The reaction of an aromatic heterocycle with a proton is called a protonation. One of articles about this theory is 《Heterocyclic N-oxides. III. 8-Hydroxyquinoline N-oxide》. Authors are Ramaiah, K.; Srinivasan, V. R..The article about the compound:8-Hydroxyquinoline 1-oxidecas:1127-45-3,SMILESS:OC1=CC=CC2=CC=C[N+]([O-])=C12).Synthetic Route of C9H7NO2. Through the article, more information about this compound (cas:1127-45-3) is conveyed.
cf. CA 57, 6761f. Unlike 8-hydroxyquinoline (I), the title compound (II) shows no OH stretching at 3400 or 3660 cm.-1, Badger and Moritz (CA 53, 11382g). The broad medium-intensity band of II at 2857-2440 cm.-1 is independent of concentration and is interpreted as evidence of strong intramol. H bonding involving the O-H and N-O groups. Preliminary study by the method of Irving, et al. (CA 43, 8941i) with 23 cations indicates that II chelates more selectively than I. The results at pH 5.2, 8.4, and 12.4 are tabulated. II is conveniently prepared in fair yield by heating (water bath, 65-75°) 14.5 g. I in 30 ml. glacial HOAc with 10 ml. 30% H2O2. At intervals of 1 hr. a total of 30 ml. more of H2O2 was added in 3 equal increments. The mixture was concentrated in vacuo, made alk. with saturated aqueous Na2CO3, and left overnight after addition of 60 ml. CHCl3. Unreacted I was removed by steam distillation of the mixture after filtration, drying and removal of CHCl3 by distillation Hot filtration of the aqueous residue gave on cooling 5.96 g. yellow needles of II, m. 139°.
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Quinoxaline – Wikipedia,
Quinoxaline | C8H6N2 | ChemSpider