Yield:-

Reaction Conditions:

with sulfuric acid for 0.5 h;Heating;

Steps:

2.1. General procedure for the preparation of N-(benzo[d]thiazol-2-yl)-2-hydroxyquinoline-4-carboxamides and relevant derivatives (6a-l)

General procedure: Substituted 3-oxo-N-phenylbutanamides (1) (0.012 mol) was addedto concentrated sulfuric acid (0.001 mol) in portions on 75 °C to obtainsubstituted 4-methyl quinoline-2-ol (2) in an affordable yield range of92-98%. To 1.5 g (0.0094 mol) of 4-methyl quinoline-2-ol (2) in water,2.84 g (0.018 mol) of alk. KMnO4 was added with stirring for 4 h andkept on the water bath for 2 h till the color of the mixture changes tobrown. The reaction was then filtered and neutralized with 1:1 hydrochloricacid. The precipitate formed was washed with water anddried and recrystallized from hot water to obtain 2-hydroxyquinoline-4-carboxylic acid (3).

References:

Bindu;Vijayalakshmi;Manikandan [Bioorganic Chemistry,2019,vol. 91,art. no. 103171]