K. Avasthi et al., A CONVENIENT SYNTHESIS OF 1 2-VINYL-1H/2H-PYRAZOLO[3,4-D]PYRIMIDINES - ANALOGS OF 9-VINYLPURINES/, Indian journal of chemistry. Sect. B: organic chemistry, including medical chemistry, 34(3), 1995, pp. 173-177
A convenient general synthesis of N-1- and N-2-vinyl-1H/2H-pyrazolo[3,
4-d]pyrimidines and their conversion to 4-amino-N-1-, 4-amino-N-2-, 4-
(5H)oxo-N-1- and 5H)-oxo-N-2-vinyl-1H/2H-pyrazolo[3,4-d]pyrimidines ha
ve been reported.