Sulfuric Acid → 5,7-Difluoro-1,2-dihydroquinolin-2-one

Participants

Reaction Conditions

Reaction Steps

A solution of 70% H2SO4 was made up by adding chilled H2SO4 (70 ml) to chilled water (30 ml) ensuring the temp remained between 10-20° C. The acid was then slowly added to the water keeping the temperature between 10 and 20° C. Finely ground N-(3,5-difluorophenyl)-3,3-bis(methyloxy)propanamide (12 g, 49 mmol) was added to the chilled solution over 1 h and then stirred at 5° C. for 1.5 h. An ice-water mixture (100 ml) was added carefully, followed by water (400 ml). The mixture was stirred for 0.5 h then the solid formed was filtered off and dried in the vacuum-oven at 40° C. over the weekend. The solid was still wet so it was dried in the desiccator with P2O5 to afford the impure desired compound (12 g, 136%).

Provenance & Evidence