Reaction #50799

Reaction equation

N-[2-(1,3-dihydro-1,3-dioxo-2H-isoindol-2-yl)-1-oxo-3-phenylpropyl]-O-2-propenyl-L-serine, methyl ester

methylene chloride methanol

methylsulfide

→

N-[2-(1,3-dihydro-1,3-dioxo-2H-isoindol-2-yl)-1-oxo-3-phenylpropyl]-O-2-oxoethyl-L-serine, methyl ester

Conditions

Workup

1. 1
   Othersparge with a mixture of ozone/oxygen for approximately 10 minutes until a blue color persists
2. 2
   OtherSparge with nitrogen for 10 minutes at -78° C.
3. 3
   Otherto remove excess ozone
4. 4
   Temperatureto warm to room temperature
5. 5
   Otherevaporate the solvent in vacuo
6. 6
   workup.DISSOLUTIONdissolve the residue in ethyl acetate (200 mL)
7. 7
   WashWash with water, saturated sodium chloride
8. 8
   Dryingdry (Mg SO4)
9. 9
   Otherevaporate the solvent in vacuo

Procedure

Dissolve N-[2-(1,3-dihydro-1,3-dioxo-2H-isoindol-2-yl)-1-oxo-3-phenylpropyl]-O-2-propenyl-L-serine, methyl ester (13 g, 29.8 mmol ) in methylene chloride/methanol (10:1, 220 mL). Cool to -78° C. and sparge with a mixture of ozone/oxygen for approximately 10 minutes until a blue color persists. Sparge with nitrogen for 10 minutes at -78° C. to remove excess ozone. Treat with methylsulfide (60 mL, 0.82 mol) and allow to warm to room temperature. Stir at room temperature for 2.5 hours, evaporate the solvent in vacuo and dissolve the residue in ethyl acetate (200 mL). Wash with water, saturated sodium chloride, dry (Mg SO4) and evaporate the solvent in vacuo to give the intermediate N-[2-(1,3-dihydro-1,3-dioxo-2H-isoindol-2-yl)-1-oxo-3-phenylpropyl]-O-2-oxoethyl-L-serine, methyl ester as a foam (13.6 g).

Source