Synthesis of Angiotensins by the Solid-Phase Method

The new method of solid-phase synthesis was applied to the preparation of isoleucine5-angiotensin II. These syntheses started with t-butyloxycar-bonylphenylalanylcopolystyrene-divinylbenzene, ended with chromatographically pure octapeptide, and gave an over-all yield of 56%. The synthetic angiotensin possessed full oxytocic activity. Since the rearrangement of the α-aspartyl bond to the β-aspartyl bond had been reported under conditions similar to those used in the synthesis, it was then ascertained by a variety of methods that this rearrangement did not occur in solid-phase synthesis. The analogs, asparagine1-isoleucine5-angiotensin II and β-aspartic1-isoleucine5-angiotensin II, were also synthesized.