Patent GB-821843-A (GB)
Title: New oxdiazole compounds and process for their manufacture
IPC: C07D413/14
Filed: 1956-02-14
Abstract: Fluorescent brightening agents (free from hydroxyl groups) of the formula <PICT:0821843/III/1> where A is the residue of an aromatic nucleus, R1 is a p-phenylene group which may be substituted and X is a carbocyclic, heterocyclic or aryl-vinyl group which may be substituted, are used in combination with washing agents.  The latter may be soaps; salts of sulphonated 2-(higher alkyl)-benzimidazoles, of higher alkyl esters of 4-sulphophthalic acid, of fatty alcohol sulphates, alkylaryl sulphonic acids or condensation products of higher fatty acids with hydroxy- or amino-sulphonic acids; polyglycol derivatives of higher alcohols, alkylphenols or fatty amines; sulphite waste liquor; formaldehyde-naphthalene-sulphonic acid condensation products; or inorganic washing agents.  There may also be present alkali metal carbonates, phosphates, polyphosphates, silicates, perborates or percarbonates.  The components can be mixed or ground together, with preferably one in the molten or dissolved state.  The fluorescent brightening agents can also be added to oils and fats.ALSO:Fluorescent brightening agents (free from hydroxyl groups) for textile fibres, yarns or materials are of the formula <FORM:0821843/IV(c)/1> where A is the residue of an aromatic nucleus, R1 is a p-phenylene group which may be substituted and X is a carbocyclic, heterocyclic or aryl-vinyl group which may be substituted.  The compounds can be added to dyebaths, bleaching baths, finishing baths (e.g. crease-proofing), printing, discharge or reserve pastes or washing preparations, or may be used as after-treatment of dyeings or prints.  The textiles may be of wool, silk, cotton, hemp, flax, linen, jute, ramie, regenerated cellulose, cellulose esters (e.g. acetate or butyrate) or polyamides.  In examples: (1) undyed cotton yarn is washed with the compound of the formula <FORM:0821843/IV(c)/2> 2) cellulosic material is bleached in a hypochlorite bath containing the compound of (1) (3) undyed polyamide material is treated with formic acid and the compound of the formula <FORM:0821843/IV(c)/3> (4) undyed cotton is washed with sodium 2-heptadecyl - N - benzyl - benzimidazole disulphonate and the compound of the formula  <FORM:0821843/IV(c)/4> Azo dyes which are intermediates for the preparation of the above fluorescent brightening agents (see Group IV (b)) are made by coupling arylamines (preferably naphthylamines and preferably sulphonated) with (a) diazonium compounds from p-aminobenzoic acid or a 2-(p-aminophenyl - 1 : 3 : 4 - oxadiazole substituted in the 5-position by a carbocyclic, heterocyclic or aryl-vinyl group, or (b) bis-diazonium compounds from 2 : 5-bis-(p-aminophenyl) - 1 : 3 : 4 - oxadiazole, or 2 : 21 - bis - (p - aminophenyl) - 5 : 51 - di - (1 : 3 : 4 - oxadiazolyl), or 1 : 4-bis-[2 : 21-bis-(p - aminophenyl) - 5 : 51 - di - (1 : 3 : 4 - oxadiazolyl)]-benzene.  The products in the last two cases are of the formula <FORM:0821843/IV(c)/5> where A is an aromatic residue, R1 and R2 are p-phenylene residues and n is 1 or 2. In all the above any of the benzene rings may be substituted, e.g. by methyl, methoxy, chloro or sulphonic acid.  Specific monoazo dyes prepared are p-aminobenzoic acid -->2-naphthylamine-5 : 7-disulphonic acid, and 2-(p-aminophenyl)-5 - (p - chlorophenyl) - 1 : 3 : 4 - oxadiazole --> 2 - naphthylamine.  Specific disazo dyes prepared are 2 : 5 - bis - (p - aminophenyl) - 1 : 3 : 4 - oxadiazole --> m - phenylene diamine or 2 - naphthylamine - 5 : 7 - disulphonic acid. Other coupling components are mentioned.ALSO:Fluorescent brightening agents (free from hydroxyl groups) of the formula <FORM:0821843/IV (a)/1> where A is the residue of an aromatic nucleus, R1 is a p-phenylene group which may be substituted and X is a carbocyclic, heterocyclic or aryl-vinyl group which may be substituted, are added to spinning solutions of viscose, polyamides or acetyl-cellulose or to carbohydrates such as starch.ALSO:The invention comprises hydroxyl-free compounds of the formula <FORM:0821843/IV (a)/1> where A is an aromatic nucleus, R1 is p-phenylene, which may be substituted, and X is a carbocyclic, heterocyclic or aryl-vinyl group which may be substituted.  There are included compounds of the formula <FORM:0821843/IV (a)/2> where R2 is, e.g., p-phenylene, m and n are 1 or 2, and R3 is as for X, particularly those in which R3 is of the type <FORM:0821843/IV (a)/3> The compounds are made ultimately from a p-amino-benzoic acid or functional derivative thereof by (1) diazotizing and coupling with an arylamine to give an azo dye which is oxidized to a triazole; and (2) condensing with hydrazine, a carboxylic acid hydrazide or a dicarboxylic acid hydrazide to form the oxadiazole ring, these steps being performed in any order.  There may be used instead of the diazotizable amino group another group (e.g. nitro) which is converted to amino after the formation of the oxadiazole ring. Sulphonation may be carried out, preferably by using oleum as the ring-closing agent.  The residue A may be a benzene ring (optionally substituted by amino, methyl or methoxy) but is preferably a sulphonated naphthalene ring.  The other benzene rings may be substituted by methyl, methoxy or chlorine.  The products are fluorescent brightening agents for a large number of materials, including gelatine.  In examples: (1) the dyestuff - p - carboxy - benzene - azo - 2 - naphthylamine - 5 : 7 - disulphonic acid is oxidized to the triazole and condensed with hydrazine to give 2 : 5-diphenyl-1 : 3 : 4-oxadiazole p-substituted in both benzene rings by disulphonaphthotriazolyl; (2) 2 : 5-bis-(p-aminophenyl)-1 : 3 : 4-oxadiazole (see Specification 746,047) is tetrazotized, coupled with 2-naphthylamine-5 : 7-disulphonic acid and the resulting dyestuff oxidized to the same product as in (1); (3) 2-[p (51 : 71 - disulphonaphthotriazolyl) - phenyl] - 5 - sulphophenyl - 1 : 3 : 4 - oxadiazole is made from p - (51 : 71 - disulphonaphthotriazolyl) - benzoic acid, benzoylhydrazine and oleum; (4) a bis-compound analogous to (3) is obtained by using terephthaloyl-bis-hydrazine instead of benzoylhydrazine; (5) p-chlorobenzoylhydrazine is condensed with p-nitrobenzoic acid to give 2 - (p - chlorophenyl) - 5 - (p - nitrophenyl)-1 : 3 : 4-oxadiazole, the nitro group reduced to amino, and the product diazotized, coupled with 2-naphthylamine and finally oxidized to 2-(p-chlorophenyl) - 5 - (p - naphthotriazolyl - phenyl)-1 : 3 : 4-oxadiazole; (6) the disazo dyestuff from 2 : 5-bis-(p-aminophenyl)-1 : 3 : 4-triazole and m-phenylenediamine is oxidized to 2 : 5 - bis - [p - (5 - aminobenzotriazolyl) - phenyl] - 1 : 3 : 4 - oxadiazole, which can be solubilized by heating with butane sultone.  Other starting materials are mentioned.ALSO:Hydroxyl-free fluorescent brightening compounds of the formula <FORM:0821843/VI/1> where A is the residue of an aromatic nucleus, R1 is a p-phenylene group which may be substituted and X is a carbocyclic, heterocyclic or aryl-vinyl group which may be substituted, are used to improve the optical properties of edible carbohydrates (e.g. flour, sugar) and cosmetic preparations, e.g. tooth, hair or sunburn preparations.