Patent GB-1479902-A (GB)
Title: Esters and amides of trisubstituted hydroxyphenylalkanoic acids
IPC: C07C69/24
Filed: 1974-09-24
Abstract: 1479902 Esters and amides of trisubstituted hydroxyphenylalkanoic acids CIBA-GEIGY AG 24 Sept 1974 [25 Sept 1973] 41450/74 Heading C2C [Also in Divisions C3 and C5] The invention comprises the esters and amides of Formulµ I and II wherein R, R<SP>1</SP> and R<SP>2</SP> are independently C 1-8  alkyl or C 5-6  cycloalkyl groups-provided that not more than two of R, R<SP>1</SP> and R<SP>2</SP> are cycloalkyl-or R<SP>1</SP> and R<SP>2</SP> together form a butylene chain; A is a straight or branched chain C 1-8  alkylene group; n is an integer of 1-6; m is an integer of 1 to 4; when n is 1, R<SP>3</SP> is hydrogen or a C 1-30  alkyl, C 5-6  cycloalkyl, phenyl, (C 1-18  akyl)phenyl group or an alkylthioethyl group having 5-27 atoms in the chain; when n is 2, R<SP>3</SP> is a C 2-12  alkylene, C 5-8  cycloalkylene, alkylene interrupted by a cycloalkane group and containing a total of 7 to 10 carbon atoms, thiobisalkylene of 5-9 chain atoms, alkyleneoxyalkylene having 5-9 chain atoms or a 8- 101 atom polyoxyalkylene group; when n is 3- 6, R<SP>3</SP> is a 3 to 6 valent C 3-10  cyclic or acyclic hydrocarbon radical each valence bond of which is attached to a different carboxylic ester oxygen atom; R<SP>4</SP> is hydrogen or a C 1-8  alkyl or C 5-6  cycloalkyl group or, when m is 2, R<SP>4</SP> and R<SP>5</SP> together form a piperazinyl group incorporating both nitrogen atoms, or a group of Formula IIa wherein R, R<SP>1</SP> and R<SP>2</SP> are as defined above; when m is 1, R<SP>5</SP> is H, C 1-24  alkyl or phenyl optionally substituted by C 1-18  alkyl group(s); when m is 2, R<SP>5</SP> is C 2-18  alkylene, polyoxyalkylene of 8 to 11 carbon atoms; when m is 3 or 4, R<SP>5</SP> is a tri- or tetravalent C 3-8  hydrocarbyl radical each free valence bond of which is attached to a different amide nitrogen atom. 4-Hydroxyphenylacetic acids of Formula I are prepared by hydrolysis of the corresponding phenylacetonitriles and are esterified by heating with methanol in the presence of hydrogen chloride. Other esters and amides are obtained from this methyl ester by transesterification with alcohols or polyols or by reaction with suitable amines. Methyl 4-hydroxyphenylpropionates of Formula I are obtained by reaction of the corresponding substituted phenols with methylacrylate and may be hydrolysed to obtain the free acid, transesterified with alcohols or polyols to obtain other esters of Formula I, or reacted with appropriate amines to obtain the amides of Formula II. 2,3 - Dimethyl - 6 - (1,1,3,3 - tetramethylbutyl)- phenol and 2 - tert.butyl - 5,6,7,8 - tetrahydro - 1- naphthol are prepared by alkylation of 2,3-dimethylphenol with 2,4,4-trimethyl-pentene-1 and isobutylene respectively in the presence of p-toluenesulphonic acid monohydrate. 6 - Tert - butyl - 2,3 - dimethyl - 4 - (dimethylaminomethyl)phenol is prepared by reaction of 6-t.butyl-2,3-dimethylphenol with formaldehyde and dimethylamine and is further reacted with sodium cyanide to obtain 5-tert-butyl-2,3- dimethyl-4-hydroxyphenylacetonitrile The esters and amides of Formulµ I and II have application for stabilizing organic materials against oxidative, thermal and u.v. light deterioration.