- Synthesis and electrophilic substitution of pyrido[2,3,4-kl]-acridines
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Several new pyrido[2,3,4-kl]acridines were synthesized by reacting naphthoquinone, juglone or cyclohexan-1,3-dione with β,β'- diaminoketones in a biomimetic reaction. The structure of all new compounds was elucidated by NMR and MS spectroscopy. Electrophi
- Koller, Avi,Rudi, Amira,Garcia Gravalos, Marta,Kashman, Yoel
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p. 300 - 322
(2007/10/03)
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- Nickel catalyzed electrosynthesis of ketones from organic halides and metal carbonyls
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Ketones can be easily obtained by electroreduction in an undivided cell of an organic halide-metal carbonyl mixture using a Ni-bpy catalytic system in DMF (bpy = 2,2'-bipyridine). The process is especially well convenient for primary benzyl and alkyl halides.
- Dolhem,Ocafrain,Nedelec,Troupel
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p. 17089 - 17096
(2007/10/03)
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- Antiviral benzimidazoles
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Certain N-substituted benzimidazoles are disclosed. The compounds are potent antiviral agents. Pharmaceutical formulations containing such compounds and a method of treating viral infections are provided.
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- ELECTROCHEMICAL REDUCTION OF 2,2'-DINITRODIPHENYLMETHANE AND 2,2'-DINITROBENZOPHENONE AT MERCURY ELECTRODES
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The last two compounds in a 5-membered series of aromatic dinitrocompounds are reduced in a completely different manner at mercury electrodes. 2,2'-Dinitrodiphenylmethane (I) - in which a conjugation of both symmetrical moieties is ruled out - is electrolytically reduced in an eight-electron step to a bishydroxylamine this being most stable between pH 4.5 and 5.0.In processing the catholyte increase in concentration of this product leads to its intermolecular disproportionation, resulting in the formation of dibenzo-1,2-diazepine 5-oxide (IV) and2,2'-diaminodiphenylmethane (III). 2,2'-Dinitrobenzophenone (II) reduces at more positive potentials.Its preparative electrolysis in acetonitrile (with 0.1M-N(n-C4H9)4PF6 as supporting electrolyte) the application of which was made necesarry by the low solubility of II in ethanol, proceeds in an anomalous way.In the most positive cathodic wave a radical anion results, the following cathodic wave corresponds to a 6-electron reduction of one nitro group to an amino group while the other nitro group splits off as the anion NO2(-) (this later giving an anodic wave).Its formation has been proved by standard addition in polarography and by a qualitative analytical test.The product which results through this electrode process and a follow-up chemical reaction is acridone.This is turn, reduces in the third, most negative 4-electron wave to dihydroacridine.The comparison of all substances studied in this series reveals that their reducibility decreases with respect to the link X, viz. in the sequence CO > O > S and CH2 > NH.The electrolytical reduction on mercury cathodes occurs in a similar manner with analogues where X=O, S or CH2.Here, the main intermediate is the bis-hydroxylamine the stability of which predetermines the structure of final products.The other group comprises the substances with X=CO and NH.Here the main intermediate is the 2-nitro-2'-amino-diphenyl-X which is formed in a 6-electron process taking place at one of the nitro groups.The follow-up cyclization reaction leading to seven-membered heterocyclic rings located between two benzene nuclei only occurs with analogues of the type X=CH2, O and S.A partial reduction of dinitro compounds of this series has been observed with the analogue containing the NH link although that with X=CO has generally good preconditions for this mechanism.
- Voigtlaender, Rolf,Hlavaty, Jaromir,Volke, Jiri,Bakos, Viktor
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p. 364 - 378
(2007/10/02)
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