A. Corsaro et al., 1,3-dipolar cycloaddition reactions of benzonitrile oxide to 2(1H)-pyrazinone and its N- and O-methyl derivatives, HETEROCYCLE, 53(1), 2000, pp. 69-80
2(1H)-Pyrazinone, which is in equilibrium with 2-pyrazinol, reacts with ben
zonitrile oxide (BNO) affording the N-1-adduct with a 67% yield, while 2-me
thoxypyrazine gives two methoxypyrazinones (ca. 3%) and a biscycloadduct to
gether with its degradation product, which derive from the two unisolable m
onocycloadducts to the C=N-4 double bond. N-Methylpyrazinone gives only the
degradation product (3.4%) of the initial monocycloadduct of BNO to C=N-4
doable bond.