Patent GB-1059256-A (GB)
Title: Fluorescent, practically colourless, benzimidazole and benzoxazole derivatives
IPC: D06L4/60
Filed: 1965-12-31
Abstract: Optical brightening agents which are fluorescent, practically colourless benzimidazole and benzoxazole derivatives, containing no nitro group, of the general Formula (I) <FORM:1059256/C2/1> wherein A denotes the residual members of an aromatic hydrocarbon ring system condensed with the heterocyclic ring in the manner indicated, X represents an oxygen atom or the group <FORM:1059256/C2/2> R being a hydrogen atom or an unsubstituted or substituted alkyl, alkenyl, cycloalkyl or aralkyl radical,and Ar represents an aromatic hydrocarbon radical, and of the corresponding quaternary salts of the Formula (II) <FORM:1059256/C2/3> wherein R1 represents an unsubstituted or subtuted alkyl, alkenyl, cycloalkyl or aralkyl radical and Andenotes an anion. The compounds of Formula (I) may be prepared by (1) condensing a furan-2-carboxylic acid with an optionally substituted aryl radical at its 5-position or a functional derivative thereof with a primary arylamine having a hydroxyl group or an amino group with at least one hydrogen atom in the position adjacent to the primary amino group, or (2) condensing a furan-2-aldehyde with an optionally substituted aryl radical at its 5-position with a primary aryl-amine having a hydroxyl group or an amino group with at least one hydrogen atom in the position adjacent to the primary amino group to form an azomethine of the Formula (III) <FORM:1059256/C2/4> and cyclizing said azomethine with an oxidizing agent in manner known per se.  Compounds of Formula (II) may be prepared by treating compounds of Formula (I) with quaternizing agents. Compounds of Formula (I) and (II) may be obtained via the 5-aryl-furan-2-aldehyde condensation with the aryl-amine when one or both components contain a nitro group provided that the nitro group(s) in the benzimidazole or benzoxazole products are reduced to amino groups, which are preferably subsequently acylated. Benzimidazole compounds of Formula (I) wherein X is <FORM:1059256/C2/5> and R is alkyl, alkenyl, cycloalkyl or aralkyl can be obtained from those benzimidazole compounds of Formula (I) wherein X is -NH-by reaction with alkylating agents and subsequently reacting the reaction products with alkaline-reacting agents.ALSO:Spinning and casting compositions which serve for the production of artificial fibres, threads, sheets and other shaped products contain, as optical brightener, a fluorescent, practically colourless benzimidazole or benzoxazole derivative, containing no nitro group, of the formula <FORM:1059256/C3/1> wherein A denotes the residual members of an aromatic hydrocarbon ring system, which may contain substituents, condensed with the heterocyclic ring in the manner indicated, X represents an oxygen atom or the grouping <FORM:1059256/C3/2> R being a hydrogen atom or an unsubstituted or substituted alkyl, alkenyl, cycloalkyl or aralkyl radical, and Ar represents an aromatic hydrocarbon radical which may contain substituents, or the quaternary salts thereof of the formula <FORM:1059256/C3/3> wherein R1 represents a substituted or unsubstituted alkyl, alkenyl, cycloalkyl or aralkyl radical and Andenotes an anion.  Examples refer to polyacrylonitrile compositions (Ex. 7) and polyvinyl chloride compositions (Ex. 15).ALSO:Fibres, threads, sheets and other shaped products are optically brightened with agents which are fluorescent, practically colourless benzimidazole and benzoxazole derivatives, containing no nitro group, of the general formula <FORM:1059256/D1-D2/1> wherein A denotes the residual members of an aromatic hydrocarbon ring system which may contain substituents condensed with the heterocyclic ring in the manner indicated, X represents an oxygen atom or the grouping <FORM:1059256/D1-D2/2> R being a hydrogen atom or an unsubstituted or substituted alkyl, alkenyl, cycloalkyl or aralkyl radical, and Ar represents an aromatic hydrocarbon radical which may contain substituents, or the quaternary salts thereof of the general formula <FORM:1059256/D1-D2/3> wherein R1 represents a substituted or unsubstituted alkyl, alkenyl, cycloalkyl or aralkyl radical and Ari denotes an anion. Specified fibres &c. are wool, cellulose, cellulose esters, polyamides, polyurethanes, polyesters, polyvinyl chloride, polyvinyl acetate, polystyrene, and polyacrylonitrile.  The agents can be applied as, for example, aqueous solutions or dispersions or organic solutions and can be used in admixture with detergents.