4630-80-2

67-56-1

3400-45-1

4630-80-2

Cyclopentanecarboxylic acid (9.5 mL, 87.6 mmol) was dissolved in anhydrous CH2Cl2 (100 mL) in an oven-dried flask equipped with anhydrous CaCl2 drying tube. Subsequently, oxalyl chloride (8.8 mL, 105.1 mmol) was slowly added dropwise and 2 drops of DMF was added as a catalyst. After the reaction was carried out for 7 hours, the mixture was concentrated under vacuum. The concentrated residue was dissolved in MeOH (25 mL) and the reaction was continued for 19 hours. After completion of the reaction, the mixture was again concentrated under vacuum. The residue was redissolved in CH2Cl2 (100 mL) and washed sequentially with saturated NaHCO3 solution and brine. The organic layers were combined, dried with anhydrous Na2SO4, filtered and concentrated under vacuum. Finally, the residue was purified by simple distillation to afford methyl cyclopentanoate (9.5 g, 74.3 mmol, 85% yield) as a colorless oil.