Patent GB-695164-A (GB)
Title: Improvements in or relating to the production and use of acetals
IPC: C07D409/12
Filed: 1951-07-03
Abstract: The invention comprises acetals of the formula <FORM:0695164/IV (a)/1> where R is a cyclic divalent radical of aromatic character attached by nuclear carbon atoms and A is the residue of an aliphatic polyhydric alcohol whose carbon atoms attached to the oxygen atoms shown are in 1 : 2 or 1 : 3 relationship.  Thus A may be a polyvinyl alcohol residue <FORM:0695164/IV (a)/2> where the chain also contains a large number of recurring -CH2-CHOH- groups.  The chain may be an incompletely hydrolysed polyvinyl ester residue, in which case there are present hydroxyl groups esterified with, e.g. formic, acetic, chloracetic, propionic or butyric groups.  A copolymer of a vinyl ester with another monomer, e.g. ethylene, vinyl chloride or methyl methacrylate may also be used, after partial or complete hydrolysis. The polyvinyl alcohol or partial acetal may be reacted with an aldehydocarboxylic or aldehydosulphonic acid to acetalize further hydroxyl groups, e.g. 0.1-5 per cent.  The final products can be used in photographic emulsions (see Group XX) as both colour-former and water-permeable binding agent for silver halide, alone or with other colloids such as polyvinyl alcohol.  The acetals are prepared by reacting polyvinyl alcohol (or suitable derivative thereof) with a compound of the above general formula where A is the residue of an aliphatic 1 : 2- or 1 : 3-glycol (preferably having 2-4 carbon atoms), together with an aldehydo-acid if desired.  In the examples the following m-ureidobenzaldehyde ethylene glycol acetals are reacted with polyvinyl alcohol and sodium benzaldehyde-2-sulphonate: 3-cyano-acetylphenyl, 2 - chloro - 5 - cyanoacetylphenyl, 2 : 4 - dichloro - 5 - cyanoacetylphenyl, 2 - methyl-5 - cyanoacetylphenyl, 2 - methoxy - 5 - cyanoacetylphenyl, 2 - phenylmercapto - 5 - cyanoacetylphenyl, 3-carbomethoxy-5-cyanoacetylphenyl, 2 - cyanoacetyl - 5 - benzoylfuranyl and 2-cyanacetyl-8-dibenzofuranyl. A list is given of further residues R containing various carbocyclic and heterocyclic nuclei, including 5- and 6-membered rings with hetero-oxygen, nitrogen or sulphur and a fused-on benzene ring. The aldehydo-acid may be phthalaldehydic, glyoxylic or propionaldehyde-b -sulphonic acid.ALSO:The invention comprises acetals of the formula <FORM:0695164/IV (b)/1> where R is a cyclic divalent radical of aromatic character attached by nuclear carbon atoms and A is the residue of an aliphatic polyhydric alcohol whose carbon atoms attached to the oxygen atoms shown are in 1 : 2 or 1 : 3 relationship.  These are made from (1) compounds of the formula <FORM:0695164/IV (b)/2> (R1=C1-C4 alkyl) by reaction with acetonitrile in the presence of an alkaline condensing agent, or (2) the corresponding acetals of m-aminobenzaldehyde by reaction with OCN-R-CO-CH2CN.  In the examples, the following m-ureido-benzaldehyde ethylene glycol acetals are prepared by method (1): 3-cyanoacetylphenyl, 2 - chloro - 5 - cyanoacetylphenyl, 4 - chloro - 5 - cyanoacetylphenyl, 2 : 4 - dichloro - 5 - cyanoacetylphenyl, 2 - methyl - 5 - cyanoacetylphenyl, 2 - methoxy - 5 - cyanoacetylphenyl, 2 - phenylmercapto - 5 - cyanoacetylphenyl, 3 - carbomethoxy - 5 - cyanoacetylphenyl, 2 - cyanoacetyl - 5 - benzofuranyl, 2 - cyanoacetyl - 5 - thianaphthenyl and 2 - cyanoacetyl - 8 - dibenzofuranyl.  In a further example m-(4-cyanoacetylphenyl-ureido)-benzaldehyde ethylene glycol acetal is made by method (2).  In general A may be a residue of a 1 : 2 or 1 : 3-alkanediol of 2-4 carbon atoms, e.g. ethylene, propylene, trimethylene, 1 : 2- or 1 : 3-butylene glycol or glycerol.  R may be a hydrocarbon nucleus with 6-membered rings, e.g. benzene, naphthalene or anthracene, which may be substituted by alkyl, aryl, halogen, ether, thioether or carbalkoxy groups or may be a heterocyclic nucleus containing oxygen, sulphur or nitrogen in the ring, with or without a fused-on benzene ring; in particular, R may be a benzofuran nucleus with an alkyl, aryl or halogen substituent in the 3-position.  A list is given of suitable radicals R, containing as nuclei benzene, naphthalene, anthracene, phenanthrene, quinoline, pyridine, thianaphthene, isoquinoline, coumarone, benzopyran, benzimidazole, pyrazole, thiophen, naphthothiophen, naphthofuran, benzoxazole, benzthiazole, diphenyl and dibenzofuran rings, and as substituents methyl, ethyl, ethoxy, cyano, nitro, chloro, hydroxy, methoxy and phenyl groups.  The acetals used as starting materials for method (1) are obtained by reacting the corresponding acetals of m-aminobenzaldehyde with OCN-R-COOR1.  So prepared are the following m - ureido - benzaldehyde ethylene glycol acetals:- 3 - carbomethoxyphenyl, 2 - chloro - 5 - carbomethoxyphenyl, 2 : 4 - dichloro - 5 - carbomethoxyphenyl, 2 - methyl - 5 - carbomethoxyphenyl, 2 - methoxy - 5 - carbomethoxyphenyl, 2 - phenylmercapto - 5 - carbomethoxyphenyl, 3 : 5 - bis - carbomethoxyphenyl, 2 - carbomethoxy - 5 - benzofuranyl, 2 - carbethoxy-5-thianaphthenyl and 2-carbomethoxy-8-dibenzofuranyl. Isocyanates of the formul  OCN-R-COOR1 and OCN-R-CO-CH2CN are made by treating the corresponding amines with phosgene.  The following are thus made:-5-carbomethoxy - 2 - chlorophenyl, 5 - carbomethoxy - 4 - chlorophenyl, 5 - carbomethoxy - 2 : 4 - dichlorophenyl, 5 - carbomethoxy - 2 - methylphenyl, 5 - carbomethoxy - 2 - methoxyphenyl, 3 - carbomethoxyphenyl, 4 - cyanoacetylphenyl, 2 - phenylmercapto - 5 - carbomethoxyphenyl, 3 : 5 - bis - carbomethoxyphenyl, 2 - carbomethoxy - 5 - benzofuranyl, 2 - carbethoxy - 5 - thianaphthenyl and 8 - carbomethoxy - 2 - dibenzofuranyl.  Methyl 3-amino-4-chlorobenzoate is made by nitrating methyl 4-chlorobenzoate and reducing the product.  There are made similarly methyl 5 - amino - 2 - chlorobenzoate, methyl 5-amino-2 : 4 - dichlorobenzoate, methyl 3 - amino - 4 - methylbenzoate, methyl 3-amino-4-methoxybenzoate, methyl 3-aminobenzoate, dimethyl 5 - aminoisophthalate, methyl 5 - aminocoumarone - 2 - carboxylate, ethyl 5 - aminothianaphthene - 2 - carboxylate and methyl 8 - aminodibenzofuran - 2 - carboxylate.  The intermediate nitro-esters are described.  Methyl 3 - amino - diphenylsulphide - 4 - carboxylate is made by reacting methyl 4-chloro-3-nitrobenzoate with thiophenol and reducing the product.  4 - Cyanoacetyl - aniline is made by acid hydrolysis of 4-chloroacetyl-acetanilide and treatment of the product with potassium cyanide.