Hydrazine → tert-Butyl 3-amino-1,4,6,7-tetrahydro-5H-pyrazolo[4,3-c]pyridine-5-carboxylate

Participants

Reaction Conditions

Reaction Steps

To a solution of 141.5 g of 3-cyano-4-hydroxy-1,2,5,6-tetrahydropyridine-1-carboxylic acid tert-butyl ester in 1.2 L of ethanol were added under stirring 57.8 mL of aqueous 35% hydrazine. The mixture was heated at 70° C. for 4 h. The solution was evaporated at under vacuum, the residue was diluted with 1 L of water and extracted with ethyl acetate. The combined organic extracts were washed with brine, dried over sodium sulfate and evaporated to dryness. The crude product was taken-up with 300 mL tert-butyl methyl ether and the crystallized compound was collected by filtration to give 115.6 g of the title compound.

Provenance & Evidence