REACTIONS OF 1, 2, 4-TRIAZINES WITH 4, 5-DIMETHYL-1, 2-DEHYDROBENZENE

Abstract

Arynes are known intermediates in reactions with azaheterocycles. However, the reactions of fist ones with 1, 2, 4-trriazines are not well studied so far. In continuation of our studies on interactions of 3, 5-substituted-1, 2, 4-triazines with arynes we wish to report herein our results observed in reactions of these heterocycles with 4, 5-dimethyl-1, 2-dehydrobenzene. This dimethyl-aryne was generated in situ from the corresponding anthranilic acid as precursor by the reaction with iso-Amyl-ONO in 1, 4-dioxane and the following reaction with 5, 6-diaryl-3-(pyridyl-2)-1, 2, 4-trazines 1 in refluxed toluene for 2 hours. In all the cases the reaction afforded the domino-products, namely pyrido[1, 2-a]indoles 2, as major products, while the “classical” ID Diels-Alder products, such as iso-quinolines 3, were obtained only in trace amounts.