DOTTADs – readily made novel metal ligands with multivariant functionality – trans-DOTTADs and semi-DOTTADs
作者:Andrea Arany、Otto Meth-Cohn、István Berhés、Miklós Nyerges
DOI:10.1039/b303675h
日期:——
Two new ligand systems related to the previously described DOTTADs have been generated in a simple one step reaction. The first, trans-DOTTADs, were formed by Vilsmeier formylation (followed by cyclisation and N-demethylation) of 2,6-dimethyl-3,5-pyrazine-dicarboxylic acid, to give the novel bis-pyridinopyrazine dialdehyde ligands. The corresponding pyrazine diester, reacted similarly to an intermediate iminium ion stage, which gave trans-DOTTAD imines on work-up with amines. The treatment of Hantzsch ester with two equivalents of benzaldehyde gave 7-phenyl-2-(2-phenylethenyl)-7,8-dihydropyrano[4,3-b]pyridin-5-one-3-carboxylic acid. This product underwent similar cyclisation with Vilsmeier reagents to give, for example, 6-methyl-2-(2-phenylethenyl)-8-(phenylhydroxymethyl)-6H-[1,6]naphthyridin-5-one-3-carboxylic acid, an example of a semi-DOTTAD.
我们通过简单的一步反应生成了与之前描述的 DOTTADs 相关的两种新配体系统。第一种反式 DOTTADs 是通过 2,6-二甲基-3,5-吡嗪二羧酸的 Vilsmeier 甲酰化反应(随后是环化和 N-去甲基化反应)形成的,从而得到新型双吡啶吡嗪二醛配体。相应的吡嗪二酯也会发生类似的反应,生成中间亚胺离子阶段,在与胺反应后生成反式-DOTTAD 亚胺。用两个当量的苯甲醛处理 Hantzsch 酯,可得到 7-苯基-2-(2-苯基乙烯基)-7,8-二氢吡喃并[4,3-b]吡啶-5-酮-3-羧酸。该产物与 Vilsmeier 试剂进行类似的环化反应,可得到例如 6-甲基-2-(2-苯基乙烯基)-8-(苯基羟甲基)-6H-[1,6]萘啶-5-酮-3-羧酸,这是半 DOTTAD 的一个例子。