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"Theoretical Investigation on the Reactivity of
6-amino-3-methylpyrimidin- 4(3H)-ones Towards DMAD, Tandem Diels-Alder
Retro Diels-Alder (DA/RDA) Reaction." Cobo, J., Melguizo, M., Nogueras, M.,
Sanchez, A., Dobado, J.A. and Nonella, M.Tetrahedron 52, 1996, 13721-13732. Abstract: The reactivity of 6-aminopyrimidin-4(3H)-ones towards DMAD is successfully explained by theoretical investigation (PM3 semiempirical methods). All the PM3 results ( activation energies (AE) for the transition states and the heat of formation (DH) for the products) support our previous experimental work [J. Cobo et all. Synlett. 1993, 4, 297-299; Tetrahedron 1994, 50, 10345-10354]. In those reactions two main products were obtained: the pyridine derivatives 5 as major ones, which are formed by a tandem DA/RDA reaction with extrusion of the methylisocyanate fragment; and 5-ethenylpyrimidin-4(3H)-ones 10 as minor ones, which arised from a Michael addition, being in competition with the above normal DA. BMO authors (in alphabetic order): Marco Nonella |