Oxalic Acid → 2-Pentylidenecyclopentanone

Participants

Reaction Steps

In a 300 ml four-neck flask fitted with a thermometer, a reflux condenser and a stirrer were placed 2-(1-hydroxypentyl)cyclopentanone (70 g) synthesized in Reference Example 1, oxalic acid (0.7 g) and toluene (140 ml), and the whole was refluxed to allow dehydration to proceed. The formed water was removed and the reaction was continued until water was not formed any more (about 2.5 hours). The reaction mixture was washed with water and the layers were separated from each other. The resulting organic layer was further washed with saturated brine and separated. The organic layer was evaporated on a rotary evaporator under reduced pressure to recover toluene and unreacted cyclopentanone, whereby a crude product (63 g) was obtained. The product was distilled using a Widmer distillation apparatus to obtain 52 g of 2-pentylidenecyclopentanone (boiling point: 92° C./533 Pa).

Provenance & Evidence