Tetrahydrofuran → 5-Norbornene-2-carboxylic acid

95.0 g (382 mmol) of the Diels-Alder adduct obtained in the above step was dissolved in 950 ml of tetrahydrofuran, 103 g (1.57 mol) of potassium hydroxide (85%) in 760 ml of water was added on ice cooling, and the mixture was stirred at room temperature for 24 hours. After tetrahydrofuran was distilled off from the reaction mixture, the residue was neutralized with 138 ml of concentrated hydrochloric acid, and the solution was extracted with a mixture solvent of hexane-methylene chloride (98:2) (200 ml×4). The extract was dried over anhydrous magnesium sulfate and filtered, the distilled off, and 45.0 g of crude 5-norbornene-2-carboxylic acid was obtained. Crude yield: 83%.

1. distillationAfter tetrahydrofuran was distilled off from the reaction mixture
2. extractionthe solution was extracted with a mixture solvent of hexane-methylene chloride (98:2) (200 ml×4)
3. dry with materialThe extract was dried over anhydrous magnesium sulfate
4. filtrationfiltered
5. distillationthe distilled off

ORD record

ord-b3f723c3e2834cffaf588b9c1342824e

Source dataset

uspto-grants-1993_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05266728