Hydrochloric Acid → 6-[2-(Ethoxycarbonyl)ethyl]chromane-2-carboxylic acid

HRID 1007767Notes

Reaction equation

[CH3:1][O:2][C:3](/[CH:5]=[CH:6]/[C:7]1[CH:8]=[C:9]2[C:14](=[CH:15][CH:16]=1)[O:13][CH:12]([C:17]([OH:19])=[O:18])[CH2:11][CH2:10]2)=[O:4].[BH4-].[Na+].O.Cl.[CH3:24]O>[Cu]Cl>[CH2:1]([O:2][C:3]([CH2:5][CH2:6][C:7]1[CH:8]=[C:9]2[C:14](=[CH:15][CH:16]=1)[O:13][CH:12]([C:17]([OH:19])=[O:18])[CH2:11][CH2:10]2)=[O:4])[CH3:24]

Participants

Conditions

Temperature: 0 °C

Procedure

In a round bottom flask the compound from Example 31 (0.455 g, 1.74 mmol) was stirred in anhydrous methanol (10 mL) under an argon atmosphere. Copper (I) chloride (0.26 g, 2.6 mmol) was added and the mixture was cooled to 0° C. Sodium borohydride (0.457 g, 17.4 mmol) was added in four portions over 40 minutes. Gas evolution was observed with each addition. The resulting black mixture was stirred for 15 min and then poured into 100 mL water. The aqueous mixture was made acidic by addition of 1.0 N aqueous HCl and extracted with ethyl acetate (3×). The combined organic layers were dried (MgSO4), filtered through celite, and concentrated to a white solid (0.412 g, 90%). 1H NMR (300 MHz, acetone-d6) δ 11.18 (s, 1H), 6.90 (m, 2H), 6.72 (m, 1H), 4.74 (m, 1H), 3.57 (s, 3H), 2.77 (m, 4H), 2.55 (m, 2H), 2.17 (m, 2H).

Workup

additionGas evolution was observed with each addition
extractionextracted with ethyl acetate (3×)
dry with materialThe combined organic layers were dried (MgSO4)
filtrationfiltered through celite
concentrationconcentrated to a white solid (0.412 g, 90%)

Sources & evidence

ORD record: ord-865494e382d048bc82f926be0c7c9b71
Source dataset: uspto-grants-2004_09
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US06797714B2

Reaction notes

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