TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Process: The step (a) is carried out in presence of a base, such as potassium carbonate. The step (b) is carried out in presence of a dehydrating agent consisting of phosphoryl chloride, Vilsmeier reagent, Gold reagent, mixture of dimethylformamide and triphosgene, mixture of dimethylformamide and thionyl chloride, and mixture of dimethylformamide and oxalyl chloride. The step (b) is carried out at 0-20 degrees C. (III) and/or (IV) is isolated from the reaction mixture by slurring the reaction mixture with an organic solvent. The step (c) is carried out at 40-80 degrees C. Preferred Components: The nitrile solvent in step (a) is acetonitrile. The organic solvent is ether solvent, and/or alcohol solvent. (I) has impurities (such as 1-(2-chloro-acetyl)-pyrrolidine-2-carboxylic acid and 1-(2-(2-carbamoylpyrrolidin-1-yl)-2-oxo-ethyl)pyrrolidine-2-carboxamide) of less than 0.15 wt.% as determined by HPLC. ACTIVITY - Antidiabetic.    MECHANISM OF ACTION - Dipeptidyl peptidase IV (DPP-IV) inhibitor.    EXAMPLE - 100 g of 1-Amino-3-adamantol in 1000 ml of acetonitrile was charged in a clean round bottom flask. 239.8g of Potassium carbonate was charged to the flask. The reaction mass was heated to 82-85 degrees C. (S)-1-(2-Chloroacetyl)pyrrolidine-2-carbonitrile was charged after 60-90 minutes intervals. After completion of reaction, the reaction mass was cooled to 65-70 degrees C. The reaction mass was filtered and the solid was washed with 500 ml of acetonitrile and suck dried. The acetonitrile was distilled out from filtrate under vacuum at 50-55 degrees C. Ethyl acetate was charged to the residue and the slurry stirred at 50-55 degrees C for 30-45 minutes. The slurry was cooled to 20-30 degrees C and stirred for 60-90 minutes. The solid was filtered and washed with ethyl acetate and suck dried. The wet cake was suspended in isopropyl alcohol and heated to 80-85 degrees C to get a clear solution. The clear solution was charcoalized and filtered. The filtrate was distilled out under vacuum, and the reaction mass was cooled to -5 to 5 degrees C and stirred for 60-90 minutes. The solid was filtered and washed with isopropyl alcohol and suck dried. The solid was dried under vacuum at 50-55 degrees C to afford 105-120 g of vildagliptin.