2. ν-Triazolines. Part 42.1 Study on the reactivity of 4,5-dihydro-1-(6-methyl-2-oxo-2H-pyran-4-yl)-5-morpholino-ν-triazoles. Synthetic approach to pyrano[4,3-b]pyrrol-4(1H)-ones Emanuela Erba,Donato Pocar,Pasqualina Trimarco J. Chem. Soc. Perkin Trans. 1 2001 1723