反应详情

3.84 g of methanesulfonic acid are added at 20°±3° C. to a solution of 18.55 g of the compound obtained in example 195 in 185 ml of acetone and the mixture is stirred for 20 hours at the same temperature. The white crystals formed are filtered off, washed with acetone and dried under vacuum to give 21.65 g of the expected product. DSC: melting, recrystallisation at about 175° C. then melting at 191.5° C. Thermogravimetry: weight less:about 5.2 % starting at 90° C.

1. customThe white crystals formed
2. filtrationare filtered off
3. washwashed with acetone
4. customdried under vacuum