v-Triazolines.: Part 42.: Study on the reactivity of 4,5-dihydro-1-(6-methyl-2-oxo-2H-pyran-4-yl)-5-morpholino-v-triazoles.: Synthetic approach to pyrano[4,3-b]pyrrol-4(1H)-ones

Pyrolysis of 4-aryl-5-morpholino-4,5-dihydrotriazoles 3 affords two products: pyrano[4,3-b]pyrrol-4(1H)-ones 4 and arylacetamidines 5. The reaction mechanism of this transformation is discussed and reaction conditions optimized to enhance the formation of pyrrole-fused pyran-2-one derivatives 4. 2-Aminoaziridines are considered to be key intermediates in this transformation.