Sodium Carbonate → Methyl (5-methyl-2-phenyl-1,3-oxazol-4-yl)acetate

Participants

Reaction Steps

To β-methyl N-benzoyl-L-aspartate (compound [3]; 229.9 g) obtained in Example 1 were successively added toluene (1.2 L), acetic anhydride (346 mL), N-methylmorpholine (4.7 mL) and 4-dimethylaminopyridine (1.04 g) and the mixture was stirred at internal temperature of 55–0° C. for 4 hr to give a solution of methyl 3-benzoylamino-4-oxopentanoate (compound [4]) in toluene. Without isolating compound [4], p-toluenesulfonic acid monohydrate (31.8 g) was added to this solution of methyl 3-benzoylamino-4-oxopentanoate (compound [4]) in toluene. The mixture was stirred at 85–90° C. for 5 hr and cooled to room temperature. To the reaction mixture was added, with stirring, an aqueous solution of sodium carbonate (75.6 g) in water (303 mL), and the mixture was adjusted to pH 7–7.5. After standing still, the aqueous layer was removed and the organic layer was concentrated to give the title compound (compound [5]; 206.7 g, yield 97.7%).

Provenance & Evidence