Trifluoroacetic acid → 4-(4-methanesulfonyl-phenoxy)-1-piperidin-4-yl-1H-pyrazolo[3,4-d]pyrimidine trifluoroacetate salt

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Reaction Steps

Trifluoroacetic acid (38.0 mL, 512 mmol) was added to a cooled solution of 4-[4-(4-methanesulfonyl-phenoxy)-pyrazolo[3,4-d]pyrimidin-1-yl]-piperidine-1-carboxylic acid tert-butyl ester (Example 59; 12.0 g, 25.4 mmol) in dichloromethane (70 mL) at about 0° C. The reaction mixture was stirred for 3 h. The solvent was evaporated under reduced pressure, and the residue was coevaporated three times with toluene to give 4-(4-methanesulfonyl-phenoxy)-1-piperidin-4-yl-1H-pyrazolo[3,4-d]pyrimidine trifluoroacetate salt (12.0 g, 97%) as an off-white solid which was used in the next step without further purification. 1H NMR (300 MHz, DMSO-d6) δ 2.14-2.17 (m, 2H), 2.32-2.41 (m, 2H), 3.22-3.30 (m, 2H), 3.30 (methyl sulfonyl peak and water peak), 3.45-3.50 (m, 2H), 5.15-5.21 (m, 1H), 7.62-7.64 (m, 2H), 8.06-8.08 (m, 2H), 8.44 (s, 1H), 8.50-8.58 (br s, 1H), 8.59 (s, 1H), 8.76-8.83 (br s, 1H). Mass spectrum (ES) MH+=374.

Provenance & Evidence