Hydrazine → Oxane-4-carbohydrazide

A solution of methyl tetrahydro-2H-pyran-4-carboxylate (1.44 g, 10.0 mmol) in methanol (50 mL) was stirred at 50° C. To the reaction mixture, hydrazine.monohydrate (0.675 g) was added, followed by stirring at the same temperature for 2 hours, after completion of the reaction, the reaction mixture was concentrated and diluted with methylene chloride, the solution was then washed with saturated sodium bicarbonate aqueous solution and saturated brine, and the organic layer was dried over magnesium sulfate and the solvent was distilled off under reduced pressure to afford 952 mg of the title compound (yield 66.1%).