Diethyl Oxalate → HCID 67400374, compound

Participants

Reaction Steps

20.4 g of diisopropylamine (0.1 mol) were dissolved in 200 ml of dry THF under nitrogen and cooled in a freezing mixture. 80 ml n-butyllithium in hexane (2.5 M, 0.2 mol) were added dropwise slowly. After the addition it was allowed to stir for 60 minutes and then 22.6 g N-methyl-2-piperidone (0.2 mol) were added dropwise. The reaction mixture was stirred for another 20 min in the freezing mixture. In a second flask, 87.7 g diethyl oxalate (0.6 mol) in 100 ml of dry THF were cooled in a freezing mixture and the cooled reaction mixture was cannulated with stirring in small portions to it. It was left overnight under stirring to warm to room temperature. The THF was removed on a rotary evaporator and the residue was taken up in 80 ml half concentrated hydrochloric acid. The aqueous phase was extracted five times with 300 ml ethyl acetate, the combined organic phases were dried over sodium sulfate and concentrated on a rotary evaporator to dryness. The excess diethyl oxalate was removed by distillation (2-3 mbar, 80° C.) and 45 g of crude product were obtained. 10.4 g product was obtained as white crystals with a melting point of 23° C. after crystallization from diethyl ether/n-hexane.

Provenance & Evidence