1-Chloroethyl chloroformate → 4-[4-(4,5-Dihydro-5-phenyl-3-isoxazolyl)-2-thiazolyl]-1,2,3,6-tetrahydropyridine hydrochloride

To a solution of 4-[4-(4,5-dihydro-5-phenyl-3-isoxazolyl)-2-thiazolyl]-1,2,3,6-tetrahydro-1-(phenylmethyl)pyridine (i.e. the product of Example 13, Step B) (0.400 g, 0.99 mmol) in dichloroethane (10 mL) was added 1-chloroethyl chloroformate (0.286 g, 1.99 mmol), and the reaction mixture was heated to 80° C. for 5 h. The reaction mixture was cooled to room temperature and concentrated under reduced pressure. Methanol (10 mL) was added to the residue, and the resulting mixture was heated to 60° C. for 1 h, cooled to room temperature, and concentrated under reduced pressure. The residue was triturated with 50% of petroleum ether in ethyl acetate, and the solid formed was filtered and dried to give 0.25 g of the title compound as a white solid.