Methanol → Benzyl 4-(2-hydroxyethyl)piperazine-1-carboxylate

Temperature

0 °C

A 250 mL round bottomed flask was charged with N-(2-hydroxyethyl)piperazine (3.00 g, 24.4 mmol) followed by anhydrous THF (150 mL) and triethylamine (3.40 mL, 24.4 mmol). The resulting solution was cooled to 0° C. and a solution of benzyl chloroformate (3.10 mL, 21.8 mmol) in anhydrous THF (10 mL) was slowly added via syringe resulting in the formation of a cloudy white suspension. This suspension was stirred at 0° C. for 30 minutes, then allowed to warm to room temperature with stirring over 3 h. The reaction mixture was then concentrated under reduced pressure. Purification of the residue by silica gel chromatography, eluting with 5% MeOH in CH2Cl2, afforded 5.76 g (100%) of Preparation 2 as a colorless oil. Rf=0.60 (SiO2, 5% MeOH in CH2Cl2). 1H NMR (500 MHz, CDCl3): δ=7.34 (m, 5H), 5.13 (s, 2H), 3.62 (t, J=5.2 Hz, 2H), 3.52 (t, J=5.2 Hz, 4H), 2.64 (br s, 1H), 2.55 (t, J=5.2 Hz, 2H) and 2.47 (br s, 4H). m/z=265 [M+H]+.

1. customresulting in the formation of a cloudy white suspension
2. temperatureto warm to room temperature
3. stirringwith stirring over 3 h
4. concentrationThe reaction mixture was then concentrated under reduced pressure
5. customPurification of the residue by silica gel chromatography
6. washeluting with 5% MeOH in CH2Cl2
7. customafforded

ORD record

ord-b03265b2936e41d583a357ad56881062

Source dataset

uspto-grants-2009_06

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07550458B2