Ethylenediamine → Benzyl N-(2-aminoethyl)carbamate

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Reaction Steps

Ethylenediamine (1.0 g, 16.7 mmol) is dissolved in water (3.0 mL) containing bromocresol green as an indicator. Methane sulfonic acid (2.8 g, 31 mmol) in water (3.0 mL) is added until a blue to pale yellow color transition is just achieved. The solution is diluted with ethanol (8.0 mL) and vigorously stirred. To the mixture was added the solution of Cbz-Cl (2.8 g, 16.7 mmol) in dimethoxyethane (4 mL) and 50% w/v aqueous AcOK (10 mL) at 20° C. simultaneously to maintain the pale yellow-green color of the indicator. After the additions are complete the mixture was stirred (RT, 1 h) and concentrated at low temperature under vacuum to removed the volatiles. The residue was shaken with water (20 mL) and filtered. The filtrate was then washed with toluene (3×50 mL), basified with excess 40% aqueous NaOH and extracted with toluene (3×50 mL). The organic layer was washed with brine (50 mL), dried over Na2SO4 and evaporated to give benzyl 2-aminoethylcarbamate as an oil (1.65 g, 51%). Mass calculated for C10H14N2O2=194.23; found: [M−H]+=193.3.

Provenance & Evidence