Z-Sta-Ala-OC(CH3)3 → Z-Sta-Ala-OH

Participants

Reaction Conditions

Reaction Steps

470 mg of Z-Sta-Ala-OC(CH3)3 (from stage 13.1) are dissolved in 10 ml of trifluoroacetic acid and the solution is stirred for 10 minutes at 25° C. The solvent is then removed in a rotary evaporator and the residue is flash-chromatographed over 200 g of silica gel (eluant first chloroform/methanol/concentrated aqueous ammonia solution [40:10:1], then chloroform/methanol/concentrated aqueous ammonia solution [5:3:1]). The product-containing fractions are combined and concentrated by evaporation, the residue is taken up in chloroform and the chloroform solution is extracted with dilute hydrochloric acid and saturated sodium chloride solution, dried and concentrated by evaporation. After drying the residue in a high vacuum, Z-Sta-Ala-OH is obtained in the form of a colourless foam; Rf (G)=0.43.

Provenance & Evidence