反应详情

温度

60 °C

First, 320 g (1.983 mol) of L-glutamic acid-γ-methyl ester was suspended in 500 g of methanol. To this, 219 g (2.186 mol, 1.1 eq.) of acetylacetone and 200 g (1.983 mol, 1 eq.) of triethylamine were added. The mixture was stirred at 60° C. for one hour. Subsequently, 1,277 g (19.8 mol) of 70% ethylamine was added to the mixture. After the mixture was allowed to react for 6 hours, the reaction solution was heated under normal pressure. In this manner, 667 g of excessive ethylamine was recovered and deprotection was performed at the same time. To the slurry of the theanine precipitated, 1 L of 2-propanol was added. The crystal was filtrated by suction and washed with 200 mL of 99.5% ethanol to obtain theanine (314.3 g) as a white crystal substance (yield: 91%). The obtained theanine had the same purity as high as in Example 1.

1. customto react for 6 hours
2. temperaturethe reaction solution was heated under normal pressure
3. customIn this manner, 667 g of excessive ethylamine was recovered
4. customTo the slurry of the theanine precipitated
5. addition1 L of 2-propanol was added
6. filtrationThe crystal was filtrated by suction
7. washwashed with 200 mL of 99.5% ethanol