DIPHENYL HETEROCYCLIC HERBICIDES

摘要

1494877 Diphenyl heterocyclic compounds COMMONWEALTH SCIENTIFIC & INDUSTRIAL RESEARCH ORGANIZATION 7 Jan 1976 [10 Jan 1975] 515/76 Heading C2C The invention comprises compounds of general Formula I wherein each of R1 to R10, which may be the same or different, is hydrogen, lower alkyl, halogen, amino, nitro, cyano or -COR11 wherein R11 is hydroxy, lower alkoxy, aralkoxy, aryloxy, substituted or unsubstituted amino or -O#] n Mn# or -S#] n Mn# wherein Mn# is an ammonium, alkali metal or alkaline earth metal ion and n is 1 or 2 accordingly, R1 or R10 being -COR11, and wherein Q is a heterocyclic ring of general formula (A) or (B) wherein X is oxygen, sulphur, or substituted or unsubstituted secondary amino nitrogen, and each of Y and Z, which may be the same or different, is imino nitrogen or unsubstituted methine, subject to the proviso that, when Q is a ring of general formula (B) wherein Y is unsubstituted methine and X is substituted or unsubstituted secondary amino nitrogen, then Z is other than imino nitrogen. Compounds of Formula I in which Q is 1,2,4- triazole, 1,3,4-oxadiazole or 1,3,4-thiadiazole may be prepared by oxidizing a compound of Formula I in which R1 or R10 is alkyl to convert the latter to -COR11. Compounds of Formula I in which Q is isooxazole may be prepared by cyclizing a compound of formula (which itself may be obtained from the corresponding diketone and hydroxylamine). Compounds of Formula I in which Q is isooxazole and R5 is -COR11 may be obtained by reacting with hydroxylamine a compound of Formula III where X1 is halogen. Compounds of Formula I where Q is 1,3,4-oxadiazole may be prepared by cyclizing a compound of Formula IV Compounds of Formula I where Q is thiazolyl may be prepared by reacting together the two compounds The precursor of Formula III, X = Br and all R's = H, is obtained by bromination of the corresponding compound (α-phenacyl phthalide) in which X=H, which is obtained from 2- carboxybenzaldehyde and acetophenone. (IV), R5 = -COOH and other R's=H, is obtained from benzyl hydrazide and 2-carboxybenzaldehyde. o-Carboxyphenacyl bromide (obtained by bromination of o-carboxyacetophenone) with thiobenzamide in ethanol gives 2-phenyl-4-(oethoxycarbonylphenyl)-thiazole the ester group of which is then hydrolysed to the corresponding acid group. o-Toluylhydrazide with benzonitrile gave 3-o-tolyl-5-phenyl-1,2,4-triazole, the methyl group of which is oxidized to the carboxyl group. Compounds of Formula I, may be used to regulate the growth of plants.