N-oxides and related compounds. Part XXXIV. The tautomerism of some naphtho-and quinolino-furoxans

Abstract

Nuclear magnetic resonance (¹H) at room and elevated temperatures has been used to study the tautomerism of a number of naphtho- and quinolino-furoxans. Free-energy differences between tautomers are, in general, small, while the activation energies for their equilibrations (ca. 20 kcal./mole) are ca. 6 kcal./mole higher than those of benzofuroxans. An attempt to prepare naphtho[2,3-c]furoxan was unsuccessful.