| 摘要 |
1,181,951. Methine dyes. YORKSHIRE DYEWARE & CHEMICAL CO. Ltd. 29 Jan., 1969 [3 Feb., 1968], No, 5569/68. Heading C4P. The invention relates to water-soluble methine dyes of the formula wherein R 1 is alkyl, R 2 is alkyl, R 3 is alkyl or benzyl, R 4 is alkyl, aryl, carbamoyl or carboxylic acid ester, R 5 is alkyl or benzyl, R 6 is alkyl or aryl, X is an anion and the ring A may be substituted for example by Cl, Br, carboalkoxy, NO 2 , alkyl or acetyl. The aryl group R 6 may contain a chloro group. The dyes are prepared (1) by alkylating a base of formula prepared by the usual condensation methods or (ii) by reacting a compound of formula with an appropriate pyrazolone substituted in the 2-position in the presence of an acid. Double salts may be prepared using ZnCl 2 .
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