Hetarenes with a bridge nitrogen atom. 6. Ambident properties of the oxazolo[3,2-<i>a</i>]pyridinium nucleus in reactions with nucleophiles: Prediction and experiment

Abstract

We have studied the problem of ambident opening of five-membered and six-membered rings of the heteroaromatic oxazolo[3,2-a]pyridinium cation. A quantum chemical SINDO1 calculation of the energies of isomeric adducts of this cation with nucleophiles predicts preferential formation of the C₍₉₎-adduct in the case of OH and SH ions with opening of the oxazole fragment, while for nitrogen-containing nucleophiles (NH₂, NMe₂) attack at the C₍₅₎ atom is also likely with opening of the pyridine fragment. We have experimentally observed that this cation undergoes opening of the five-membered ring in reaction with NaSH, opening of the six-membered ring in reaction with piperidine, and opening of both rings in reaction with ammonia.

How to Cite
Babaev, E. V.; Pasichnichenko, K. Y.; Maiboroda, D. A. Chem. Heterocycl. Compd. 1997, 33, 338. [Khim. Geterotsikl. Soedin. 1997, 397.]

For this article in the English edition, see DOI https://doi.org/10.1007/BF02253115