2-Methyl-2-butene → 5-Phenylfuran-2-carboxylic acid

To a solution of the product from Step 103a (0.650 g, 3.78 mmol, 1 eq) in water (5.5 mL), t-BuOH (18.0 mL), and THF (18.0.mL) is added 2-methyl-2-butene (3.2 mL, 30.2 mmol, 8 eq), potassium phosphate monobasic (1.54 g, 11.3 mmol, 3 eq), then NaClO2 (1.03 g, 11.3 mmol, 3 eq) in that order. After four hours, the reaction is complete and diluted with 1 N NaOH (100 mL). The aqueous solution is extracted with ether (2×100 mL), and the aqueous layer is acidified with conc. HCl. The resulting solution is extracted with CH2Cl2 (3×100 mL). The organic layers are dried over MgSO4, and the solvent removed. The product is purified by silica gel chromatography using a Biotage Flash 40M column (10% EtOAc/1% formic acid/heptane). The solid remaining after removal of the solvent is filtered and recrystallized from EtOH and water to give the acid as a white crystalline solid (0.499 g, 70.2%). HRMS (FAB) calculated for C11H8O3+H 189.0473, found 189.0403.

1. extractionThe aqueous solution is extracted with ether (2×100 mL)
2. extractionThe resulting solution is extracted with CH2Cl2 (3×100 mL)
3. dry with materialThe organic layers are dried over MgSO4
4. customthe solvent removed
5. customThe product is purified by silica gel chromatography
6. customafter removal of the solvent
7. filtrationis filtered
8. customrecrystallized from EtOH and water

ORD record

ord-a671e5153f1947bd8e49734612651e1c

Source dataset

uspto-grants-2002_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06500840B2