Method for synthesizing [(4-amino-3,5-dichloro-6-fluoro-2-pyridinyl)oxy]acetic acid by using one-pot method

Abstract

The invention discloses a method for synthesizing [(4-amino-3,5-dichloro-6-fluoro-2-pyridinyl)oxy]acetic acid by using a one-pot method. The method comprises the following steps of: carrying out esterification reaction between glycolic acid and DL-2-Octanol under the action of a catalyst (I), subsequently feeding [(4-amino-3,5-dichloro-6-fluoro-2-pyridinyl)oxy]acetic acid, an acid-binding agent and a catalyst (II), heating and keeping the temperature till the condensation reaction is completely accomplished, and carrying out aftertreatment so as to obtain [(4-amino-3,5-dichloro-6-fluoro-2-pyridinyl)oxy]acetic acid. The method has the beneficial effects that firstly, the five main steps of the conventional preparation method are reduced to three steps, and the catalysts are introduced, so that the yield is kept be at a higher level, the raw material consumption is reduced, and the cost is lowered; secondly, the steps of separation and drying are canceled, so that the equipment consumption and the energy consumption are reduced, and no pyridol compounds which have serious pollution to the environment are generated, thereby being environmental-friendly; and thirdly, the preparation method is simple in process, simple and convenient to operate and high in yield, and is applicable to large-scale industrial production.

Description

technical field [0001] The invention relates to the technical field of fine chemicals, in particular to a method for synthesizing fluroxypyr sec-octyl ester in one pot. Background technique [0002] 1-Methylheptyl (4-amino-3,5-dichloro-6-fluoro-2-pyridyloxy) acetate (also known as fluroxypyr 2-octyl) is produced by Dow Agrochemicals The developed organic heterocyclic herbicide is a typical hormone-type herbicide, which can be quickly absorbed by plant leaves and roots, and can be quickly transmitted in the body. Suitable for controlling broad-leaved weeds in wheat, barley, corn, grapes, orchards, pastures, woodlands, lawns, etc. Amaranth, etc., are ineffective against grass weeds. [0003] As a high-efficiency, low-toxicity and low-residue herbicide containing fluorine, fluroxypyr sec-octyl ester is the development direction of new herbicides today. Because of its high safety to crops in and after stubble, wide application period, fast drug effect, low dosage, and good co...

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Problems solved by technology

U.S. patent document US3755339 discloses the preparation method of substituted pyridinol and chloroacetate condensation, and this method yield is lower; The yield of the condensation step, but derivatization has brought unnecessary operation and raw material consumption; U.S. patent document US3969360 discloses the preparation method utilizing substituted pyridinol sodium salt and chloroacetate condensation, has improved yield, but has brought Separation, drying and environmental protection issues; U.S. patent document US4108629 discloses the preparation method of the direct condensation of fluorinated pyridine and glycolate, but this patent does not provide the preparation method of glycolate, and the reaction yield is also low; Patent document US5214150 discloses the preparation method of transesterification after condensation of substituted pyridinol sodium salt and lower chloroacetate, although the reaction yield has been further improved, there are still problems of separation, drying and environmental protection

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