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

Participants

Reaction Conditions

Reaction Steps

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).

Provenance & Evidence