2-N-Imidazolyl- and 2-N-pyrazolyl-1,3-indandiones

It was shown by spectroscopic methods that 2-N-imidazolyl-, 2-N-(N-methylimidazolyl)-, and 2-N-(N-methylpyrazolyl)-1,3-indandiones exist in the form of inner salts, whereas 2-N-pyrazolyl-1,3-indandione exists in the form of an enol with an intramolecular hydrogen bond.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1082–1085, August, 1982.     

Intramolecular C-H...O hydrogen bonding in 2-(N-pyridinia)indane-1,3-dione betaines

The existence of an intramolecular C-H...O hydrogen bond between the protons of the pyridinium ring and the oxygen atoms of the phthaloyl part of the molecule in 2-(N-pyridinia)-indane-1,3-dione betaines and their aza analogs was proved by their PMR spectra. This sort of intramolecular hydrogen bond is absent in pyridinium betaines of cyclohexane-1,3-dione and acetoacetic and malonic esters.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 379–383, March, 1979.     

An unusual reaction of 2-(2-pyridylcarbonyl)- and 2-(2-quinolylcarbonyl)benzoyl chlorides with p-nitroaniline

In the reaction of 2-(2-pyridylcarbonyl)benzoyl chloride, which exists in the form of 6,11-dioxo-6,11dihydrobenzo[b]quinolizinium chloride, with p-nitroaniline, 2-(4-nitrophenylimino)-6, 11-dihydro-2H-benzo-[b]quinolizine-6, I I -dione is unexpectedly formed. When it reacts with water or methanol there is an opening of the quinolizine ring and aromatization of the quinoid fragment with the formation of 2-[4-(4nitrophenylamino)-2-pyridylcarbonyl]benzoic acid or its methyl ester. Under the action of antimony pentachloride, 2- 2-quinolylcarbonyl)benzoylchloride-3 (2-quinolyl)-3-chloro- 1, 3-dihydrobenzo[c]furan-1 -one -is converted to 3-(2-quinolyl)-1,3-dihydrobenzo[c]furan-1-on-3-ylium hexachlorantimonate, which undergoes isomerizing recyclization upon heating to 7,12-dioxo-7,12-dihydrobenzo[b/ hexachloroantimonate. The latter enters into an analogous reaction with p-nitroaniline, thereby forming 5-(4-nitrophenylimino)-7,12-dihydro-5H-dibenzo[b,f]quinolizine-7,2-dione.Riga Technical University, Riga LV-1048. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 938–944, July, 1995. Original article submitted May 31, 1995.     

Comparative study of ring-chain isomeric transitions of 2-cyano-substituted benzamides and benzenesulfamides

The rate constants of cyclization and the constant of ring-chain equilibrium of N-isopropyl-2-cyano-substituted benzamide and benzamide and benzenesulfamide by the methods of PMR and IR spectroscopy, and it was shown that in the transition from 2-cyanobenzamides to 2-cyanobenzenesulfamides a sharp destabilization of the cyclic isomeric form is observed; however, the cyclization of 2-cyanobenzenesulfamides proceeds at a higher rate than the cyclization of 2-cyanobenzamides.