反应详情

A mixture of 3-amino-2-methylbenzoic acid (Intermediate M1) (6.06 g, 39.6 mmol) (commercially available from Aldrich) and arsenic acid (H5As3O10) 7.43 g (commercially available from VWR/ALFA) in glycerol (5.8 mL, 79.2 mmol), and sulfuric acid (9 mL) was heated to 160° C. for 5 h. The mixture was cooled to rt, diluted with water and filtered through a bed of diatomaceous earth. The pH was adjusted to pH 6-7 with 2 M NaOH. The aqueous layer was exhaustively extracted with CHCl3:MeOH (3:1). The organic fractions were pooled and evaporated under vacuum to give a solid. This solid was titurated with CHCl3, and collected on a glass frit. The solid material was washed with hexanes and dried under high vacuum to give a pure solid, 8-methylquinoline-7-carboxylic acid (Intermediate M2) 3.86 g (51%).

1. filtrationfiltered through a bed of diatomaceous earth
2. extractionThe aqueous layer was exhaustively extracted with CHCl3:MeOH (3:1)
3. customevaporated under vacuum
4. customto give a solid
5. customcollected on a glass frit
6. washThe solid material was washed with hexanes
7. customdried under high vacuum