Sodium borohydride → N-[(1R)-2-hydroxy-1-(3-thienylmethyl)ethyl]acetamide

Participants

Reaction Steps

A solution of 2.15 g of ethyl (2R)-2-(acetylamino)-3-(3-thienyl)propanoate in 24 cm3 of ethanol, stirred under an inert atmosphere, is brought to a temperature of 20° C. 0.5 g of sodium borohydride is added and the reaction medium, which is slightly brown, is stirred for 24 hours at room temperature. A further 0.2 g of sodium borohydride is added and stirring is continued for 24 hours. After evaporation of the reaction mixture under reduced pressure (2 kPa) at a temperature in the region of 40° C., a solid residue is obtained, which is taken up in 30 cm3 of water. This mixture is extracted with twice 100 cm3 of ethyl acetate and the organic phase is then dried over magnesium sulfate and evaporated under reduced pressure (2 kPa) at a temperature in the region of 40° C. to give an off-white solid which is dried in an oven under vacuum (10 Pa) at a temperature in the region of 48° C. 1.4 g of N-[(1R)-2-hydroxy-1-(3-thienylmethyl)ethyl]acetamide are obtained in the form of an off-white solid melting at about 105° C. to become pasty. 1H NMR spectrum (400 MHz, (CD3)2SO-d6, δ in ppm): 1.78 (s: 3H); 2.64 (dd, J=14 and 8 Hz: 1H); 2.87 (dd, J=14 and 5.5 Hz: 1H); from 3.20 to 3.40 (mt: 2H); 3.90 (mt: 1H); 4.76 (t, J=5.5 Hz: 1H); 6.99 (dd, J=5 and 1 Hz: 1H); 7.16 (dd, J=3 and 1 Hz: 1H); 7.43 (dd, J=5 and 3 Hz: 1H); 7.70 (d, J=8.5 Hz: 1H).

Provenance & Evidence