1 results about "Chloral hydrate" patented technology

The present application relates to the chemical technology field, specifically to a kind of preparation method of high-purity o-vanillin.The method uses o-methoxyphenylamine as starting material, with chloral hydrate and hydroxylamine hydrochloride is condensed, hydroxylamine oximation reaction, and cyclization reaction is carried out under strong acid condition, and compound 2 is generated;Compound 2 is oxidized under strong base condition, and compound 3 is generated;Compound 3 is esterified with primary alcohol to generate corresponding ester, and then reduction hydrogenation reaction is carried out under the action of strong reducing agent, and compound 4 is generated;Compound 4 is reacted with oxidizing agent in the presence of nitroxyl radical catalyst, and compound 5 is generated;Compound 5 carries out diazotization hydrolysis reaction, and o-vanillin is generated.The method avoids the problem of regioselectivity of traditional formylation reaction through specific reaction sequence, eliminates the generation of isomer impurities from the source, realizes the efficient, environmentally friendly, economic synthesis of high-purity o-vanillin, and provides high-quality raw material guarantee for downstream pharmaceutical.