Pivalaldehyde → 1-(2,2-Dimethylpropyl)-5-oxoproline

L-glutamic acid (1.47 g, 10 mmol) was dissolved in 2N aqueous sodium hydroxide (10 ml, 20 mmol) and treated with a solution of trimethylacetaldehyde (1.09 ml, 10 mmol) in ethanol (5 ml) and then stirred at room temperature for 30 minutes. The mixture was cooled to 0° C. and treated with sodium borohydride (0.130 g). The mixture was allowed to warm to room temperature with stirring over 4 hrs and then acidified to neutral pH. Concentration in vacuo was followed by slurrying in ethanol and azeotroping three times with more ethanol. Finally the remaining material was suspended in ethanol (50 ml) and heated at reflux for 48 hrs. The mixture was then cooled to room temperature, salts were filtered off and the solvent was evaporated in vacuo to give a gum. Trituration with diethyl ether followed by drying afforded pure solid 1-(2,2-dimethylpropyl)-5-oxoproline (1.1 g).

1. temperatureThe mixture was cooled to 0° C.
2. temperatureto warm to room temperature
3. stirringwith stirring over 4 hrs
4. concentrationConcentration in vacuo
5. customazeotroping three times with more ethanol
6. temperatureheated
7. temperatureat reflux for 48 hrs
8. temperatureThe mixture was then cooled to room temperature
9. filtrationsalts were filtered off
10. customthe solvent was evaporated in vacuo
11. customto give a gum
12. customby drying

ORD record

ord-ef802961ea0f4572b77558fb2c4b47f7

Source dataset

uspto-grants-2011_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08048907B2