324028-89-9Relevant academic research and scientific papers
A 5, 6 - dimethoxy -2 - picolinic acid synthesis method
-
Paragraph 0010, (2019/02/13)
This invention relates to a 5, 6 - dimethoxy - 2 - pyridine carboxylic acid synthesis method. To solve the synthetic method on the reaction of high temperature, operation of the experiment is difficult, high requirements on equipment, unfavorable to industrialization production and amplification of the technical problem. The invention synthetic method comprises the following steps: 1st step, at room temperature, 2 - bromo - 3 - hydroxy pyridine in the potassium carbonate aqueous solution and hydrazine hydrate in the reaction, to obtain compound 1, product need purification, directly used for the next step reaction; 2nd step, compound 1 in N, N - dimethyl formamide and potassium carbonate in the reaction after adding methyl iodide, stirring overnight, to obtain compound 2; 3rd step, compound 2 and sodium methoxide in N, N - dimethyl formamide in reaction, bromine quilt methoxy selectively substituted, to obtain compound 3; 4th step, at the low temperature compound 3 and butyl lithium in tetrahydrofuran reaction, then added with the solid carbon dioxide, the reaction at room temperature, acidified by hydrochloric acid, to obtain the target compound 4, in petroleum ether and ethyl acetate mixed solvent recrystallization purification get the pure product.
