Preparation of 2-ethoxy-4-acetaminobenzoic acid methyl ester

Abstract

A preparation method for 1.2-oxethyl-4-acetamido methyl benzoate comprises the following steps that 2-hydroxyl-4-nitrobenzoic acid is taken as a raw material, is dissolved in 4 to 5mol of methanol as calculated by raw material per mol and is added with 5 to 10g of catalyst; the mixture is heated and undergoes back flow; when reaction is carried out for 3 hours, the catalyst is filtered out; hydrogenation reduction of nitro is carried out under a pressure of 0.3MPa and at a temperature of 50 DEG C; the temperature is controlled between 25 and 35 DEG C; according to a proportion that 1mol acetic anhydride is dripped into every mol of the raw material, acetic anhydride is dripped and stirred at a temperature of between 40 and 50 DEG C for 40min; the mixture is cooled down to room temperature after solidifying; according to a proportion that 200 to 300ml of water is added in every mol of the raw material, water is added and stirred, and acetylated solid can be obtained after sucking filtration and drying; the acetylated solid product obtained from each mol of raw material is dissolved in 100ml of DMF, and 1mol of potassium carbonate and 1mol of CH3CH2Br are added and stirred at a temperature of between 50 and 60 DEG C for 3 hours; the reactants are poured with ice water so as to obtain a brown solid after filtration; normal hexane and toluene with the volume ratio equal to 1 to 1 are used to dissolve the brown solid; and after heated back flow and recrystallization, a silvery white 1.2-oxethyl-4-acetamido methyl benzoate solid can be obtained.

Description

technical field [0001] The invention belongs to the technical field of chemical industry and pharmacy, and relates to a preparation method of veterinary drug 2-ethoxy-4-acetamidobenzoic acid methyl ester. Background technique [0002] Methyl 2-ethoxy-4-acetamidobenzoate is a broad-spectrum anticoccidial veterinary drug and an important feed additive. This drug was listed abroad in the early 1970s, but there is still no mass production in China at present, mainly relying on imports. At present, the widely used method is mainly to use p-aminosalicylic acid through methylation, acetylation, and etherification (GB1019781; Feed Industry, 2002, 23 (6): 37-38), and diethyl sulfate is used as etherification. reagent. This method reaction time is too long, and operational route is more complicated, and yield is low, and diethyl sulfate toxicity is bigger. Si Zongxing et al. (Chemical Bulletin, 1998 (5) 58-59) improved the synthesis process by using methyl iodide as an etherificati...

AI Technical Summary

Problems solved by technology

The reaction time of the method is too long, the process route is more complicated, the yield is low, and diethyl sulfate is more toxic

Si Zongxing et al. (Chemical Bulletin, 1998 (5) 58-59) improved the synthesis process and adopted methyl iodide as etherification reagent. The raw material methyl iodide of this method is expensive, which greatly reduces its industrial feasibility

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