6-methyl-1H-pyrazolo[3,4-d]pyrimidine synthesis

Yield:-

Reaction Conditions:

with 20% palladium hydroxide-activated charcoal;hydrogen;triethylamine in 1,4-dioxane;ethyl acetate at 20; under 2250.23 Torr; for 51 h;

Steps:

23A 6-Methyl-1H-pyrazolo[3,4-d]pyrimidine

4.464 g (approx. 24.28 mmol, purity 92%) of 4-chloro-6-methyl-1H-pyrazolo[3,4-d]pyrimidine were dissolved in 180 ml of dioxane, 2.948 g (29.14 mmol) of triethylamine and 5.629 g of 20% palladium hydroxide on carbon were added, and hydrogenation was effected with hydrogen at 3 bar and RT for 2 d. 100 ml of ethyl acetate, 2.948 g (29.14 mmol) of triethylamine and 2.000 g of 20% palladium hydroxide on carbon were added.
The mixture was hydrogenated with hydrogen at 3 bar and RT for 3 h.
The mixture was filtered through Celite and washed with a little dioxane/ethyl acetate, and the filtrate was concentrated on a rotary evaporator. 2.180 g (purity 73%, 49% of theory) of the target compound were obtained.
LC-MS (Method 3): R_t=0.40 min; MS (ESIpos): m/z=135 (M+H)⁺

References:

US2013/210824,2013,A1 Location in patent:Paragraph 0544; 0545; 0546