X-Ray crystal structure determination and synthesis of the new isonitrile-containing antibiotics, hazimycin factors 5 and 6

Abstract
Two compounds of a new class of antibiotics, hazimycin factors 5 and 6, which are interconvertible in a base-catalysed process, are each shown to be di-tyrosine analogues containing two isonitrile groups; their synthesis by two routes, one of which involves oxidative coupling of N-formyl-L-typrosine methyl ester with horse-radish peroxidase, is described.