Example 112: Synthesis of 1,3-oxazole-2-carbonitrile; 1,3-oxazole-2-carboxamide (0.98 g, 8.8 mmol, 1.0 eq.) was dissolved in pyridine (17 mL), followed by the addition of phosphorus triclosan (1.2 mL, 12.2 mmol, 1.4 eq.). The reaction mixture was stirred at room temperature for 5 h. The solution was observed to change from a beige slurry to a brown color. After completion of the reaction, the mixture was diluted with ice water and extracted with ether. The aqueous layer was adjusted to pH 3 with 6 M hydrochloric acid and extracted again with ether. The combined ether extracts were washed sequentially with water and saturated brine, dried over anhydrous magnesium sulfate, filtered and concentrated under reduced pressure to give 1,3-oxazole-2-carbonitrile as an amber colored oil (0.61 g, 74% yield). The product was characterized by 1H NMR (400 MHz, DMSO-d6): δ 8.608 (s, 1H), 7.67 (s, 1H).
