Method for synthesizing 2-hydroxyl-4,6-dimethylpyrimidine

Abstract

The invention belongs to the field of chemical industry, relating to a preparation method of 2-hydroxyl-4,6-dimethylpyrimidine with sulfuric acid as catalyzer. The preparation method includes the following steps: (1) carbamide is put into the solvent of ethanol and is heated to dissolve; (2) 2,4-pentanedione is added to the carbamide solution, based on mol ratio of 1:1.0.5-1:1.10(carbamide: 2,4-pentanedione); (3) the mixture in step(2)is heated to 40-50 DEG C; (4) sulfuric acid is added drop by drop based on mol ratio of 1:0.7-1:0.8 (carbamide: sulfuric acid)and then the mixture reacts for 1-3h; (5)after the mixture cools, 2-hydroxyl-4,6-dimethylpyrimidine sulphate is separated out from the mixture through centrifugalization; (6) after being neutralized by alkali, 2-hydroxyl-4,6-dimethylpyrimidine sulphate is cooled and crystallized to get 2-hydroxyl-4,6-dimethylpyrimidine. The method is low in cost with mild condition and avoids the inconvenience in transportation and operation whenusing anhydrous chlorine hydride alcoholic solution as catalyzer during the preparation and greatly improves operational safety in summer. The quality of the 2-hydroxyl-4,6-dimethylpyrimidine prepared with the method satisfies the further requirements in preparing Anticoccidial Nicarbazin. The method is easy to be applied in industrial production.

Description

technical field [0001] The invention belongs to the technical field of applied chemistry and relates to a method for synthesizing 2-hydroxyl-4,6-dimethylpyrimidine. Background technique [0002] 2-Hydroxy-4,6-dimethylpyrimidine is referred to as HDP, which has a certain anti-coccidial effect. The activity was significantly better than the effect of the two used alone. There are many kinds of coccidia, and most chemically synthesized anticoccidial drugs will soon produce drug-resistant strains. Nicarbazine is one of the varieties that produce the least drug-resistant coccidian strains. Legal feed additive. [0003] 2-Hydroxy-4,6-dimethylpyrimidine was first synthesized by Evans in 1892, using the general method for the preparation of pyrimidine heterocycles, that is, the reaction of urea and 2,4-pentanedione under the catalysis of HCl to obtain HDP. HCl, and then neutralized by NaOH solution to obtain HDP containing two molecules of crystal water. [0004] It is difficult...

AI Technical Summary

Problems solved by technology

[0004] It is difficult to control the hydrogen chloride gas when it is added, so there is a patent that proposes to use the lower alcohol solution of HCl as a catalyst to prepare HDP. When it is higher, the solubility of HCl in alcohol becomes smaller, and when the pressure of HCl gas reaches a certain level, it may rush out of the container, causing a safety accident

At the same time, the content of HCl in alcohol is not easy to increase, and it is difficult to reach more than 30%. At the same time, because HCl is very easy to absorb water, the lower alcohol solution of HCl often contains a certain amount of water, which has a certain negative impact on the reaction.

Considering the constraints of the above factors, the actual production cost and difficulty are relatively high, and it is difficult to reach the ideal level of the laboratory