Abstract
N-(Substituted phenylcarbamoyl) amino acid derivatives [N-(3, 4-dichlorophenylcarbamoyl) amino acids (DA), N-(substituted phenylcarbamoyl) DL-alanines (SA), N-(3, 4-dichlorophenylcarbamoyl)-N-methyl amino acids (DMA), N-alkyl-N-(3, 4-dichlorophenylcarbamoyl)β-alanines (βDA), N-methyl-N-(substituted phenylcarbamoyl) β-alanines (βSM) and N-(3, 4-dichlorophenylcarbamoyl)-N-methyl β-alanine thiol esters (βDMT)] were examined on their herbicidal activity by the pot tests.
(1) Activity of DA was generally low and the compounds with an DL-alanine residue showed the strongest activity among DA. Difference between free acid form and methyl ester of carboxyl groups of amino acid residues was not observed. Among SA, N-(3, 4-dichlorophenylcarbamoyl) DL-alanine showed the strongest activity.
(2) Activity of DMA was generally found high. Among them, methyl esters of glycine, β-alanine and γ-aminobutyric acid showed rather potent activity. Especially, β-alanine methyl ester (MCMD) exhibited excellent margin of selectivity for wheat under the condition of foliar application.
(3) Activity of β-DA depended upon the kinds of alkyl group and changed continuously against those of the group. The compound having iso-propyl group showed the strongest activity but caused serious damage on wheat.
(4) In the methyl ester form of β-SM, activity varied in proportion to the hydrophobic constant (π) of substituents. In the free acid form of β-SM, however, activity varied in inverse proportion to π. Among β-DMT, ethyl thiol ester showed the strongest activity.
