ULTRAVIOLET SPECTRA OF 2-PHENYL-4- AND 2-PHENYL-5-AZAINDAN-1, 3-DIONES

Abstract

The UV spectra of 2-phenyl-4-azaindan-1, 3-dione (I), 2-phenyl-5-azaindan-1, 3-dione (II), and their N-methylbetaines are investigated. 2×10⁻⁵ M aqueous alcoholic solutions of 2-phenyl-4-azaindan-1, 3-dione (I) contain the anionic form (IA), and in solutions of 2-phenyl-5-azaindan-1, 3-dione (II) the betaine form (IIB) is also in equilibrium with the anion (IIA). Solutions of I and II in 0.1 M sulfuric acid are characterized by a wide and rather intense absorption band at about 500 mμ, indicating the presence of a betaine form (IB and IIB). In 2M hydrochloric acid solution 2-phenylazaindan-1, 3-diones and their N-methylbetaines (III and IV) are protonated at the oxygen atom, giving the enol forms of the N-protonated or corresponding N-methylated 2-phenylazaindandiones.

Authors: L. E. Neiland, G. Ya. Vanag.

English Translation in Chemistry of Heterocyclic Compounds, 1965, 1 (1), pp 62-65

http://link.springer.com/article/10.1007/BF01168923