An efficient synthesis of Vildagliptin intermediates

Efficient and high yielding methods for the preparation of vildagliptin 1 intermediate of (S)-1-(2-chloroacetyl) pyrrolidine-2-carbonitrile 2 and 3-amino-1-adamantane alcohol 3 respectively have been described. (S)-1-(2-Chloroacetyl) pyrrolidine-2-carbonitrile 2 has been synthesized from L-proline 2a via chloroacetyl chloride, performed with acetonitrile in the presence of sulfuric acid via one-pot reactions. 3-Amino-1-adamantane alcohol 3 has been prepared from amantadine hydrochloride via oxidation by sulfuric acid/nitric acid and boric acid as catalyst, and has been subjected to ethanol extraction. The overall yield is about 95%.