Benzoic Acid → Linagliptin benzoate

Participants

Reaction Conditions

Reaction Steps

A mixture of 2.50 g Linagliptin free base in 20 ml isopropanol was heated to reflux. To the hot suspension 646 mg benzoic acid dissolved in 5 ml isopropanol were added. The mixture was allowed to cool to about 25° C. and further stirred at the same temperature for about 7.5 hours. The solid was isolated by filtration and dried at 40° C. for about 13 hours to obtain 2.94 g crystalline Linagliptin benzoate of WO2010/072776 A1, which was confirmed to be Linagliptin benzoate form I by XRPD.

Provenance & Evidence