Methanol → 919101-41-0

Temperature

-78 °C

To a flame dried Schlenk tube equipped with a magnetic stirring bar, a rubber septum and a N2 inlet was added aziridine-2-carboxylic acid methyl ester 1d (1.01 g, 10 mmol) dissolved into 25 ml of anhydrous toluene. The reaction flask was cooled to −78° C., at which point 13 ml of a 1.5M solution of DIBAL in toluene was added slowly via syringe to the reaction mixture over a period of 30 minutes. The reaction was allowed to stir for 5 hours or until completed by TLC. MeOH was added via syringe to the reaction mixture over a period of 15 minutes while maintaining a temperature of −78° C. After the addition of MeOH, the reaction mixture was allowed to warm to room temperature and stir for 30 minutes. A few drops of saturated aqueous Na2SO4 were used to cause precipitation of aluminum salts, which were filtered off after stirring for another 30 minutes. The filtrate was concentrated under reduced pressure to yield a thick clear oil, which was pure enough by NMR to use in subsequent transformations. An analytically pure sample can be obtained by subjecting the crude product to flash column chromatography (silica gel; 20% water in MeCN, Rf=0.32) to yield the title compound as a colourless oil in 76% yield. The compound is water soluble. 1H NMR (CDCl3 with D2O present, 400 MHz) δ: 5.33 (s, 0.5H), 5.27 (s, 1H), 4.92 (s, 1H), 4.91 (s, 0.5H), 2.62 (dd, J=5.2 Hz, 3.2 Hz, 1H), 2.53 (dd, J=5.6 Hz, 3.6 Hz, 0.5H), 2.47-2.43 (m, 1H), 2.39 (quintet, J=3.2 Hz, 0.5H), 2.29 (d, J=3.6 Hz, 0.5H), 2.10 (d, J=6.4 Hz, 0.5H), 1.86 (d, J=6.4 Hz, 1H), 1.76 (d, J=5.2 Hz, 1H), 1.70 (dd, J=5.2 Hz, 3.6 Hz, 1.5H), 1.26 (d, J=3.2 Hz, 1H), 1.21 (d, J=3.2 Hz, 0.5H) ppm. 13C NMR (CDCl3, 100 MHz) δ: 96.6 (major), 95.7 (minor), 95.6 (minor), 94.8 (major), 44.8 (minor), 44.0 (major), 31.9 (minor), 31.6 (major), 28.0 (major), 27.6 (minor), 21.3 ppm.

1. customTo a flame dried Schlenk tube
2. customequipped with a magnetic stirring bar
3. additionwas added slowly via syringe to the reaction mixture over a period of 30 minutes
4. temperaturewhile maintaining a temperature of −78° C
5. temperatureto warm to room temperature
6. stirringstir for 30 minutes
7. customprecipitation of aluminum salts, which
8. filtrationwere filtered off
9. stirringafter stirring for another 30 minutes
10. concentrationThe filtrate was concentrated under reduced pressure
11. customto yield a thick clear oil, which
12. customAn analytically pure sample can be obtained

ORD record

ord-49ca1b8c67dc4329ba0b4cb0842a05b7

Source dataset

uspto-grants-2012_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08143375B2