Hydrochloric Acid → 2H-chromen-6-ol

HRID 1835487Notes

Reaction equation

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

Participants

Conditions

Temperature: 60 °C

Procedure

A solution of the chromene acetate (1.0 g, 2.13 mmol) in ethanol (20 mL) was treated with 2 N NaOH (20 mL) and stirred at 60° C. for 90 min. The reaction mixture was cooled, acidified with 5 N HCl, and the ethanol was removed in vacuo. The resulting aqueous solution was extracted with ether and concentrated to a light yellow oil that was purified by silica gel chromatography eluting with ethyl acetate (15%, v/v) in hexanes. This yielded the desired chromene-6-ol intermediate as a colorless oil (0.92 g, 98%). 1H-NMR (CDCl3/TMS, ppm): 0.87 (m, 12H, 4a′-, 8a′-, 12a′-, 13′-CH3), 1.0-1.6 (m, 24H, 4′-, 8′-, 12′-CH, 1′-,2′-,3′-,5′-,6′-, 7′-,9′-,10′-,11′-CH2, 2a-CH3), 2.14, 2.18, 2.19 (3×s, 9H, 5a-, 7a-, 8a-CH3), 5.63, 6.55 (2×d, J=10.0 Hz, 2H, CH); 13C-NMR (CDCl3, ppm): 10.8, 11.6, 12.4 (5a-, .7a-, 8a-CH3), 19.6, 19.7 (CH3), 21.3 (CH2), 22.6, 22.7 (CH3), 24.4, 24.8 (CH2), 25.2 (2a-CH3), 27.9 (CH), 30.9 (3-CH2), 32.7, 32.8 (CH), 37.2, 37.4, 37.5, 39.3, 40.5 (CH2), 50.8 (2-C), 116.2, 117.8, 120.1, 122.3, 123.0, 130.0 (aryl and vinyl C), 144.6, 145.3 (aryl C—O), 169.4 (CO); HRMS (CI, m/z): 428.365275 M+H+, Calc. for C29H48O2 428.365431.

Workup

temperatureThe reaction mixture was cooled
customthe ethanol was removed in vacuo
extractionThe resulting aqueous solution was extracted with ether
concentrationconcentrated to a light yellow oil that
customwas purified by silica gel chromatography
washeluting with ethyl acetate (15%, v/v) in hexanes

Sources & evidence

ORD record: ord-14e65de41e59443f937c272ae32b2f2b
Source dataset: uspto-grants-2004_08
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US06770672B1

Reaction notes

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