Methanol → p-Toluenesulfonic acid

Participants

Reaction Steps

Compound C (250 mg, prepared in analogous fashion to the process described in Example 12 above) was dissolved in methanol (10 mL). Toluenesulphonic acid (110 mg) was added to the solution. The methanol was removed under reduced pressure and the remaining gum was re-dissolved in the minimum amount of hot ethyl acetate possible. The solution was seeded with previously prepared salt (prepared by slow evaporation of solvent from a small portion of a solution of title compound, prepared in analogous fashion to this procedure) and left in the fridge for several days to crystallise. The resulting crystals were collected by filtration and washed with a small amount of cold ethyl acetate (recovered 280 mg, 78%).

Provenance & Evidence