Hydrochloric Acid → 3,4-dihydro-2H-chromene-6-carboxylic acid
Reaktionsgleichung
[O:1]1[C:10]2[C:5](=[CH:6][C:7]([C:11](=[O:13])C)=[CH:8][CH:9]=2)[CH2:4][CH2:3][CH2:2]1.Cl[O-].[Na+].S(=O)(O)[O-:18].[Na+].Cl>>[O:1]1[C:10]2[C:5](=[CH:6][C:7]([C:11]([OH:13])=[O:18])=[CH:8][CH:9]=2)[CH2:4][CH2:3][CH2:2]1Komponenten
5
Versuchsvorschrift
A mixture of 1-(3,4-dihydro-2H-chromen-6-yl)ethanone (3.80 g, 22.0 mmol) and sodium hypochlorite [150 mL of a 6.0% aqueous solution, (Clorox brand of bleach)] in a 55° C. oil bath is stirred for 2 h. The mixture (now homogeneous) is cooled to rt and solid sodium bisulfite is added until a clear color persisted. HCl (ca 15 mL of a 6.0 M aqueous solution) is added, followed by extraction with EtOAc. The organic layer is washed with brine, dried (MgSO4), filtered, and concentrated in vacuo to afford 3.10 g (82%) of chromane-6-carboxylic acid as a white solid. 1H NMR (400 MHz, DMSO-d6) δ 12.55, 7.67, 7.6, 6.79, 4.20, 2.77, 1.96-1.90.