GB328357A - Manufacture of polymethine dyestuffs - Google Patents

Abstract

328,357. Kuhn, R., and Winterstein, A. Feb. 13, 1929. Samples furnished. Cyclammonium polymethine dyes are prepared by condensing with formic acid or a formate, a methylene base of a cyclic ammonium salt having an active methyl group in the a- or gamma-position. Instead of the methylene base, a salt thereof with an organic acid may be used. By this process polymethine dyestuffs substituted in the 7: 7<1>- positions can be obtained. Thus formic acid or formates can be condensed with the methylene bases of compounds having the general formula : in which X is a divalent residue such as -CH2-, - S-, or -CH=CH-; Y is an acid radicle; z is a substituent such as CH3, halogen or alkoxy and R is an alkyl group. According to examples : (1) the crude methylene base, corresponding to the methyl iodide of #-naphtho quinaldine obtained by extracting ether, after the addition of caustic soda lye to an acetone solution of the quinaldinium salt, is condensed in the presence of acetic anhydride with formic acid, whereby 1 : 1<1>- dimethylstreptomonovinylene - 2 : 2<1>-# : #<1>-naphthoquinocyanineacetate is produced. Instead of the methylene base of the methyliodide of #- naphthoquinaldine, the bases corresponding to the methyl iodides of a-naphthoquinaldine, quinaldine, 8-chlorquinaldine, 4-carboxyquinaldinemethylester, 8-methylquinaldine, 8-methoxyquinaldine, 8-ethoxy quinaldine, 2: 3:-31-trimethylindolenine, and 9-methylacridine may be used; (2) 1-methyl-2-methylenebenzthiazoline is condensed with formic acid in the presence of acetic anhydride to give 1: 1<1>-dimethylstreptomonovinylene-2: 2<1>-thiocyanine, and 1: 3: 3: 7-tetramethyl-2-methyleneindolene are condensed with formic acid to give 1 : 1<1> : 3: 3: 3<1> : 3<1> : 7: 7'- octa- and 1 : 1<1> : 3 : 3 : 3<1> : 3<1> : 4: 4<1> : 7 : 7<1>-decamethylstreptomonovinylene-2: 2<1>-indocyanine; (3) the chloride of 1: 1<1>: 3 : 3 : 3<1> : 3<1>-hexa-methyl streptomonovinylene-2 : 21-indocyanine is obtained bv reacting formic acid with a mixture of the methyliodide of 2: 3: 3 : trimethylindolenine and the corresponding base; (4) 1 : 2 : 3 : 3-tetramethyl indoleninium trichloracetate (obtained from the corresponding methylene base by treatment with chloracetic acid in alcoholic solution) is dissolved in acetic anhydride and treated with formic acid. 1 : 3 : 3 : 7-Tetra- and 1 : 3: 3 : 4: 7-pentamethyl-2-methylencindolins are prepared from o-toluidine and p-xylidine by forming the corresponding 2-methyl indol (by condensing the tolyl and xylyl hydrazines with acetone and closing the ring) and subsequently treating with methyl iodide; the 2-methylene bases are liberated by treating the resulting cylammonium iodides with alkali. 8-Ethoxyquinaldine is prepared by reacting ophenetidine with paraformaldehyde in the presence of hydrochloric acid. Specification 232,740 is referred to.