4-[4-Fluoro-2-((S)-1-methanesulfonyl-piperidin-3-yloxy)-phenylamino]-5-methyl-thieno[2,3-d]pyrimidine-6-carboxylic acid methyl ester (130 mg) was dissolved in THF (3 ml) and a solution of lithium hydroxide* H2O (60 mg) in water (3 ml) was added. The mixture was stirred for 4 h. HCl (2M) was added to adjusted to pH 5 and the volatile solvent partially removed until crystallization occurred. The solid was collected by filtration. The filter cake was washed with water and was dried to give the desired product.
