5337-04-2

5382-77-4

5337-04-2

General procedure for the synthesis of 4,4-tetrahydropyranodicarboxylic acid from diethyl dihydro-2H-pyran-4,4(3H)-dicarboxylate: diethyl tetrahydro-2H-pyran-4,4-dicarboxylate (4.04 g, 20 mmol) was suspended in 30% aqueous sodium hydroxide (10 mL) and the reaction was stirred at room temperature for 28 hours. Upon completion of the reaction, the pH of the reaction solution was adjusted with concentrated hydrochloric acid to 1. Subsequently, appropriate amount of hydrochloric acid was added and the mixture was partitioned between water and ethyl acetate for extraction. The organic layer was dried with anhydrous sodium sulfate and concentrated under reduced pressure to remove the solvent. To the resulting crude product, ethyl acetate (30 mL) was added, the mixture was washed by repurification, the solid product was collected by filtration and dried to give tetrahydro-4H-pyran-4,4-dicarboxylic acid (3.19 g, 18.3 mmol, 92% yield). The product was characterized by 1H-NMR (DMSO-d6): δ 1.90 (4H, t, J = 5.3 Hz), 3.55 (4H, t, J = 5.3 Hz), 12.93 (2H, s).