Water → 6-hydroxychroman-2-carboxylic Acid

Reaction equation

C[O:2][C:3]1[CH:4]=[C:5]2[C:10](=[CH:11][CH:12]=1)[O:9][CH:8]([C:13]([OH:15])=[O:14])[CH2:7][CH2:6]2.Cl.[NH+]1C=CC=CC=1.O>CCOC(C)=O>[OH:2][C:3]1[CH:4]=[C:5]2[C:10](=[CH:11][CH:12]=1)[O:9][CH:8]([C:13]([OH:15])=[O:14])[CH2:7][CH2:6]2

Participants

Procedure

(RS)-6-Methoxy-chroman-2-carboxylic acid (1.12 g, 5.37 mmol) and pyridinium hydrochloride (11.2 g, 96.6 mmol) were heated together at 180° C. for 2 hr under argon with stirring. After cooling to ambient temperature H2O (100 ml) and EtOAc (50 ml) was added and shaken. The aqueous phase was extracted with EtOAc (50 ml) and the combined organic extracts were washed with satd. NaCl solution (50 ml) and then dried with Na2SO4 and evaporated to afford (RS)-6-hydroxy-chroman-2-carboxylic acid as white crystals (0.94 g, 4.84 mmol, 90%) Mp. 175-177° C., MS m/e=194.1 (M+).