Patent GB-813367-A (GB)
Title: Substituted chlorophenoxyacetic acids
IPC: C07C37/20
Filed: 1957-06-06
Abstract: The invention comprises compounds of the general formula: <FORM:0813367/IV (b)/1> where X is hydrogen or a lower alkyl group containing up to 4 carbon atoms, together with the salts, esters and amides of these acids.  The acid derivatives mentioned are the alkali metal or aliphatic amine salts, alkyl esters and the N-mono- or di-alkyl substituted amides.  The preferred compounds are 2-hydroxymethyl-4-chlorophenoxyacetic acid and 2-hydroxymethyl - 4 - chloro - 5 - methylphenoxy - acetic acid which are stated to have plant growth-regulating properties.  They may be prepared by reducing the corresponding compound having a formyl group in the 2-position. The reduction of the formyl group to hydroxymethyl may be carried out with hydrogen in the presence of Raney nickel or with formaldehyde and an alkali metal hydroxide.  They may also be prepared by reacting a phenol <FORM:0813367/IV (b)/2> with a halogenated acetic acid, or a salt, ester or amide of the acid.  The preferred halo compounds are the chloro and bromo compounds and the reaction is preferably carried out in the presence of an alkaline condensation agent such as sodium or potassium hydroxide or sodium carbonate.  The phenol and acid may also be reacted as their alkali metal salts and the reaction may be carried out in an alcohol or hydrocarbon solvent.  In examples: (i) 2-formyl - 4 - chlorophenoxyacetic acid is reduced with 30 per cent formaldehyde and sodium hydroxide; (ii) as (i) but reducingwith hydrogen in the presence of Raney nickel; (iii) 2 - formyl - 4 - chlorophenoxyacetamide is reduced with hydrogen in the presence of Raney nickel; (iv) 2-hydroxy-methyl-4-chlorophenol is reacted with monochloracetic acid in the presence of sodium hydroxide; (v) 2-hydroxymethyl - 4 - chloro - 5 - methyl phenol is reacted with monochloracetic acid in the presence of sodium hydroxide and sodium iodide; (vi) N : N-diethyl-2-formyl-4-chlorophenoxyacetamide is reduced with hydrogen in the presence of Raney nickel; (vii) methyl 2-formyl-4-chlorophenoxy acetate is reduced with hydrogen in the presence of Raney nickel.  The preparation of 2-formyl-4-chlorophenoxy acetamide and its N : N-diethyl derivative from the corresponding acid and of 2-hydroxymethyl-4-chloro-5-methyl phenol is described.ALSO:Plant growth regulant compositions, said to be useful for increasing stem thickness, promoting root formation and producing parthenocarpic fruits, contain at least 0,1 p.p.m. of a compound of the general formula <FORM:0813367/I/1> where X is hydrogen or an alkyl group containing up to 4 carbon atoms, or a salt, amide or ester thereof together with a carrier or diluent.  The compositions may be used in the form of an aqueous solution, e.g. of an alkali metal salt, which may contain wetting, emulsifying or dispersing agents or in a solid form using an inert diluent such as talc or clay.  Specific compositions mentioned include wettable powders containing acid or amide with a diluent powder and wetting agent, oil emulsions containing one or more esters and micronised oil suspensions of acid or amide. In example 2 a composition containing 2 per cent. active compound is prepared with 2-hydroxymethyl-4-chloro-phenoxy acetic acid, sodium hydroxide, acetone, glycerine and water.  This may be diluted to a 0,002 to 0,01 per cent. solution for use in promoting root growth or to a 0,01 to 0,02 per cent. solution for producing parthenocarpic fruits.  A 1 per cent. solution is mentioned for use in increasing stem thickness.