62247-21-6

500-22-1

62247-21-6

Example 18 Synthesis of 3-amino-3-(3'-pyridinyl)propionic acid: ammonium acetate (194.28 g, 2.52 mol) was suspended in ethanol (285 g). A solution of pyridine-3-carboxaldehyde (62.9 g, 1.68 mol) in ethanol (80 g) was added dropwise to the suspension over a period of 10 min at 15°C to 20°C. The reaction was carried out by stirring the mixture for 1 h until the reaction was completed. The reaction mixture was stirred for 1 hour until a pale yellow clarified solution was formed. Subsequently, an ethanol (235 g) suspension of malonic acid (174.86 g, 1.68 mol) was added over 30 minutes. After stirring at room temperature for 30 min, the reaction mixture was heated to reflux (78°C) and maintained for 5 hours. Gas release was observed during the reaction. after 3 to 4 hours, a white solid began to precipitate. The orange suspension was cooled to 15°C to 20°C to form a thick slurry. Methanol (80 g) was added to the slurry and the reaction mixture was heated to reflux (65°C) again. The suspension was thermally filtered and the filter cake was washed with three parts of hot methanol (120 g, 55°C to 65°C). The wet product was dried under vacuum at 70°C to 80°C to give a colorless solid product (137.73 g, 49.3% yield). the LC purity was 95.8%.