Aminoisobutyric acid → N-((Benzyloxy)carbonyl)-2-methylalanine

To a solution of 2-amino-2-methyl-propanoic acid (10 g, 96.97 mmol) in water (75 mL) was added triethylamine (13.48 mL, 96.97 mmol) followed by the dropwise addition of a solution of benzyl (2,5-dioxopyrrolidin-1-yl) carbonate (24.17 g, 96.97 mmol) in MeCN (30 mL). The pH was monitored during the addition and afterwards was adjusted with triethylamine (1.5 mL) from pH 7 to 8. The mixture was stirred at room temperature overnight. The reaction mixture was concentrated by removal of MeCN. To the aqueous was added saturated aqueous sodium bicarbonate (2 mL) which gave a suspension. This was filtered and the solid kept to one side. The filtrate was extracted with ether (three times). The aqueous phase was acidified to pH 3 with approximately 1 M aqueous potassium bisulphate and then extracted into EtOAc (three times). The combined EtOAc extracts were dried over magnesium sulphate, filtered and evaporated to yield 2-(benzyloxycarbonylamino)-2-methyl-propanoic acid (D32) as a waxy white solid, (18.001 g);

1. additionThe pH was monitored during the addition
2. concentrationThe reaction mixture was concentrated by removal of MeCN
3. additionTo the aqueous was added saturated aqueous sodium bicarbonate (2 mL) which
4. customgave a suspension
5. filtrationThis was filtered
6. extractionThe filtrate was extracted with ether (three times)
7. extractionextracted into EtOAc (three times)
8. dry with materialThe combined EtOAc extracts were dried over magnesium sulphate
9. filtrationfiltered
10. customevaporated

ORD record

ord-d364bc87830b4a58b79c93b0eae4f71f

Source dataset

uspto-grants-2016_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09309254B2