Ethanol → 1,1-dimethylethyl (3S)-3-(2-hydrazino-2-oxoethyl)-1-pyrrolidinecarboxylate

A solution of ((3S)-1-{[(1,1-dimethylethyl)oxy]carbonyl}-3-pyrrolidinyl)acetic acid (5 g, 21.81 mmol) in diethyl ether (50 mL) was treated with N,N-dimethyl-4-pyridinamine (2.181 mmol), N-[3-(dimethylamino)propyl]-N′-ethylcarbodiimide(HCl) (23.99 mmol), and ethanol (48.0 mmol) and was stirred at room temperature overnight. Analysis by LCMS indicated that all starting material had converted to the desired methyl ester. The reaction contents were diluted with ether (100 mL) and washed with saturated aq NaHSO4 solution, water, and brine. The organic phase was dried over magnesium sulfate, filtered and concentrated to dryness in vacuo. The resulting clear oil was dissolved in ethanol (25 mL), treated with hydrazine monohydrate (436 mmol), and was stirred overnight at 80° C. LCMS analysis indicated complete conversion of the intermediate. The reaction solution was concentrated to dryness in vacuo to afford the title compound as a clear oil (4.65 grams, 88% yield). No further purification was utilized. MS(ES)+ m/e 244.2 [M+H]+.

1. customThe reaction contents
2. washwashed with saturated aq NaHSO4 solution, water, and brine
3. dry with materialThe organic phase was dried over magnesium sulfate
4. filtrationfiltered
5. concentrationconcentrated to dryness in vacuo
6. dissolutionThe resulting clear oil was dissolved in ethanol (25 mL)
7. stirringwas stirred overnight at 80° C
8. concentrationThe reaction solution was concentrated to dryness in vacuo

ORD record

ord-de1b76f89a384877a091e2a2440b0c93

Source dataset

uspto-grants-2014_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08802864B2