Untersuchungen über das konfigurative Verhalten von Isoleucin bei der Waldenschen Umkehrung

Abstract

The rates of alkaline cleavage of Br from 4 isomeric [alpha]-brom-[beta]-methyl-[beta]-ethyl propionylleucines were similar to the relative rates for the [alpha]-brompro-pionylnorvalines previously investigated in that the rates were higher for d-, l-, and l-, d- than for l-, l-, and d-, d-forms. No inversion of isoleueine occurred on conversion to [alpha]-brom-[beta]-methyl-[beta]-ethylpropionic acid and subsequent aminization back to isoleueine, which corresponded to the condition previously found for valine. Specific rotations and melting points are given for the four acids. dl-[alpha]-brom-[beta]-methyl-[beta]-ethylpropionylglycine and dl-[alpha]-brom-[beta]-methyl-[beta]-ethylpropionyl-Z-tyrosine were also prepared.