Patent GB-596990-A (GB)
Title: Photographic filter and anti-halation layers
IPC: G03C1/83
Filed: 1945-05-17
Abstract: Azo dyes derived from hydroxy aza-indolizine are prepared by diazotizing an amine, coupling with a b -keto ester and condensing with an aminotriazole or aminotetrazole.  The amine may be sulphanilic acid, 1-naphthylamine-5-sulphonic acid, diaminotoluene sulphonic acid, nitraniline sulphonic acid, 1-amino-2-naphthol-4-sulphonic acid, 1-naphthylamine-5 : 7-disulphonic acid, 1-naphthylamine-4-sulphonic acid, 1-naphthylamine-3 : 6 : 8-trisulphonic acid, 2-naphthylamine - 6 - sulphonic acid, or arsanilic acid.  The b -keto ester may be acetoacetic, benzoylacetic, or p-nitrobenzoylacetic ester.  The aminotriazole may be 4-amino-, 3-amino-or 3-amino-5-methyl-1 : 2 : 4 - triazole and the aminotetrazole 5 - aminotetrazole.  The condensation may be carried out in glacial acetic acid.  6 - (5 : 7 - Disulphonaphthalene - 1 - azo) - 7 - hydroxy - 5 - methyl - 1 : 3 : 4 - triazaindolizine is prepared by coupling diazotized 1-naphthylamine-5 : 7-disulphonic acid with acetoacetic ester in alkaline solution and refluxing the product with 3-amino-1 : 2 : 4-triazle in glacial acetic acid.  5-(3 : 5-Dicarboxybenzene-1-azo)-4-hydroxy - 6 - methyl - 2 : 3 : 7 - triazaindolizine, 5 : 51 - (1 - methyl - 4 - sulpho - 2 : 6 - disazo) - bis - (4 - hydroxy - 6 - methyl - 2 : 3 : 7 - triazaindolizine), 6 - (4 - sulphobenzene - 1 - azo) - 7 - hydroxy - 5 - phenyl-1 : 3 : 4-triazaindolizine, 6-(5-sulphonaphthalene-1-azo)-7-hydroxy-2 : 5-dimethyl-1 : 3 : 4-triazaindolizine, 6 - (3 : 5 - dicarboxybenzene - 1 - azo) - 7 - hydroxy - 5 - methyl - 1 : 2 : 3 : 4 - tetrazaindolizine, 5 - (7 - sulphonaphthalene - 1 - azo) - 4 - hydroxy - 6 - methyl - 2 : 3 : 7 - triazaindolizine, 5 - (4 - sulphobenzene - 1 - azo) - 4 - hydroxy - 6 - p - nitrophenyl - 2 : 3 : 7-triazaindolizine, 6-(2-hydroxy-4-sulphonaphthalene - 1 - azo)-7-hydroxy-5-methyl-1 : 3 : 4-triazaindolizine, 6 - (4 - arsinylbenzene - 1 - azo) - 7 - hydroxy - 5 - phenyl - 1 : 3 : 4 - triazaindolizine, 6-(5-sulphonaphthalene-1-azo)-7-hydroxy-5-butyl-1 : 3 : 4 p  - triazaindolizine, 6 - (2 - sulpho - 4 - nitrobenzene - 1 - azo) - 7 - hydroxy - 5 - methyl - 1 : 3 : 4 - triazaindolizine and 6 - (2 - sulpho - 4 - nitrobenzene-1-azo)-7-hydroxy-2 : 5-dimethyl-1 : 3 : 4-triazaindolizine are similarly prepared. 6-(2-Sulpho-4-aminobenzene-1-azo)-7-hydroxy-5-methyl-1 : 3 : 4-triazaindolizine is prepared by reducing 6-(2-sulpho-4-nitrobenzene - 1 - azo) - 7 - hydroxy - 5 - methyl - 1 : 3 : 4 - triazaindolizine with ammonium sulphide.  6 - (2 - Sulpho - 4 - aminobenzene - 1 - azo) - 7 - hydroxy - 2 : 5 - dimethyl-1 : 3 : 4-triazaindolizine is similarly prepared.  6 -(2 - Sulpho - 4 - (1 - hydroxy - 4 : 8 - disulphonaphthalene-2-azo)-benzene-1-azo)-7-hydrox-5-methyl-1 : 3 : 4-triazaindolizine is prepared by coupling 1 - naphthol - 4 : 8 - disulphonic acid in alkaline solution with diazotized 6-(2-sulpho-4-aminobenzene - 1 - azo) - 7 - hydroxy - 5 - methyl - 1 : 3 : 4 - triazaindolizine.  6 - (2 - Sulpho - 4 - (2 - hydroxy - 3 : 6 - disulphonaphthalene - 1 - azo) - benzene-1-azo)-7-hydroxy-2 : 5-dimethyl-1 : 3 : 4-triazaindolizine is similarly prepared.  Nitro and nitroso dyes derived from hydroxyazaindolizines are prepared by condensing aminotriazoles or aminotetrazoles with the appropriate nitro or nitroso substituted benzoylacetic ester. 5-(4-Nitro-2-sulphophenyl)-7-hydroxy - 1 : 3 : 4 - triazaindolizine may be so prepared.