Preparation of 2,4-dichloro-5-methoxy pyrimidine

Abstract

The invention discloses a preparation method of 2, 4-dichloro-5-methoxypyrimidine, pertaining to the technical field of pesticide intermediate preparation. The method includes steps as follows: 2, 4-dihydroxy-5-methoxypyrimidine is prepared, and ethyl formate and solid sodium methoxide are added into a reaction device and stirred. After the temperature is lowered, methyl methoxyacetate is added for carrying out a condensation reaction to obtain a compound I, and then methanol and carbamide are added into the compound I and a refluxing reaction is carried out. A compound II is obtained after condensation, dissolution with water, cooling, neutralization, filtration and drying; the 2, 4-dichloro-5-methoxypyrimidine is prepared, and a chlorinating agent and an acid-binding agent are added into the compound II; and then a temperature reaction, dilution and filtration are carried out in sequence to obtain a crude product of the 2, 4-dichloro-5-methoxypyrimidine. The crude product is refined to obtain a pure product of the 2, 4-dichloro-5-methoxypyrimidine. The method has the advantages of easy availability of all raw materials, convenient synthesis, not exacting technological conditions, overall yield up to 57 percent to 67 percent, purity over 99.6 percent and applicability to industrialized production.

Description

technical field [0001] The invention belongs to the technical field of preparation of pesticide intermediates, and in particular relates to a preparation method of 2,4-dichloro-5-methoxypyrimidine. Background technique [0002] 2-Amino-5,8-dimethoxy[1,2,4]triazol[1,5-c]pyrimidine (DAT for short) is an important intermediate of a new herbicide with high efficiency, high efficiency and low toxicity. In the known preparation process of DAT, 2,4-dichloro-5-methoxypyrimidine needs to be used as a starting material. For example, the Chinese Invention Patent Authorization Announcement No. CN1172934C (ZL01811169.6) describes the use of 2,4-dichloro-5-methoxypyrimidine as a starting material, through hydrazination, ring closure and rearrangement to obtain DAT, but this patent does not Describe the synthesis method of 2,4-dichloro-5-methoxypyrimidine. At present, the domestic product (2,4-dichloro-5-methoxypyrimidine) mainly relies on imports, which is expensive, resulting in high DA...

AI Technical Summary

Problems solved by technology

For example, the Chinese Invention Patent Authorization Announcement No. CN1172934C (ZL01811169.6) describes the use of 2,4-dichloro-5-methoxypyrimidine as a starting material, through hydrazination, ring closure and rearrangement to obtain DAT, but this patent does not Describe the synthesis method of 2,4-dichloro-5-methoxypyrimidine. At present, the domestic product (2,4-dichloro-5-methoxypyrimidine) mainly relies on imports and is expensive, resulting in high DAT prices

The applicant conducted a comprehensive search, and found no technical inspiration for the synthesis of 2,4-dichloro-5-methoxypyrimidine in the literature

Images