Patent GB-701237-A (GB)
Title: Improvements in or relating to the production and use of acetals containing cyanoacetyl groups
IPC: G03C7/327
Filed: 1951-09-20
Abstract: The invention comprises acetals of aldehydes of the formula OHC.(CH2)n.Q.R:COCH2CN where R is a divalent carbocyclic or heterocyclic aromatic radical attached to the C and Q groupings by carbon atoms forming part of the ring system, Q is an oxygen or sulphur atom and n is 1-6, with an alcohol which is preferably a hydroxyl polymer which is water soluble to hydrophilic in character and contains a large number of recurring intralinear -CH2-CHOH-groups.  Suitably the polymeric alcohol is a polyvinyl alcohol containing 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 of the type described above and 0.1 per cent.-5 per cent. of which are acetalized with an aldehyde containing a sulphonic or carboxylic acid group, e.g. o-sulphobenzaldehyde.  The group R is preferably a hydrocarbon nucleus such as benzene or a heterocyclic nucleus containing an oxygen sulphur or nitrogen hetero atom.  The acetals are prepared by reacting an acetal of a monomeric alcohol such as an alkanol or an alkane 1:2 or 1:3 diol and an aldehyde of the above general formula (see Group IV(b)) with a hydroxyl polymer in the presence of an acid substance as a catalyst to give acetal interchange.  In examples polyvinyl alcohol is reacted partly with o-sulphobenzaldehyde and partly with (1) (p-cyanoacetylphenoxy) acetaldehyde dimethyl acetal; (3) (p-cyanoacetylphenylmercapto) acetaldehyde dimethyl acetal; (5) b -(p-cyanoacetylphenoxy) propionaldehyde diethyl acetal; (6) b -(p-cyanoacetylphenoxy)-propionaldehyde ethylene glycol acetal and (7) b -(cyanoacetyl-3-methyl-6-benzofuranoxy)-propionaldehyde ethylene glycol acetal, giving in each case the corresponding mixed acetal of polyvinyl alcohol.ALSO:The invention comprises acetals of alcohols with aldehydes of the formula OHC.(CH2)n.Q.R.CO.CH2CN. where R is a divalent carbocyclic or heterocyclic aromatic radical attached to the C and Q groupings by carbon atoms forming part of the ring system, Q is an oxygen or sulphur atom, n is 1-6, and the alcohol is a monomeric alkanol of 1 to 4 carbon atoms, or a monomeric 1:2 or 1:3 alkane diol of 2-4 carbon atoms, or a hydroxyl polymer which is water soluble or hydrophilic and contains a large number of recurring intralinear -CH2-CHOH- groups.  In the latter cases the acetal group forms a cyclic structure.  The group R may be a hydrocarbon nucleus e.g. benzene or a heterocyclic nucleus containing an oxygen, sulphur or nitrogen hetero atom.  The invention also comprises a process for the production of the acetals which comprises reacting a compound of the formula <FORM:0701237/IV (b)/1> where A1 is an alkyl group, A is the residue of an alkane 1:2 or 1:3 diol and R1 is an aromatic cyclic radical substituted by a carbalkoxy group, with acetonitrile in the presence of an alkaline compound as a condensing agent.  In examples there are prepared by the above process, (1) and (2) the dimethyl acetal and ethylene glycol acetal of (p-cyanoacetylphenoxy)-acetaldehyde; (3) (p-cyanoacetylphenylmercapto)-acetaldehyde dimethyl acetal; (4) p (2-cyanoacetyl - 3 - naphthoxy) - acetaldehyde dimethyl acetal; (5) b -(p-cyanoacetylphenoxy)-propionaldehyde diethyl acetal; (6) b -(p-cyanoacetylphenoxy - propionaldehyde) ethylene glycol acetal and (7) b -(2-cyanoacetyl -3-methyl-6-benzofuranoxy) - propionaldehyde ethylene glycol acetal.  Many other carbocyclic and heterocyclic cyanoacetyl-aryl groups which may be attached to the oxy or thio groups are specified.  Carbalkoxy - aryloxyaldehyde acetals.  The acetals of carbalkoxyaryloxy (or carbalkoxyarylthio) - substituted aliphatic aldehydes are prepared by reacting an alkali metal salt of a carbalkoxy-substituted nuclear compound having a hydroxy or thio group attached to carbon of the aromatic nucleus with an acetal of a w-halogenated aliphatic aldehyde.  In examples (p-carbethoxyphenoxy)-acetaldehyde dimethyl acetal; (p-carbethoxyphenoxy)-acetaldehyde ethylene glycol acetal; (p-carbethoxyphenylmercapto) acetaldehyde dimethyl acetal; (2 - carbethoxy - 3 - naphthoxy) acetaldehyde dimethyl acetal; b -(p-carbethoxyphenoxy) - propionaldehyde - diethyl acetal; b  - (p - carbethoxyphenoxy) propionaldehyde ethylene glycol acetal and b -(2-carbethoxy-3-methyl - 6 - benzofuranoxy) propionaldehyde ethylene glycol acetal are made in this way.