenzenc,a by-product in the production of certain drugs.Ⅱ condenses with bromoacetonc in dilute alcohol in the presence of potassium hydroxide to give 2,4-dimethyl-3-hydroxyquinoline (Ⅲ).The latter is ethylated with ethyl iodide to afford 2,4-dimethyl-3-ethoxyquinolinc hydrochloride (Ⅳ), which is then converted to 2,4-dimethyl-3-ethoxypyridine-5,6-dicar-boxylic acid (Ⅷ) via two routes:(1) Ⅳ is oxidized directly with potassium permanganate in aqueous potassium carbonate solution, and (2) Ⅳ is converted to a nitro deriva-five (Ⅴ), then catalytically hydrogenated to an amino compound and finally oxidized to Ⅶ by potassium permanganate.VII is decarboxylated and then estcriEied with diazomc-thane to give the corresponding methyl ester (Ⅸ).Upon reduction with lithium aluminium hydride the ester is converted to 2,4-dimethyl-3-ethoxy-5-hydroxymethylpyridinc hydrochloride (Ⅹ) which upon treating with dilute hydrochloric acid in a sealed tube at 200-205°, yields the desired product (Ⅰ).