Abstract:
An improved procedure for the preparation of 2,4-dihydroxy quinoline has been standardised. The process consists of (i) condensation of methyl anthranilate in presence of a base catalyst with acetoacetic ester and (ii) cyclisation of O-carbomethoxy N-acetoacetanilide followed by -(iii) deacetylation of the cyclised 3-acetyl quinoline to 2,4-dihydroxy quinoline. The yield of the product is 75-80% based on methyl anthranilate.