[OH-].[Na+].[ClH:3].[O:4]1[C:13]2[C:8](=[CH:9][CH:10]=[CH:11][CH:12]=2)[CH2:7][CH:6]([CH2:14][CH2:15][NH:16][CH2:17][CH2:18][C:19]([O:21]C)=[O:20])[CH2:5]1.O>CO>[ClH:3].[O:4]1[C:13]2[C:8](=[CH:9][CH:10]=[CH:11][CH:12]=2)[CH2:7][CH:6]([CH2:14][CH2:15][NH:16][CH2:17][CH2:18][C:19]([OH:21])=[O:20])[CH2:5]121 ml (42 mmol) of 2N sodium hydroxide solution are added at room temperature while stirring to a solution of 2.99 g (10 mmol) of N-[2-(chroman-3-yl)ethyl]-N-(2-methoxycarbonylethyl)-amine hydrochloride in 60 ml of methanol. After 5 minutes, 40 ml of water are added to the reaction mixture which is then stirred for 30 minutes at 50°-60°. After cooling, the mixture is concentrated by evaporation in vacuo. The residue is dissolved in 30 ml of water, and then 10 ml of hydrochloric acid (36% strength) are added and the whole is cooled in an ice bath. The crystals formed are filtered off with suction. 2.5 g (87.5%) of N-[2-(chroman-3-yl)ethyl]-N-(2-carboxyethyl)-amine hydrochloride are obtained (m.p. 186°-188°).
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