REACTION OF 2-BROMO 2-ALKENOIC CARBONYL-COMPOUNDS WITH AMIDINES - EXPERIMENTAL AND THEORETICAL (PM3) STUDIES OF THE MECHANISM OF HETEROCYCLIZATION INTO DIHYDROIMIDAZOLE AND PYRIMIDIN-4(3H)-ONE
P. Friant et al., REACTION OF 2-BROMO 2-ALKENOIC CARBONYL-COMPOUNDS WITH AMIDINES - EXPERIMENTAL AND THEORETICAL (PM3) STUDIES OF THE MECHANISM OF HETEROCYCLIZATION INTO DIHYDROIMIDAZOLE AND PYRIMIDIN-4(3H)-ONE, Perkin transactions. 2, (6), 1993, pp. 1123-1127
Different pathways have been considered to describe heterocyclisation
between monosubstituted or unsubstituted amidines and 2-bromo 2-alkeno
ic carbonyl compounds, giving pyrimidin-4(3H)-one or dihydroimidazole
heterocycles. Semi-empirical calculations (PM3) have been carried out
on the reactants and intermediates. The transition states have been an
alysed. From both thermodynamic and kinetic arguments, it appears that
a mechanism involving a pyrimidinone intermediate is more probable th
an one in which the intermediate is an aziridine. Solvent effects have
been estimated and they do not seem to modify substantially these con
clusions.