1-Pyrazolo pyrazines pyrazoles

Pyrazolo[3,4-b]pyrazines are useful intermediates for the preparation of 2-aminopyrazine-3-carboxamides such as 49, much used in pteridine syntheses. For example, reductive cleavage of the 1-substituted 3-hydroxy compound 48 with Raney nickel results in smooth breakdown of the pyrazole ring to give the product 49. 

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