Reaction #433626

Reaction equation

H2N-Cys(Trt)-OMe

Fmoc-Cys(Trt)-OH

sulfuric acid

→

25

Fmoc-Cys(Trt)-OMe

Solvents

MeOH

Conditions

Workup

1. 1
   TemperatureThe reaction mixture was refluxed for 4 hr
2. 2
   Otherthe solvent was removed
3. 3
   workup.ADDITIONThe mixture was then mixed with ethyl acetate
4. 4
   Washwashed with water, saturated NaHCO3, and brine
5. 5
   OtherRemoving the solvent under vacuum

Procedure

and H2N-Cys(Trt)-OMe 26. 7.2 g (12.3 mmol) of Fmoc-Cys(Trt)-OH was dissolved in 70 ml of MeOH and added 1.5 ml of conc. sulfuric acid. The reaction mixture was refluxed for 4 hr, the solvent was removed. The mixture was then mixed with ethyl acetate, and washed with water, saturated NaHCO3, and brine. Removing the solvent under vacuum gave 25 as a white foamy solid. The crude product was dissolved in 20 ml of 20% piperidine solution in DMF. After 2 hr, the solvent was removed. Silicagel chromatography (CH2Cl2:MeOH=10:1) gave 4.0 g (86% two step yield) of 26 as a white solid.

Source