Reaction #838943

Reaction equation

phenacyl ester

tert-Butyl (S)-2-{1-[(S)-2-((S)-2-{(2S,4R)-2-[(S)-2-benzyloxycarbonylamino-2-(2-oxo-2-phenylethoxycarbonyl)-ethoxycarbonyl]-4-methyl-pyrrolidin-1-yl}-1-methyl-2-oxo-ethylcarbamoyl)-piperidin-1-yl]-methanoyl}-pyrrolidine-1-carboxylate

→

tert-Butyl (S)-2-[1-((S)-2-{(S)-2-[(2S,4R)-2-((S)-2-benzyloxycarbonylamino-2-carboxy-ethoxycarbonyl)-4-methyl-pyrrolidin-1-yl]-1-methyl-2-oxo-ethylcarbamoyl}-piperidin-1-yl)-methanoyl]-pyrrolidine-1-carboxylate

Solvents

acetic acid

Conditions

Workup

1. 1
   FiltrationThe reaction solution is filtered off through kieselguhr
2. 2
   Washwashed with ethyl acetate
3. 3
   ConcentrationThe organic phase is concentrated in vacuo (not to dryness), the residue
4. 4
   Extractionis extracted
5. 5
   workup.STIRRINGby shaking with ethyl acetate and 1N hydrochloric acid
6. 6
   Otherthe phases are separated
7. 7
   ExtractionThe aqueous phase is extracted with ethyl acetate
8. 8
   Dryingthe combined organic phases are dried over sodium sulfate
9. 9
   Filtrationfiltered
10. 10
    Concentrationconcentrated to dryness
11. 11
    Otherevaporated in vacuo
12. 12
    Extractionextracted
13. 13
    workup.STIRRINGby shaking with saturated aqueous sodium hydrogencarbonate solution
14. 14
    Washthe aqueous phase is washed again with diethyl ether
15. 15
    Extractionextracted twice with ethyl acetate
16. 16
    DryingThe combined organic extracts are dried over sodium sulfate
17. 17
    Filtrationfiltered
18. 18
    Otherthe solvent is removed in vacuo
19. 19
    Other4.01 g (91% of th.) of the product are obtained as a hard foam

Procedure

5.17 g (6.1 mmol) of the phenacyl ester from example 24A are dissolved in 90 pc. aqueous acetic acid (60 ml) and treated with 2.99 g (45.8 mmol) of zinc powder. The reaction mixture is stirred at RT for 2 h. The reaction solution is filtered off through kieselguhr and washed with ethyl acetate. The organic phase is concentrated in vacuo (not to dryness), the residue is extracted by shaking with ethyl acetate and 1N hydrochloric acid, and the phases are separated. The aqueous phase is extracted with ethyl acetate, and the combined organic phases are dried over sodium sulfate, filtered and concentrated to dryness. The residue is taken up twice in toluene and evaporated in vacuo. The residue is taken up in diethyl ether, extracted by shaking with saturated aqueous sodium hydrogencarbonate solution and the aqueous phase is washed again with diethyl ether. The aqueous phase is subsequently adjusted to pH 2.7 using 5N hydrochloric acid and extracted twice with ethyl acetate. The combined organic extracts are dried over sodium sulfate, filtered and the solvent is removed in vacuo. 4.01 g (91% of th.) of the product are obtained as a hard foam.

Source