Synthesis and Herbicidal Properties of N-(Benzylideneamino),N-(Benzylamino), and N-(Phenylazo) Heterocycles

Abstract

The search for common structural features within the great variety of organic compounds acting as PS II inhibitors revealed the existence of a vinylogous relationship. By applying hetero-analogy and the principle of vinylogy, a simple model is proposed which unifies the structures of the vast array of PS II inhibitors. In the present work, its predictive value has been tested and confirmed by the preparation of a variety of N-(benzylideneamino) and N-(phenylazo) heterocycles. In these bridged vinylogous ureas, carbamates, and amides, the aromatic and heterocyclic rings are connected via diatomic linkages capable of transmitting substituent conjugative effects. N-(Benzylideneamino) and N-(phenylazo) heterocycles derived from N-aminoimidazolidin-2-one, 4-amino-1,2,4-triazol-3(2H)-one, and 1-aminohydantoin are among the most active members. In general, herbicidal activity is increased with lipophilicity imparted by a meta--substituent on phenyl. meta-CF 3 (and OCF 3 ) derivatives which showed tolerance on cotton produced severe bleaching, inhibiting carotenoid biosynthesis at the phytoene desaturation stage.Fundamental problems in a given area of research can often be solved by finding analogies with problems previously solved in other areas of research. This rarely yields the whole solution, but it can provide useful insights and intuitions.For example, the principles of vinylogy and hetero-analogy which are almost as old as organic synthesis itself are familiar to chemists in the solution of certain types of synthetic problems. Since R. C. Fuson's review article (1) in 1935, examples of vinylogous relationships have increased

Synthetical Application of Alkyl 2-isothiocyanatocarboxylates. A Simple Synthesis of 5-Substituted-3-amino-2-thioxo-4-imidazolidinones (3-Amino-2-thiohydantoins)

“…Numerous heterocyclic compounds having a thiourea or a thiosemicarbazide moiety have been found to be active as agrochemicals [1][2][3]. As a part of our research in the synthesis of novel heterocycles derived from α-aminoacids we have found a very simple way leading to the 3-aminothiohydantoins.…”