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Abstract
Di- and tri-peptides with α -aminopropanephosphonic acid as the acid-terminal residue have been prepared containing L-alanyl, D-alanyl, DL-alanyl, and glycyl groups. Nmr parameters (1H, 13C and 31P) are reported for solutions of the peptides in D2O and are discussed. Diastereoisomeric forms of the L-ala-, and L-ala-L-ala-peptides were separated on a cation exchange-column and it was found in each case that the methine and carbonyl groups of the alanyl residue that is adjacent to the aminophosphonic group exhibit slightly different 13C chemical shifts in each of the two diastereoisomers. Fast-atom bombardment mass spectrometry gave characteristic [MH]+ ions, which usually appeared as the base peak. Fragment ions were formed by the elimination of α-lactam units from the amino-carboxylic acid residues and phosphorous acid from the aminophosphonic acid residue. The L-ala-peptides showed similar activity to that of α-aminopropanephosphonic acid when applied as seed-dressings at 400 ppm for the control of Drechslera spp. Gyycyl peptides were slightly less active but the D-ala-peptides had little or no activity.