Hydrochloric Acid → 2-Pentyl-3-methoxy-2-cyclopentenone

Participants

Reaction Conditions

Reaction Steps

To 32.5 g (0.19 mol) of 2-n-pentyl-1,3-cyclopentanedione was added 650 ml of methanol containing 1 wt % of hydrogen chloride (prepared by preliminarily blowing hydrogen chloride therein), followed by heating under reflux for 5 hours and cooling to 25° C. Then, thereto was gradually added 15.4 g of sodium hydrogencarbonate followed by stirring for 30 minutes at 25° C. Methanol was distilled off in vacuo and then 200 mL of water and 200 mL of isobutanol were added. The resulting mixture was stirred for 10 minutes at 25° C. and then allowed to stand to separate the organic phase. Isobutanol in the organic phase was distilled off, yielding 2-pentyl-3-methoxy-2-cyclopentenone (a compound in which R20 represents an n-pentyl group, and R21 represents a methyl group in the above formula (14)). Gas chromatographic analysis showed that the yield of 2-pentyl-3-methoxy-2-cyclopentenone relative to 2-n-pentyl-1,3-cyclopentanedione was 80%.

Provenance & Evidence