Patent GB-704558-A (GB)
Title: Improvements in or relating to acetals, and photographic emulsions containing such acetals
IPC: C07D317/14
Filed: 1951-07-03
Abstract: The invention comprises acetals of the formula <FORM:0704558/IV (a)/1> where R is a cyclic divalent radical of aromatic character attached by nuclear carbon atoms, Q is -NHCO- or -NHSO2-, Z is -CH2CN or -OR1, R1 is alkyl of 1-4 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:0704558/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 (see Specifications 598,475 and 607,911).  The polyvinyl alcohol or partial acetal may be reacted with an aldehydo-carboxylic or aldehydosulphonic acid to acetalise further hydroxyl groups, e.g. 0.1-5 per cent.  The final products can be used in photographic emulsions (see Group XX).  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). In the examples the following N-derivatives of m-aminobenzaldehyde polyvinyl acetal are prepared: (1) p-cyanoacetyl-benzoyl, (2) 5-cyanoacetylthiophen-2-carboxyl, (3) m-cyanoacetyl-benzoyl, (4) 2-cyanoacetyl-naphthalene-sulphonyl, (5) 2-cyanoacetylcoumarone-5-sulphonyl, (6) p-(3-cyanoacetyl-5-methyl-1-pyrazolyl)-benzoyl and (7) p-(3-cyanoacetyl-5-phenyl-1-pyrazolyl)-benzoyl.  With the exception of cases (2) and (7) sodium benzaldehyde-2-sulphonate is also present in the reaction mixture.  In case (3) the polyvinyl alcohol is reacted with the free aldehyde. Specification 635,294 also is referred to.ALSO:The invention comprises acetals of the formula <FORM:0704558/IV(b)/1> where R is a cyclic divalent radical of aromatic character attached by nuclear carbon atoms, Q is -NHCO- or -NHSO2-, Z is -CH2CN or -OR1, R1 is alkyl of 1-4 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 by reacting the corresponding acetals of m-aminobenzaldehyde with the carboxylic acid chloride or sulphonyl chloride derivatives of R-CO-Z; the cyanoacetyl compounds may also be made from the carbalkoxy compounds and acetonitrile in the presence of an alkaline condensing agent.  In the examples the following N-derivatives of m-aminobenzaldehyde ethylene glycol acetal are prepared:- p-cyanoacetyl-benzoyl, 5-cyanoacetyl-thiophene-2-carboxyl, 2-carbomethoxy-naphthalenesulphonyl (converted to 2-cyanoacetyl), 2-carbomethoxy - coumarone - 5 - sulphonyl (converted to 2-cyanoacetyl), p-carbethoxy-benzoyl (converted to p-cyanoacetyl), 5-carbomethoxythiophene-2-carboxyl (converted to 5-cyanoacetyl), p-(3-carbethoxy-5-methyl-1-pyrazolyl)-benzoyl (converted to 3-cyanoacetyl), p-(3-carbethoxy - 5 - phenyl - 1 - pyrazolyl) - benzoyl (converted to 3-cyanoacetyl).  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, hydroxy, chloro, methoxy and phenylthio groups.  Cyanoacetyl - carboxylic chlorides CN-CH2-CO-R-CO-Cl are prepared from the diesters of acids R (COOH)2 by treatment with acetonitrile to give the ester of CN-CH2-CO-R-COOH, hydrolysis to free acid and treatment with thionyl chloride. There are thus prepared methyl 4-cyanoacetylbenzoate, methyl 2-cyanoacetylthiophene-5-carboxylate and methyl 3-cyanoacetylbenzoate and the corresponding free acids and acid halides.  Carbalkoxy - sulphonyl chlorides R1O-CO-R-SO2-Cl are made by treating R-COOR1 with chlorosulphonic acid, e.g. 2-carbomethoxynaphthalene-sulphonyl chloride and 2-carbomethoxy-benzofuran-2-sulphonyl chloride. Carbalkoxy-carboxylic chlorides R1O-CO-R-CO-Cl are obtained from the corresponding acids and thionyl chloride; there are thus made 5 - carbomethoxy - thiophene - 2 - carboxylic chloride, ethyl 1-(p-chloroformylphenyl)-5-methylpyrazole - 3 - carboxylate and the corresponding 5-phenyl compound. 5-Carbomethoxy-thiophene-2-carboxylic acid is prepared by partial hydrolysis of the dimethyl ester.  Ethyl 1-(p-carboxyphenyl)-5-methylpyrazole-3-carboxylate is made by reacting ethyl acetopyruvate with p-carboxy-phenylhydrazine. The corresponding 5-phenyl compound is made similarly.  Specification 531,246 is referred to.