Patent GB-705950-A (GB)
Title: Improvements in or relating to acetals containing cyanoacetyl groups and photographic processes using the same
IPC: C07D307/68
Filed: 1951-09-20
Abstract: The invention comprises polymeric acetals of aldehydes of the formula OHC-R-CO-CH2CN where R is a divalent heterocyclic or carbocyclic aromatic radical attached to the -CO and OHC-groupings by carbon atoms forming part of the ring system, with a polymeric polyhydric alcohol, such as polyvinyl alcohol.  Preferably the polyvinyl alcohol chain contains at least 25 hydroxyl groups per 100 carbon atoms in the chain, between 0.75 per cent. and 10 per cent. of which are acetalized by an aldehyde according to the above general formula and 0.1 per cent. to 5 per cent. are acetalized with an aldehyde containing a sulphonic or carboxylic acid group, e.g. o-sulphobenzaldehyde.  Preferably R is a hydrocarbon nucleus such as benzene, or a heterocyclic nucleus containing at least one oxygen, sulphur or nitrogen hetero atom. The acetals are prepared by reacting a monomeric acetal of a cyanoacetylaryl aldehyde (see Group IV (b)), suitably one of the formula <FORM:0705950/IV (a)/1> where A is the residue of a 1:2 or 1:3 diol, with a hydroxyl polymer containing a large number of recurring -CH2-CHOH-groups.  In examples there are prepared the polyvinyl alcohol acetals of (1) 5-cyanoacetyl-2-furaldehyde; (2) 4-cyanoacetylbenzaldehyde; (3) and (4) 2-cyanoacetyl-5-benzofuraldehyde; (5) 2-cyanoacetyl - 3 - methyl - 5 - benzofuraldehyde; (6) 2-cyanoacetyl-3-phenyl-5-benzofuraldehyde and (7) 2-cyanacetyl-3-methyl-naphtho-(2:1-b) furaldehyde.  Many other cyanoacetylaryl groups which may be used are specified.ALSO:The invention comprises acetals derived from alcohols and aldehydes of the formula OHC-R.-CO-CH2-CN. where R is a divalent carbocyclic or heterocyclic aromatic nucleus attached to the CHO and CO groups by carbon atoms forming part of the ring system.  The alcohol is a monomeric alcohol of 1-4 C atoms or preferably a monomeric 1:2 or 1:3 alkane diol of 2-4 C atoms or it may be a polymeric hydroxy compound (see Group IV (a)).  In the latter cases the acetal group has a cyclic structure.  The acetals are prepared by reacting the corresponding acetal of a carboalkoxyaryl aldehyde of the formula OHC-R-COOR1 where R1 is an alkyl group of preferably 1-4 carbon atoms with acetonitrile in the presence of alkali, e.g. sodium methylate. In examples there are prepared by the above process the ethylene glycol acetals of (1) 5-cyanoacetyl-2-furaldehyde; (2) 4-cyanoacetyl benzaldehyde; (3) 2-cyanoacetyl-5-benzofuraldehyde and the dimethyl acetals of (4) 2-cyanoacetyl-5-benzofuraldehyde; (5) 2-cyanoacetyl-3-methyl-5-benzofuraldehyde; (6) 2-cyanoacetyl-3-phenyl-5-benzofuraldehyde; and (7) 2-cyanoacetyl-3-methyl-naphtho-(2:1-b) furaldehyde.  Many other carbocyclic and heterocyclic nucleii which may be attached to the CO and acetal groups are specified.  Acetals of carboalkoxyaryl aldehydes.  The acetals derived from carboalkoxyaryl aldehydes of the formula OHC.R.COOR1 described above are prepared by treating the aldehyde with the corresponding alcohol.  Specified acetals are the ethylene glycol acetals of 5-carbomethoxy-2-furaldehyde; 4-carbomethoxybenzaldehyde and 2-carbomethoxy-5-benzofuraldehyde and the dimethyl acetals of 2-carbomethoxy-5-benzofuraldehyde; 2-carbomethoxy-3-methyl-5 - benzofuraldehyde; 2 - carbomethoxy - 3 - phenyl - 5 - benzofuraldehyde and 2 - carbo methoxy-3-methyl-naphtho-(2:1-b) furaldehyde.  Carboalkoxyaryl aldehydes of the formula OHC.R.COOR1 are prepared by reacting an ester of a halomethylaryl carboxylic acid with 2-nitropropane in the presence of alkali.  The aldehydes specified in the above paragraph are prepared in this way.  Alkyl esters of halomethylaryl carboxylic acids are prepared by halomethylating an alkyl ester of an aromatic carboxylic acid, specifically by treating the ester with paraformaldehyde in the presence of zinc chloride and dry hydrogen chloride in a chlorinated methane solvent or by brominating a methyl aryl carboxylic ester.  Specified halogenated esters are methyl-5-chloromethylfuroate; methyl- 5 -chloromethylbenzofuran-2-carboxylate; methyl-5-chloromethyl-3-methylbenzofuran-2-carboxylate; methyl-5-bromomethyl-3-phenylbenzofuran-2-carboxylate and methyl chloromethyl- 3 -methylnaphtho - (2:1 - b)-furan-2-carboxylate. Methyl-4-bromo-methylbenzoate is prepared by treating p-toluic acid with thionyl chloride, and brominating the resulting p-toluyl chloride and treating with methanol.  Benzofuran-2-carboxylic acids. Ethyl 5-methyl-3-phenylbenzofuran-2-carboxylate is prepared by condensing ethyl-a -chlorobenzoyl acetate with p-cresol.  Methyl 3-methyl-naphtho-(2:1-b) furan-2-carboxylate is prepared by condensing a -chloroacetoacetate with b -naphthol.  The free acid of the former is obtained by hydrolysis.