4-Chloro-3-(2-chlorophenyl)-6-(methylthio)-1H-pyrazolo[3,4-d]pyrimidine synthesis

Yield:-

Reaction Conditions:

with N-ethyl-N,N-diisopropylamine;hydrazine in tetrahydrofuran at 0 - 20;

Steps:

1.3

Step 3. Preparation of 4-chloro-3-(2-chlorophenyl)-6-methylsulfanyl-1H-pyrazolo[3,4-d]pyrimidine; To a mixture of (2-chlorophenyl)-(4,6-dichloro-2-methylsulfanylpyrimidin-5-yl)-methanone (875 mg, 2.62 mmol) and N,N-diisopropyl ethyl amine (0.69 mL, 1.5 eq) in THF (20 mL) at 0° C. was added a solution of hydrazine (83 μL, 1 eq) in THF (20 mL) dropwise with stirring. After addition was complete, the reaction was gradually warmed to room temperature over 2 hours. Analysis by TLC indicated that there was still starting material remaining. Additional 3 mL of a solution of hydrazine (17 μL) in THF (10 mL) was added dropwise to the reaction mixture, and the reaction mixture was stirred at room temperature overnight. The reaction mixture was diluted with ethyl acetate (150 mL) and water (50 mL). The organic layer was separated, washed with water (4×50 mL) and brine (1×50 mL), dried over magnesium sulfate, filtered and concentrated to give the title compound as a yellowish powder (867 mg, (M+H)⁺=311).

References:

US2007/49597,2007,A1 Location in patent:Page/Page column 22