申请人:MINNESOTA MINING AND MANUFACTURING COMPANY
公开号:EP0339869A2
公开(公告)日:1989-11-02
This invention relates to phenazine dyes, and more particularly, to phenazine dyes suitable as intermediates for leuco phenazine dyes. Essentially all of the phenazine dyes capable of providing red, orange, and magenta hues have unsubstituted amine groups at the 3- or 7-position, or both. The presence of unsubstituted amine groups at the 3- or 7-positions, or both, does not allow one to employ a simple, direct method to reduce and acylate the dye at the 10-position without also acylating the dye at the 3- or 7-position or both. In a reduced leuco dye which contains acyl groups at the 10-position as well as the 3- and/or 7-positions, reoxidation under normal conditions removes only the acyl group at the 10-position, which will yield a dye form having different absorption properties from that of the original, unreduced dye containing the unsubstituted amine group. Therefore, phenazine dyes known in the art, such as phenosafranine, which are red, magenta, and the like, do not provide the original dye color upon reduction acylation and reoxidation. Although phenazine dyes containing substituents at the 3- and 7-positions are well known, essentially all of them provide turquoise or blue colors. This invention provides 3,7-diamino phenazine dyes having at least one electron-withdrawing substituent on at least one of the groups attached to the amine groups at the 3- and 7-positions, provided that the algebraic sum of the para position Hammett sigma (σp) values for the groups attached to the nitrogen atoms of the amine groups at the 3- and 7-positions is more positive than about -0.6. The group containing the electron-withdrawing substituent can be selected from: (1) a substituted alkyl group, and (2) a substituted aryl group.
本发明涉及吩嗪染料,更具体地说,涉及适用于作为月桂吩嗪染料中间体的吩嗪染料。基本上所有能够提供红色、橙色和品红色的酚嗪染料都在 3-位或 7-位或两者上具有未取代的胺基团。由于在 3 位或 7 位或这两个位置上都存在未取代的胺基团,因此无法采用简单直接的方法在 10 位上还原和酰化染料,而不同时在 3 位或 7 位或这两个位置上酰化染料。还原型白兰地染料在 10 位以及 3 位和/或 7 位上都含有酰基,在正常条件下进行再氧化时,只去除 10 位上的酰基,这样得到的染料形态与含有未取代胺基团的原始未还原型染料的吸收特性不同。因此,本领域已知的酚嗪染料,如红色、品红色等的酚萘胺,在还原酰化和再氧化后不能提供原来的染料颜色。虽然在 3 位和 7 位上含有取代基的酚嗪染料是众所周知的,但它们基本上都能提供青绿色或蓝色。本发明提供的 3,7-二氨基酚嗪染料在 3-位和 7-位氨基上连接的至少一个基团上具有至少一个吸电子取代基,条件是 3-位和 7-位氨基的氮原子上连接的基团的对位 Hammett sigma(σp)值的代数和大于约-0.6。含有抽电子取代基的基团可选自:(1) 取代的烷基;(2) 取代的芳基。