Oxolinic Acid → 3-Quinolinecarboxylic acid, 1,4-dihydro-6,7-dihydroxy-1-ethyl-4-oxo-

Participants

Reaction Steps

1.4-Dihydro-1-ethyl-6,7-methylenedioxy-4-oxoquinoline-3-carboxylic acid (3.9 g) and boron tribromide (15 ml) were heated at 50° C. for 15 hours. The reaction mixture was cooled and added slowly to water (100 ml) at 0° C. The pH was adjusted to 11 with concentrated potassium hydroxide, the mixture was filtered and the filtrate taken to pH1, whereupon the precipitate was collected by filtration, washed with water and dried to give 1,4-dihydro-6,7-dihydroxy-1-ethyl-4-oxoquinoline-3-carboxylic acid (3.13 g); δ ((CD3)2SO) 1.42(3H,t); 4.46(2H,q); 7.23(1H,s); 7.66(1H,s); 8.82(1H,s)ppm.

Provenance & Evidence