1,3-Propanediamine, N'-(ethylcarbonimidoyl)-N,N-dimethyl-, monohydrochloride → [4-(4-Benzyloxycarbonylaminobutyl)phenoxy]acetic acid 2-tert-butoxycarbonylamino-ethyl ester

Participants

Reaction Steps

[4-(4-Benzyloxycarbonylaminobutyl)phenoxy]acetic acid 48 (240 mg, 0.67 mmol) was dissolved in anhydrous CH2Cl2 (6 mL). To the solution was added DMAP (98 mg, 0.80 mmol), followed by EDC-HCl (154 mg, 0.81 mmol). The reaction mixture was stirred at room temperature for 15 min. (2-Hydroxyethyl)carbamic acid tert-butyl ester (0.21 mL, 1.34 mmol) was then added and the stirring was continued for 16 h. Solvent was removed by rotary evaporation. The residue was subjected to flash silica gel column chromatography eluting with ethyl acetate/dichloromethane (1:20, 1:15, and 1:10, v/v) to give the desired ester 44a as a colorless oil (162 mg, 48% yield). 1H NMR (300 MHz, CDCl3) δ 1.35-1.65 (m, 4H), 1.44 (s, 9H), 2.45-2.58 (m, 2H), 3.10-3.22 (m, 2H), 3.25-3.42 (m, 2H), 4.18-4.28 (m, 2H), 4.62 (s, 2H), 4.70 (br s, 1H), 4.84 (br s, 1H), 5.08 (s, 2H), 6.81 (d, 2H), 7.07 (d, 2H), 7.25-7.38 (m, 5H). m/z (ESI) 501 [C27H36N2O7+H]+.

Provenance & Evidence