A Comparative Study of Conventional Conditions Versus Microwave Irradiation for the Preparation of Novel 1,2-Dihydro-2-imino-7-methyl-1,6(6H)-naphthyridin-5-ones

摘要

The synthesis of novel 1,6-naphthyridines 6 with potential activity against tuberculosis is described using the reaction sequence 2->4->6. Depending on the ring N-substitution of the 4-alkylamino-6-methyl-2(1H)-pyridones 1 and 2 the electrophilic attack of the Vilsmeier reagent gives rise to the formation of the exocyclic N-formyl derivatives 3 from 1 and the corresponding 3-carbaldehydes 4 from 2.1,2-Dihydro-2-imino-7-methyl-1,6(6H)-naphthyridin-5-ones 6a-j are prepared by the Knoevenagel reaction of 4 with CH-acidic nitriles 5. These reactions are carried out using a comparative study of cinventional conditions(room temperature or reflux)versus microwave irradiation.