Pesticide Science Society of Japan

Hydrogenated and Dichlorinated N-Phthaloyl-L-threonines and Their Dehydrated Phthalimides with Root Growth-promoting Activity for Rice Seedings

Satoko TANAKA and Masato KATAYAMA

J. Pestic. Sci. 25, 133-139 (2000)

Hydrogenated N-phthaloyl-L-threonines (P-Thrs) and their dehydrated phthalimides (2-phthalimido-2-butenoic acids, P-BTEAs), novel plant growth regulators, were readily synthesized. N-(4,5-Dichlorophthaloyl)-L-threonine and its dehydrated phthalimide also were synthesized. The synthetic P-Thrs and P-BTEAs had strong root growth-promoting activity for rice seedlings. The P-Thr activities were 1.6- to 2.2-fold the control value at 1¡ß10-4M, and the activities of the dehydrated P-BTEAs were a little higher, 2.1- to 2.6-fold the control value at the same concentration. Hydrogenation of the benzene ring of the phthaloyl group reduced root growth-promoting activity. Interestingly, none of the hydrogenated and dichlorinated P-Thrs and P-BTEAs had significant root growth-promoting activity for seedlings of lettuce, Chinese cabbage and black gram, like that of the original N-phthaloyl-L-threonine (P-Thr, 5a) and its dehydrated phthalimide (P-BTEA, 6a).


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