4H-Pyrazolo[4,3-c]pyridin-4-one, 3-amino-1,5-dihydro- synthesis

Yield:-

Reaction Conditions:

with hydrazine at 140; for 18 h;Neat (no solvent);

Steps:

3 3-Amino-1H-pyrazolo[4,3-c]pyrid-4-ol

3-Amino-1H-pyrazolo[4,3-c]pyrid-4-ol A mixture of 1.2 g of 2-hydroxy-4-methoxynicotinonitrile and 30 mL of hydrazine hydrate is maintained at 140° C. for 18 hours in a bomb. The reaction medium is then evaporated to dryness. The residue is taken up in ethyl ether, and the resulting suspension is filtered. 1.1 g of 3-amino-1H-pyrazolo[4,3-c]pyrid-4-ol are obtained in the form of a grey solid. MS: 150⁺=M^+°; m.p.=240° C. dec. (K?fler).

References:

US2008/39491,2008,A1 Location in patent:Page/Page column 14