RING-CHAIN TAUTOMERISM OF 2-ARYL-SUBSTITUTED IMIDAZOLIDINES

N-Methyl-, N-ethyl-, N-(n-propyl)-, N-(iso-propyl)- and N-phenyl-2-ary limidazolidines proved to be ring-chain tautomeric mixtures in CDCl3. The ratios of the open and ring forms in the tautomeric equilibria of these compounds is described by the equation log K-x = p sigma(+) + lo g Kx-H, used earlier for the ring-chain equilibria of saturated 2-aryl -1,3-O,N-heterocycles. These ale the first examples among 2-arylimidaz olidines of ring-chain tautomeric processes characterized by a Hammett -type correlation. (C) 1998 Elsevier Science Ltd. All rights reserved.