1,2-Dichloroethane → Propionic anhydride

A representative procedure was as follows: A solution of propionic anhydride was prepared in situ by reacting propionic acid (0.48 g, 6.5 mmol) with EDC (614 mg, 3.2 mmol) in acetonitrile for 15 min at room temperature. This solution was then added over the course of 5 min to a magnetically stirred solution of N-ε-benzyloxycarbonyl lysine (Lys(Cbz)) (1 g, 3.6 mmol) in 36 mL 0.1 M NaOH and 20 mL 2-propanol. A fine white precipitate formed, another 36 mL 0.1 M NaOH was added, and stirring was continued overnight. The reaction mixture was then concentrated in vacuo to remove the organic solvents and acidified to a pH of 2.5 with 1M HCl. During acidification, the white precipitate dissolved. The aqueous solution was extracted with chloroform and then ethyl acetate. These organic solvents were combined and concentrated on the rotary evaporator to yield a colorless oil which was used without purification in the next step.

1. customfor 15 min
2. customat room temperature
3. customA fine white precipitate formed
4. concentrationThe reaction mixture was then concentrated in vacuo
5. customto remove the organic solvents
6. dissolutionDuring acidification, the white precipitate dissolved
7. extractionThe aqueous solution was extracted with chloroform
8. concentrationconcentrated on the rotary evaporator
9. customto yield a colorless oil which
10. customwas used without purification in the next step

ORD record

ord-1a77eccad4ef49c8b19a77974d563b92

Source dataset

uspto-grants-2010_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07718782B2