Synthesis
Step 2: Phosphorus trichloride (237.2 g, 1.55 mol) was added dropwise to stirred N,N-dimethylformamide (40.4 g, 552.74 mmol) at 0 °C. N-p-tolylacetamide (33 g, 221.19 mmol) was subsequently added and the reaction mixture was kept stirring at reflux temperature overnight. Upon completion of the reaction, the reaction was quenched with 3000 mL of H2O/ice mixture. The pH of the mixture was adjusted to 9 by addition of Na2CO3. The reaction mixture was extracted with dichloromethane (3 x 3000 mL). The organic phases were combined and dried over anhydrous MgSO4 and subsequently concentrated under reduced pressure on a rotary evaporator. The crude product was purified by silica gel column chromatography with an eluent ratio of 1:10 ethyl acetate:hexane to give 15.3 g (34% yield) of 2-chloro-6-methylquinoline-3-carboxaldehyde as a yellow solid.LCMS detection showed a molecular ion peak of 206 (M + H)+.
References
[1] Synlett, 2001, # 2, p. 251 - 253
[2] Patent: CN104774221, 2017, B. Location in patent: Paragraph 0062
[3] Patent: CN104725431, 2017, B. Location in patent: Paragraph 0050
[4] Synthetic Communications, 2002, vol. 32, # 9, p. 1351 - 1356
[5] Journal of the Brazilian Chemical Society, 2014, vol. 25, # 2, p. 365 - 371
