Ammonia → HCID 178445979, compound

Participants

Reaction Steps

110 mg of H-Arg-Arg-Pro-Phe-His-Sta-Sar-His-Lys-OMe (in the form of the trifluoroacetate; see Example 18) are dissolved in 1 ml of H2O and the pH value is adjusted to 5.0 with 0.5N NH3. After the addition of 20 μl of a 1% aqueous trypsin solution, the pH value is maintained at 5.0 by means of a pH stat while stirring at room temperature and adding 0.1N NH3. After approximately 10-15 minutes the absorption of the base is complete. The solution is acidified with 200 μl of glacial acetic acid, heated for 2 minutes in a boiling water bath, and lyophilised. In order to be converted into the acetate, the residue is dissolved in H2O and filtered slowly through a column (φ=0.7 cm; length=8 cm) of weakly basic ion exchanger (formexample Merck No. II) equilibrated in 0.05N acetic acid. The eluate is concentrated to a small volume and lyophilised, yielding H-Arg-Arg-Pro-Phe-His-Sta-Sar-His-Lys-OH (in acetate form) as an amorphous, readily water-soluble powder; Rf (D)=0.03; Rf (M)=0.03; Rf (O)=0.03.

Provenance & Evidence