Patent GB-967503-A (GB)
Title: Improvements relating to photographic colour formers
IPC: C07D231/52
Filed: 1961-04-11
Abstract: The invention comprises compounds of the general formula: <FORM:0967503/C1/1> wherein R is a monovalent cyclic radical of aromatic character directly connected to the intracyclic nitrogen atom by an intracyclic carbon atom and R1 is hydrogen, alkyl of 1-4 carbon atoms, or chlorine, the compound 1-phenyl -3- methacrylamido -5- pyraxolone being disclaimed.  The radical R is preferably an aryl (e.g. phenyl, m-tolyl, p-methoxyphenyl, p-chlorophenyl, p-bromophenyl, p-cyanophenyl, p-nitrophenyl, or naphthyl), 2-benzoxazolyl, 2-benzthiazolyl, 2-, 3-, or 4-pyridyl, or 2-quinolyl radical.  The compounds are prepared by the reaction of a 1-substituted -3- amino -5- pyrazolone with an acid halide of acrylic or an a -substituted acrylic acid.  Example 1 describes the reaction of ethyl cyanoacetate with p-bromophenylhydrazine to give 1-(p-bromophenyl) -3- amino -5- pyraxolone which is then reacted with methacrylyl chloride to give 1-(p-bromophenyl) -3- methacrylamido -5- pyraxolone.  Specifications 786,344 and 967,504 are referred to.ALSO:Copolymers are made from (a) a compound of the general formula: <FORM:0967503/C3/1> wherein R is a monovalent cyclic radical of aromatic character directly connected to the intracyclic nitrogen atom by an intracyclic carbon atom and R1 is hydrogen, alkyl of 1-4 carbon atoms, or chlorine, other than the compound 1-phenyl -3- methacrylamido -5- pyrazolone, and (b) a solid or liquid monomer containing at least one terminal ethylenic group and a group ionisable in aqueous solution at pH 3-11, and/or (c) a solid or liquid monomer containing at least one terminal ethylenic group but which is non-ionisable in aqueous solution at pH 3-11, both the monomers (b) and (c) being capable of forming high polymers in the presence of an addition polymerization initiator. Monomers (b) specified are acrylic acid, and its a -methyl, -ethyl, -n-propyl, -nbutyl and -chloro derivatives, styrene sulphonic acid and its alkali metal, ammonium and amine salts, sodium vinyl sulphonate, 2 and 4-vinylpyridine and N-vinyl -2- pyrrolidone acid salts and quaternary salts, and quaternary salts of diethylaminoethyl acrylate and methacrylate. Monomers (c) specified are styrene, esters of monohydric C1- 8 alcohols with acrylic, a -alkylacryli and a -chloroacrylic acids, acrylamide, ethacrylamide, acrylonitrile, methacrylonitrile, vinyl ethyl ether, ureidoethyl vinyl ether and methyl vinyl ketone. Examples describe the copolymerization in the presence of a , a 1-azo-bis-(isobutyronitrile) of 1-(p-bromophenyl)-3-methacrylamido -5-pyraxolone and the following monomers in various proportions: acrylamide + acrylic acid; methyl methacrylate + acrylic acid; acrylic acid; acrylic acid + N-vinyl -2-pyrrolidone; acrylic acid + styrene; methyl methacrylate. Dilute solutions of the copolymers in aqueous sodium carbonate form magenta dyes upon the addition of potassium persulphate as oxidant and N,N-diethyl -pphenylendiamine as developing agent. The copolymers are used as colour-formers in photographic emulsions (see Division G2). Specifications 786,344 and 967,504 are referred to.