Ethanol → 1H-Pyrazolo(3,4-d)pyrimidine

Participants

Reaction Steps

Analogously to Example 5, 436 mg (2.3 mmol) of N-ethoxycarbonyl-(D/L)-valine [prepared from (D/L)-valine as described in J. Org. Chem. 60, 7256 (1995)] in 4.8 ml of THF and 506 μl (4.6 mmol) of NMM are activated with 349 μl (2.6 mmol) of isobutyl chloroformate and then reacted with 600 mg (2.3 mmol) of 3-amino-4-(3-chloro-phenylamino)-1H-pyrazolo[3,4-d]pyrimidine (see Step 1.6). Dissolution in DMSO (2 ml) at 100° C., addition of 25 ml of ethanol and cooling yield rac.-4-(3-chloro-phenylamino)-3{N-ethoxycarbonyl-valyl)-amino}-1H-pyrazolo[3,4-d]pyrimidine; HPLC: tRet(grad20-100/20)=13.2; FAB-MS: (M+H)+=432.

Provenance & Evidence