Aryloxyalkanoic acids

According to the initial aryloxyalkanoic acids used, numerous benzo-furans with various substituents have been prepared in this way. 

The cyclization of o-carbonylated a-aryloxyalkanoic acids or esters (Rossings method) has yielded numerous benzo[6]furans (see Section 3.12.5). The condensation of o-hydroxylated... 

Substitution. Alkylation, and Rearrangement. The reaction of alkaline pheno.sides with alkyl 5-2-ichlorol- or 5-2-ttnesyloxyipropuinaie gives optically active JJ-2-aryloxyalkanoic acid esters in good chemical and optical yields t >97 . cet. The reaction is utilized in the synthesis orseveral phenoxy herhicides. 

The decomposition of a number of peresters of alkoxy- and aryloxyalkanoic acids have been studied and the data are presented in Table 94. For comparison. 

Massolini, G., Calleri, E., Lavecchia, A., Loiodice, F., Lubda, D.,Temporini, C., Fracchiolla, G.,Tortorella, P., Novellino, E., Caccialanza, G. Enantioselective hydrolysis of some 2-aryloxyalkanoic acid methyl esters and isosteric analogues using a penicillin G acylase-based HPLC monolithic silica column, Anal. Chem.,... 

Field dosages often span a very broad range, and the typical application rates , shown in Table 8.1, are for general comparison only. Nevertheless, these numbers indicate how field a.i. rates have decreased historically, as more active molecules have been developed examples include the neo-nicotinoid insecticides, triazole fungicides and sulfonylurea herbicides, which are one to two orders of magnitude more active than the early organochlorine, copper and aryloxyalkanoic acid pesticides, respectively. 

The Pesticide Manual describes 5 pyridine carboxylic acid derivatives, 3 benzoic acids, and 10 aryloxyalkanoic acids in current use as herbicides. 2,4,5-T seems to be banned worldwide and is not included in the current issue (Tomlin, 2000) but is described in earlier issues (e.g., Worthing, 1979). It was first registered in 1948 by Amchem Products, Inc., Pennsylvania, and the Dow Chemical Company, and was mainly used to control shrubs and trees, for example, in forests and along railways. Although the content of dioxin was eventually controlled, with a limit of <0.05 mg/kg in the preparation, it was banned soon after the termination of its use in Vietnam. Other products with 2,4,5-trichlorophenol were also banned or restricted after the Seveso accident (see Hay, 1978a, 1978b). 2,4-D is also produced from a chlo-rophenol and may contain dioxins, but of the much less toxic congeners. It... 

Various other aryloxyalkanoic acids given subcutaneously reduce vascular permeability in the mouse > . Anti-inflammatory activity has been claimed for two indanoxybutyric acids . o-Ethoxy-substituted phenoxyethylamines, in oral doses of 25 mg/kg, are claimed to inhibit ultra-violet erythema in the... 

The Pesticide Manual describes 5 pyridine carboxylic acid derivatives, 3 benzoic acids, and 10 aryloxyalkanoic acids in current use as herbicides. 

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