2-Methyl-3-quinolinecarboxylic acid

To a stirred solution of potassium hydroxide (4.489 g, 80 mmol) in 60percent ethanol aqueous solution (80 mL) was added ethyl 2-methylquinoline-3-carboxylate (2.153 g, 10 mmol). The reaction mixture was stirred under reflux for 1 h. After removal of the ethanol under vacuum, water (10 mL) was added and acidified with 1 M HCl solution. The resultant precipitates were collected and crystallized from dichloromethane/hexane (1/10, v:v) to afford 2-methylquinoline-3-carboxylic acid in 92percent yield (1.724 g, 9.2 mmol) as a yellow solid.To a stirred solution of 2-aminobenzaldehyde (1a, 206 mg, 1.70 mmol) in 15 mL of toluene, was added methyl acetoacetate (2a, 217 mg, 1.87 mmol, 1.1 equiv) and the solution was refluxed for 24 h during which time a light tan precipitate formed. The reaction mixture was cooled to room temperature, evaporated to one-half its volume, and then cooled to 0 °C using an ice bath. The solid was filtered and washed with 1:1 ether:hexane to give acid 3a. The compound obtained was spectroscopically pure and no further purification was necessary. Note: The reaction was also carried out using xylene as the solvent and no change in the yield or purity was observed. Reactions run in benzene, however, gave mixtures of the acid and its corresponding ester.

Molecular Weight:187.19
XLogP3:2.1
Hydrogen Bond Donor Count:1
Hydrogen Bond Acceptor Count:3
Rotatable Bond Count:1
Exact Mass:187.063328530
Monoisotopic Mass:187.063328530
Topological Polar Surface Area:50.2
Heavy Atom Count:14
Complexity:229
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes