Patent GB-715446-A (GB)
Title: Aldehydes and their acetals
Filed: 1952-10-03
Abstract: The invention comprises acetals of aldehydes of the formula <FORM:0715446/IV (a)/1> especially those formed with polymeric alcohols having a large number of intralinear recurring -CH2-CHOH- units; one of X and Y is hydroxyl and the other is hydrogen, halogen, alkyl or aryl; the benzene ring may be further substituted but the position para to the hydroxyl must be free or occupied by a group readily replaceable in a dye coupling reaction; R is a divalent radical attached by carbon atoms, one of which is part of an aromatic (carbocyclic or heterocyclic) ring and the other is the same or a part of a methylene or polymethylene group attached to said ring directly or via an ether-oxygen linkage.  In preferred compounds X is hydroxyl, Y is hydrogen and R is an aromatic ring system, a diphenyl ether residue or a phenoxyalkylene group.  The polymeric alcohol may be a partly or completely hydrolysed polyvinyl ester, e.g. formate, acetate, chloracetate, propionate or butyrate, or copolymer of a vinyl ester with another vinyl compound, e.g. vinyl chloride, methyl methacrylate or ethylene (as in Specifications 600,023 and 607,911). Other hydroxyl groups in the polymer chain may be acetalized with, e.g. formaldehyde, acetaldehyde, butyraldehyde, benzaldehyde, or especially an aldehyde containing a solubilizing group, e.g. o-sulphobenzaldehyde, phthalic monaldehyde, glyoxylic acid or propionaldehyde-b -sulphonic acid. Such acid groups may be present as their alkali metal, ammonium or amine salts.  The polymeric acetals are made by reacting polyvinyl alcohol with the free aldehydes or acetals formed from them and monomeric alcohols or glycols.  In the examples, polyvinyl acetals are made from the following aldehydes: (1) p-(o-hydroxyphenyl-carbamyl)-benzaldehyde, b -[p-(o-hydroxy - m - chlorophenyl - carbamyl) - phenoxy] - propionaldehyde, b  -[p - (m - phenyl - o - hydroxyphenylcarbamyl) - phenoxy] - propionaldehyde; (2) p-[p-(o-hydroxyphenylcarbamyl) - phenoxy] - benzaldehyde, p - [p - (m - hydroxyphenylcarbamyl) - phenoxy] - benzaldehyde, p - [p - (o - hydroxyphenylcarbamyl) - o - nitrophenoxy] - benzaldehyde, p - [(o - hydroxyphenylcarbamyl) - methoxy] - benzaldehyde, b -[p - (o - hydroxyphenylcarbamyl) - phenoxy] - propionaldehyde, 2 - (o - hydroxyphenylcarbamyl) - coumarone - 5 - aldehyde, 2 - (o - hydroxyphenylcarbamyl) - dibenzofuranaldehyde.  In cases (2) some of the hydroxyl groups in the polymer chain are acetalized with sodium benzaldehyde - 2 - sulphonate.  A list is given of further suitable aldehydes in which R is a benzene, naphthalene, furan, thiophene, thionaphthene, pyridine or quinoline ring.  Specification 662,793 also is referred to.ALSO:The invention comprises aldehydes of the formula: <FORM:0715446/IV (b)/1> and their acetals formed with monohydric and polyhydric alcohols; one of X and Y is hydroxyl and the other is hydrogen, halogen, alkyl or aryl; the benzene ring may be further substituted but the position para to the hydroxyl must be free or occupied by a group readily replaceable in a dye coupling reaction; R is a divalent radical attached by carbon atoms one of which is part of an aromatic (carbocyclic or heterocyclic) ring and the other is the same or a part of a methylene or polymethylene group attached to said ring directly or via an ether-oxygen linkage.  In preferred compounds X is hydroxyl, Y is hydrogen and R is an aromatic ring system, a diphenyl ether residue or a phenoxyalkylene group. The acetals are preferably formed with 1 : 2 or 1 : 3-alkane diols of 2-4 carbon atoms.  The compounds are made by N-acylation of o- and m-aminophenols with the appropriate acyl halides.  In the examples, o-aminophenol is condensed with the chlorides of the following acids: diphenylether-4 - aldehyde - 41 - carboxylic acid, 2 - nitro-diphenylether - 41 - aldehyde - 4 - carboxylic acid (dimethyl acetal formed during isolation), 4-carboxy-benzal diacetate, 4-formyl-phenoxy-acetic acid, b -(4-carboxyphenoxy)-propionaldehyde ethylene glycol acetal, 2-carboxy-coumarone - 5 - aldehyde and 2 - carboxy - di-benzofuran-aldehyde; m-aminophenol is condensed with the chloride of 4-carboxy-diphenyl-ether - 41 - aldehyde ethylene glycol acetal; 2 - amino - 6 - chlorophenol and 2 - amino - 6-phenyl-phenol are condensed with the chloride of b  - (4 - carboxy - phenoxy) - propionaldehyde ethylene glycol acetal.  The above carboxylic chlorides are made from the corresponding acids and thionyl chloride, except for that of 4-carboxy-benzal diacetate which is prepared by oxidizing p-toluyl chloride with chromic acid in acetic acid and anhydride.  The chloride of 4-carboxy-diphenylether-41-aldehyde ethylene glycol acetal is made from the acid and thionyl chloride. The following carboxylic acids are made by hydrolysis of their esters: 4-carboxy-diphenyl-ether-41-aldehyde and its ethylene glycol acetal, 2 - nitro - 4 - carboxy - diphenylether - 41-aldehyde, b  - (4 - carboxyphenoxy) - propionaldehyde ethylene glycol acetal, 2-carboxy-coumarone - 5 - aldehyde and 2 - carboxy-dibenzofuran - aldehyde.  4 - formyl - phenoxy-acetic acid is prepared by condensing p-hydroxy-benzaldehyde with chloracetic acid.  The following aldehydes are made by oxidizing the corresponding chloromethyl compounds with 2-nitropropane and sodium methoxide: methyl diphenylether - 4 - aldehyde - 41 - carboxylate, methyl coumarone - 5 - aldehyde - 2 - carboxylate and methyl dibenzofuranaldehyde-2-carboxylate.  Direct chloromethylation is used for the preparation of methyl 4-chloromethyl-diphenyl-ether - 41 - carboxylate, methyl 5 - chloro-methyl - coumarone - 2 - carboxylate and methyl chloromethyldibenzofuran - 2 - carboxylate.  Methyl esters of the following are made by direct esterification: diphenylether-4-carboxylic acid, coumarone-2-carboxylic acid and dibenzofuran-2-carboxylic acid.  Diphenylether - 4 - carboxylic acid and dibenzofuran-2-carboxylic acid are made by hypochlorite oxidation of the corresponding methyl ketones.  4 - Phenoxyacetophenone and 2 - acetyldibenzofuran are prepared by the Friedel Crafts method (using acetic anhydride) from diphenyl-ether and dibenzofuran respectively. 4 - Carbomethoxy - diphenylether - 41 - aldehyde ethylene glycol acetal is made from the aldehyde and ethylene glycol.  2 - Nitro - 4 - carbomethoxy - diphenylether-41-aldehyde is prepared by condensing p-hydroxybenzaldehyde with methyl 3-nitro-4-chlorobenzoate.  b  - (4 - carbethoxyphenoxy) - propionaldehyde ethylene glycol acetal is made by reacting acrolein with ethylene glycol and hydrogen chloride and condensing the resulting b -chloropropionaldehyde ethylene glycol acetal with ethyl p-hydroxy-benzoate.  2 - Amino - 6 - phenylphenol is prepared by nitrating o-hydroxydiphenyl, reducing the product and hydrolysing the resulting 2-methyl-7-phenylbenzoxazole.  2 - Amino - 6 - chlorophenol is made as in Specification 562,205.  Other products are listed in which R is a benzene, naphthalene, furan, thiophene, thionaphthene, pyridine or quinoline ring. This nucleus may carry inert substituents such as halogen, nitro or carbalkoxy.