HCID 19011685, compound → HCID 19011686, compound

Participants

Reaction Steps

250 ml of a 50% trifluoroacetic acid-methylene chloride solution was added dropwise under ice-cooling to 5.63 g of 2-{1-[(tert-butoxycarbonyl)amino]-1-methylethyl}-5-methyl-4H-3,1-benzoxazin-4-one with stirring. The mixture was stirred at 0° C. for 0.58 hour, and concentration of the mixture gave a residue which was dissolved in 80 ml of a 4N hydrochloric acid-1,4-dioxane solution at 0° C. After stirring for 0.58 hour, the reaction mixture was subjected to azeotropic distilation with toluen so as to give the hydrochloride salt of 2-(1-amino-1-methylethyl)-5-methyl-4H-3,1-benzoxazin-4-one. To the salt was added 4.47 g of 9-fluorenyloxyacetic acid, and dissolved in 180 ml of N,N-dimethylformamide. To the mixture were added successively at room temperature 2.2 ml of N-methylmorpholine, 2.98 g of 1-hydroxybenzotriazole and 5.09 g of a water-soluble carbodiimide hydrochloride. After stirring for 18 hours, the reaction mixture was concentrated to give a residue which was purified by a silica gel column chromatography (eluting solution: methylene chloride-ether), followed by recrystallization from methylene chloride-ether to give 6.34 g of 2-{1-[(9-fluorenyloxyacetyl)amino]-1-methylethyl}-5-methyl-4H-3,1-benzoxazin-4-one: mp 162.1°-162.8° C. (see Table 1).

Provenance & Evidence