Structure of the cyclic tetrapeptide tentoxin. Crystal and molecular structure of the dihydro derivative

Abstract

The dihydro reduction product of tentoxin (I), a phytotoxic tetrapeptide from Alternaria tenuis Nees., is shown by X-ray crystallography and the known absolute configurations of its amino acid constituents to be cyclo(N-methyl-L-alanyl-L-leucyl-N-methyl-D-phenylalanyl-glycyl); tentoxin is its dehydrophenylalanyl analogue.