Water → (2S,4R)-N-t-Butoxycarbonyl-4-methyl glutamic acid

A solution of (3R,5S)-1-t-Butoxycarbonyl-5-carboxy-3-methylpyrrolidine-2-one (6.2 g, 25.5 mmol) in THF (50 mL) was treated with lithium hydroxide monohydrate (3 eq, 3.20 g) and water (5 mL). After stirring for 16 hr at room temperature the THF was removed in vacuo and water (20 mL) was added. The pH was adjusted to 3 by the addition of glacial acetic acid, ether (100 mL) was added and the layers separated. The aqueous phase was extracted with ether (3 x 100 mL) and the combined organic phases were washed with brine (400 mL), dried over Na2SO4, filtered and evaporated to dryness, azeotroping with toluene (3 x 15 mL). The residue was dried under high vacuum to give 6.58 g of the product (99%) as a white foam which was used without further purification: Rf 0.8 (1% formic acid in ethyl acetate, developed with ninhydrin). 1H NMR (200 MHz, D2O): δ 3.80 (dd, J=10.4, 4.7 Hz, 1H), 2.45 (m, 1H), 2.0 (m, 1H), 1.60 (ddd, J=12.8, 4.2, 10.3 Hz, 1H), 1.25 (s, 9H), 1.0 (d, J=7.0 Hz, 3H).

1. customwas removed in vacuo and water (20 mL)
2. additionwas added
3. additionThe pH was adjusted to 3 by the addition of glacial acetic acid, ether (100 mL)
4. additionwas added
5. customthe layers separated
6. extractionThe aqueous phase was extracted with ether (3 x 100 mL)
7. washthe combined organic phases were washed with brine (400 mL)
8. dry with materialdried over Na2SO4
9. filtrationfiltered
10. customevaporated to dryness
11. customazeotroping with toluene (3 x 15 mL)
12. customThe residue was dried under high vacuum

ORD record

ord-739eba69493e45fba73186e7ab16d952

Source dataset

uspto-grants-1998_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05731348