4-Methylmorpholine → 1-Methylethyl N-[(1R)-1-[[[(1R)-1-(6-fluoro-2-benzothiazolyl)ethyl]amino]carbonyl]-2-methylpropyl]carbamate

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Reaction Steps

In 500 ml of toluene, 10.2 g (0.05 mol) of N-isopropoxycarbonyl-D-valine was dissolved. Thereto were dropwise added, at −5° C., 12.4 g (0.0125 mol) of N-methylmorpholine and 6.8 g (0.05 mol) of isobutyl chlorocarbonate. Thereto was added, at −5° C., 18.3 g (0.05 mol) of (R)-1-(6-fluoro-2-benzothiazolyl)ethylamine p-toluenesulfonate. A reaction and a post-treatment were conducted in the same manner as in Reference Example 1, and the suspension of a solid in toluene was filtered to collect the solid. The solid was subjected to Soxhlet extraction for 1 week, and the extract was concentrated to obtain a solid. The solid was recrystallized from xylene to obtain 11.6 g (yield: 62.7%) of isopropyl {(R)-1-[(R)-1-(6-fluorobenzothiazol-2-yl)ethylcarbamoyl]-2-methylpropyl}carbamate. The compound obtained was confirmed for the structure by IR analysis and NMR analysis in comparison with its authentic material and identified.

Provenance & Evidence