Oxidative reactions of azines. 12. Dehydrogenation and oxidation of 2-methyl-9-phenyl-2,3-dihydro-1H-2-azafluorene

Synthesis and molecular structure of 4-nitro-9-phenyl-1H-and 9-hydroxy-3-oxo-9-phenyl-2,3-dihydro-9H-indeno-[2,1-c]pyridines and 3,7-diphenyl-3a, 4,5,6-tetrahydroindeno[2,1-c]isoxazolo[5,4-d]pyridine

“…Yield was 0.38 g (17%). In mp (143-145°C), 1 H NMR, mass, and IR spectra substance 3 was identical with the substance isolated and described previously in [5]. Methyl-3,7-diphenyl-3a,4,5,6-tetrahydroindeno[2,1-c]isoxazolo[5,4-d]pyridine (5).…”

“…It is necessary to mention that compound 3 has melting point, IR, 1 H NMR, and mass spectra identical to those of the substance obtained previously by us by the oxidation of the initial 1a with manganese dioxide at room temperature [5]. With the aim of finally establishing its structure and stereochemical features, an X-ray structural analysis was carried out on compound 3 (Fig.…”

“…As a continuation of the systematic investigation of the chemistry [4,5] and biological activity [6,7] of indenopyridine derivatives we have in the present work introduced the problem of studying the direction of the conversions of N-alkyl-9-phenyl-2,3-dihydro-1H-indeno[2,1-c]pyridines 1a,b on interacting them with sodium nitrite in acid medium, and also with benzohydroxymoyl chloride in the presence of base. The importance of the functionalization of these close precursors of the antiallergic agent thephorin [1] is evident, although it is impossible to consider the target chemical modification of the latter a very simple problem, if the extremely significant chemical lability of the precursors is taken into consideration [5]. First of all, on studying the reaction between sodium nitrite and indenopyridines 1a,b it was established that the main products are the 4-nitro derivatives 2a,b, isolated by column chromatography as garnet-red crystals in yields of 50 and 49% respectively.…”

Oxidation of heterocyclic compounds by manganese dioxide (Review)*

“…Thus, boiling of the substituted tetrahydropyridines 31 with MnO 2 in aqueous acetone leads to the formation of the α-pyridones 32 (yields 21-57%) [38]. During the action of MnO 2 on 2,3-dihydro-1H-2-azafluorene 33 its heterocyclic fragment is oxidized to a lactam fragment, which is stabilized as a result of migration of the double bond with the formation of the azafluorene derivative 34 (yield 20%) [39,40]. The quaternary salts of di-and tricyclic heteroaromatic compounds containing a pyridinium ring are oxidized by MnO 2 to the corresponding N-substituted derivatives of annulated α-or γ-pyridones.…”