Acetic Anhydride → HCID 59880457, compound

Participants

Reaction Steps

That is, 10 mg of the (4R)-1,4-dihydro-2,6-dimethyl3-(2-aminoethyl) oxycarbonyl-4-(3-nitrophenyl)pyridine-5-carboxylic acid obtained in Example 28 was dissolved in 2 ml of deionized water and 0.2 ml of acetic anhydride was added to the solution while stirring at room temperature. After stirring for continuous 30 minutes, the reaction mixture was extracted 3 times with 5 ml each of ethyl acetate and washed with 10 ml of saturated saline. The ethyl acetate layer was adsorbed on a preparatory TLC plate, developed with chloroform/methanol (7:1) to elute fractions showing UV absorption at Rf 0.22. The eluate was evaporated to dryness to obtain 3.7 mg of (4R)-3-(2-acetamidoethyl) oxycarbonyl-1,4-dihydro-2,6-dimethyl-4-(3-nitrophenyl) pyridine-5-carboxylic acid. The optical purity of this substance was determined by HPLC(mobile phase: 0.35% isopropanol/0.1M phosphaste buffer solution (pH 4.4), flow rate: 0.8 ml/minute) using an otical resolution column: CHIRAL AGP (4 mm×100 mm) manufactured by Daicel Chemical Industries Ltd. As a result, it revealed that the optical purity of the 4R form was 100% and the retention time was 14.3 minutes.

Provenance & Evidence