Cycloadditions of 3-Amino-2H-1,4-oxazin-2-ones with Olefins: Generation of 5,6-Dihydro-2-oxo-2H-pyran-6-carbonitriles.
摘要:
The Diels-Alder adducts from the reaction of 3-amino-2H-1,4-oxazin-2-ones 1b-d with olefins in toluene at reflux, undergo ring transformations yielding previously unknown 5,6-dihydro-2-oxo-2H-pyran-6-carbonitriles 3. In some cases the latter are converted into 5-amino-2,4-pentadienenitriles 4. A plausible mechanism is proposed.