Nucleophilic additions 2,3-dichloro-5,6-dicyano- 1,4-benzoquinone

The electrophilic character of 1,2,4-triazines allows their introduction into different other systems. Thus, calix[4]arenes 12 were modified at the meso-carbon atom with a 1,2,4-triazine ring by nucleophilic addition of a calrx-arene lithium derivative to 3,6-diphenyl-l,2,4-triazine 13 with formation of o-adduct 14 which was then oxidized with DDQ (2,3-dichloro-5,6-dicyano-1,4-benzoquinone) giving an aromatic product 15 (13MHC308). 

Oxidation with 2,3-dichloro-5,6-dicyano-l,4-benzoquinone (DDQ) of the thiourea 51, derived from dopamine, gave the 1,3-benzothiazepine 53 in quantitative yield via a facile J-based nucleophilic intramolecular addition to the intermediate o-quinone 52 (Equation 9) <2005OBC2387>. 

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