Pyruvic Acid → 2,2-Diethoxypropionic acid

Reaction equation

[C:1]([OH:6])(=[O:5])C(C)=O.C(O[CH:10]([O:14][CH2:15][CH3:16])[O:11][CH2:12][CH3:13])C.S(=O)(=O)(O)O.Cl[CH2:23]Cl>>[CH2:15]([O:14][C:10]([O:11][CH2:12][CH3:13])([CH3:23])[C:1]([OH:6])=[O:5])[CH3:16]

Participants

Reactant 4

HCID 1060Pyruvic Acid

HCID 1118Sulfuric Acid

HCID 6344Dichloromethane

HCID 31214Ethyl orthoformate

Product 1

HCID 137023972,2-Diethoxypropionic acid

Conditions

Temperature: 7.5 °C

Procedure

To a stirred solution of pyruvic acid (14 mL, 0.2 mol) and triethylorthoformate (80 mL) at 10° C. was added concentrated sulfuric acid (1 mL). The resulting mixture was stirred at 5-10° C. for 1 h and then diluted with dichloromethane (200 mL). The organic solution was washed successively with water (3×80 mL) and saturated sodium chloride solution (80 mL) and then dried over anhydrous sodium sulfate. The mixture was filtered and then concentrated to give a quantitative yield of 2,2-diethoxypropionic acid as an oil. 1H NMR (CDCl3, 400 MHz): δ 1.30 (t, 6H), 1.61 (s, 3H), 3.57 (q, 4H), 8.62 (s, 1H). The acid form was quantitatively converted to its cesium salt (25) by dissolving the acid in water (25 mL) followed by treatment with an equimolar quantity of cesium carbonate, and then lyophilization. 1H NMR (D2O, 400 MHz): δ 0.98 (t, 6H), 1.28 (s, 3H), 3.22 (q, 2H), 3.47 (q, 2H).