Ethanol → Rifaximin

Participants

Reaction Conditions

Reaction Steps

Rifamycin O (50 g) and 76 ml of ethanol were stirred in a RBF at 20-30° C., for 15 minutes, DM water (100 ml) and 21.5 g of 2-Amino-4-picoline were added and stirred for 15 minutes at 25-30° C. The reaction mass was heated to 47° C. and stirred for 4-5 hours. Reaction mass was cooled to 20° C. and a solution of 1.32 g of ascorbic acid in 10 ml of concentrated HCl and 7.1 ml of DM water was added into it in 30 minutes. The reaction mixture was stirred for 30 minutes at 20° C.; ˜8.75 ml of concentrated HCl was added into it to adjust the pH to 1.5-2.0 and further stirred. The crude was isolated by filtration, washed with 100 ml of 1:1 Ethanol and water mixture. The Crude was pulped with DM water until the pH of filtrate is neutral, dried for 10-12 hours at 70° C. until the moisture content was <5.0%.

Provenance & Evidence