- Tautomeric preferences of phthalones and related compounds
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Multinuclear magnetic resonance and IR spectra prove that although 2-(diacylmethyl)pyridines and 2-(diacylmethyl)quinolines are β-diketones, their proton transfer product present in chloroform solution is not ketoenol but enaminone (earlier opinions were contradictory). Quinoline derivatives are less zwitterionic by character than the respective pyridyl congeners. The β-diketone form itself may also be rarely present in the solution. X-ray data show that 2-(2(1H)-pyridinylidene)-1H-indene-1,3(2H)-dione, i.e., enaminone tautomer of 2-(pyridin-2-yl)-2H-indene-1,3-dione, is also the only form present in crystal. Ab initio calculations show that the enaminone is usually more stable than other tautomeric forms. Values of geometry based aromaticity index HOMA (harmonic oscillator model of aromaticity) confirm that the zwitterionic structure really contributes to the enaminone forms detected.
- Dobosz, Robert,Kolehmainen, Erkki,Valkonen, Arto,O?mia?owski, Borys,Gawinecki, Ryszard
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p. 9172 - 9178
(2008/03/11)
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- Synthesis and pharmacological evaluation of 2-(2 and 4- pyridinyl)indane-1,3-diones and structuraly related compounds exerting potential anti-inflammatory and antitumoral activities
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Our on going work in the series of enamido-diketones issued from 2- azaarylindane-1,3-diones led us to synthesize and experiment N and C2- substituted derivatives of 2-(2 and 4-pyridinyl)indane-1,3-diones as well as of structurally related compounds resulting from the replacement of pyridine by quinoline and benzimidazole. Pharmacological evaluation of their anti- inflammatory activity (by inhibition of carrageenan foot edema) and their anticoagulant activity (by prothombin assay) led to the conclusion of the possibility of achieving a selective antiinflammatory effect. It has been previously established that anticoagulants are liable to exert a protective effect in the development of cancer metastasis. Nevertheless none of the six experimented 2-(pyridin-2-yl)indane-1,3-diones extended survival time of mice treated by P388 lymphocytic leukemia.
- Robert-Piessard,Leblois,Courant,Baut,Petit
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p. 160 - 168
(2007/10/03)
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- β-Diceto enamines heterocycliques: 1. Indanediones-1,3 substituees en 2 par un heterocycle azote
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The condensation of methylated N-heterocycles and especially monomethyl- and polymethylpyridines on phthalic anhydrides leads to 2-aryl-1,3-indanediones.The 3-alkylidenylphthalides formed in an intermediary state have been isolated.The influence of solvents and temperature on the velocity and yield of formation of 2-(2- and 4-pyridyl)-1,3-indandiones has been studied.The ir and nmr spectra confirm that these compounds exist under a β-diketoenamine form resonating with a betaine form.
- Ploquin, J.,Sparfel, L.,Baut, G. Le,Floc'h, R.,Letourneux, Y.
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p. 961 - 973
(2007/10/02)
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