Hydrazine → 2-(3-Hydroxy-4-benzoylphenoxy)ethyl Carbazate

Participants

Reaction Steps

Into a 250 ml 3-neck flask was added 5.4 grams (0.11 mole) of 64% aqueous hydrazine and 50 mls of THF. The flask was equipped with a magnetic stirrer, thermometer, reflux condenser and a dropping funnel containing 9.6 grams (0.03 mole) of 2-(3-hydroxy-4-benzoylphenoxy)ethyl chloroformate dissolved in 50 ml of THF. The chloroformate solution was added dropwise to the stirring hydrazine solution over 1/2 hour. The temperature quickly exothermed to 36° C. and slowly subsided after the addition was over. The reaction was stirred an additional 1/2 hour and concentrated to 31 grams. The THF solution was added to 300 ml of water. A sticky solid formed. The solid was filtered off, taken up in methylene chloride, dried over Na2SO4, filtered and the methylene chloride stripped off. The residue was a viscous orange-brown liquid. The crude product was slurried in 150 ml of warm MtBE. Most of the crude product went into solution, leaving a dark brown liquid residue. The yellow MtBE layer was decanted off and the MtBE stripped off on a rotating evaporator, leaving 9.0 grams of a yellow viscous liquid. Liquid chromatography indicated it was about 92% pure. The residue was slurried in warm methanol and upon cooling, a solid formed. The solid was filtered off and after air drying, weighed 6.4 grams (67% yield) and had a melting point of 58°-61° C.

Provenance & Evidence