Aryloxyacetic acid

Aryloxyacetic acids. Phenols, in the presence of alkah, react with chloroacetic acid to give aryloxyacetic acids ... 

To a mixture of 10 g. of the compound and 3-5 ml. of 33 per cent, sodium hydroxide solution in a test-tube, add 2-5 ml. of 50 per cent, chloroacetic acid solution. If necessary, add a little water to dissolve the sodium salt of the phenol. Stopper the test-tube loosely and heat on agently-boiling water bath for an hour. After cooling, dilute with 10 ml. of water, acidify to Congo red with dilute hydrochloric acid, and extract with 30 ml. of ether. Wash the ethereal extract with 10 ml, of water, and extract the aryloxyacetic acid b shaking with 25 ml. of 5 per cent, sodium carbonate solution. Acidify the sodium carbonate extract (to Congo red) with dilute hydrochloric acid, collect the aryloxyacetic acid which separates, and recrystallise it from hot water. 

The derivative selected in any particular instance should be one which clearly singles out one compound from among all the possibilities and thus enables an unequivocal choice to be made. The melting points of the derivatives to be compared should differ by at least 5-10°. Whenever possible, a derivative should be selected which has a neutralisation equivalent as well as a melting point (e.g., an aryloxyacetic acid derivative of a phenol. Section IV,114,4, or a hydrogen S nitrophthalate of an alcohol. Section 111,25,5). 

Disubstituted aryloxyacetic acid derivatives related to clofibrate have been intensively studied in an attempt to get around the side effects of the latter drug. 

Branched aryloxyacetic acids often have hypo-... 

Halogen acid furnaces, 13 179 Halogenated alkyl phosphates/ phosphonates, 11 489-496 Halogenated aromatic hydrocarbons (HAHs), 13 135 toxic responses to, 13 138 Halogenated aryloxyacetic acids,... 

Arsenic, detection of, 1043 Aryloxyacetic acids, 682 Asbestos-sodium silicate stoppers, 494 Aspirin, 996... 

Rearrangements have been observed in the case of aryloxyacetic acids a-substituted by an aryl group (96, R = H, R2 = Ph, X = OH), which give 3-phenyl-2(3//)-benzofuranone (98).278 2,4-Dichlorophenoxy-acetic acid and its chloride do not undergo ring closure by any method.279... 

The analysis depicted for (64) reveals that the synthesis of benzofuran involves the conversion of salicylaldehyde into the corresponding aryloxyacetic acid by reaction with sodium chloroacetate in the presence of alkali, followed by heating with a mixture of acetic anhydride, acetic acid and sodium acetate (Expt 8.24). The ensuing cyclisation may be regarded as an internal Perkin reaction (Section 6.12.3, p. 1036) accompanied by a decarboxylative dehydration step. 

Others CPSs have been prepared in a similar way and characterized at different steps by physicochemical methods. For example, the structure of the chiral selector iV-[2 -(5)-hydroxypropyl]-Ar, /V -bis(3,5- dichlorobenzoyl)-(f ,f )-tra i- 1,2-diamino-cyclohexane was solved by X-ray analysis and its absolute configuration confirmed unambiguously [73]. These CPS phases were used to resolve a large number of racemic mixtures belonging to different classes of organic compounds, such as a-aryloxyacetic acids, alcohols, sulfoxides, selenoxides, phosphinates, amino acids, amino alcohols, etc. 

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