- Facile synthesis of 3,5-diaryl-1,2,4-triazoles via copper-catalyzed domino nucleophilic substitution/oxidative cyclization using amidines or imidates as substrates
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Two methods for the synthesis of 3,5-diaryl-1,2,4-triazoles, both domino reactions, are reported. The first procedure, the Cu(OTf)2-catalyzed reaction between two amidines using NaHCO3 as a base, 1,10-phenanthroline as an additive and K3[Fe(CN)6]/ atmospheric oxygen as the oxidant, delivers 3,5-diaryl-1,2,4-triazoles with yields up to 68%. The second procedure for the synthesis of 3,5-diaryl-1,2,4- triazoles with yields up to 64% rests on the Cu(OTf)2-catalyzed reaction between two imidates and ammonium carbonate. This method features the formation of three bonds in a single synthetic step.
- Sudheendran, Kavitha,Schmidt, Dietmar,Frey, Wolfgang,Conrad, Jürgen,Beifuss, Uwe
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p. 1635 - 1645
(2014/02/14)
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- Preparation of amidines from amidoximes via transfer hydrogenation
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Amidoximes are reduced into amidine using triethyl silane and PdCl 2 in acetic acid. Copyright
- Mahajan, Umesh S.,Godinde, Rupesh R.,Mandhare
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experimental part
p. 2195 - 2199
(2011/06/27)
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- Pyrimidine derivatives and liquid crystal compositions including same
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2-phenyl-5-(4'-trans-cyclohexyl) phenyl pyrimidine derivatives represented by the general formula: STR1 wherein R is a straight chain alkyl group having 1 to 10 carbon atoms; X is CN or F; Y is F or H; Z is F or H; and when X is F, at least one of Y and Z is H; and the cyclohexane ring is a trans isomer, exhibiting a nematic phase and having a high nematic phase-isotropic liquid phase transition temperature (N-I Point) and large positive dielectric constant anisotropy (Δε). The pyrimidine derivatives may be included in liquid crystal compositions for improved display devices having a wide temperature range, including a high N-I point, a low threshold voltage and a low driving voltage.
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- Preparation of Triazolopyrimidines as Potential Antiasthma Agents
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With the use of the human basophil histamine release assay, 5-aryl-2-aminotriazolopyrimidines were found to be active as mediator release inhibitors.These compounds were prepared by reacting arylamidines with sodium ethyl formylacetate or with ethyl propiolate to give pyrimidinones.Treatment with phosphorus oxychloride gave a chloropyrimidine, which was converted to a hydrazinopyrimidine with hydrazine.Cyclization, using cyanogen bromide, gave the triazolopyrimidines, after a Dimroth rearrangement.Following a structure-activity evaluation, the5--2-amino (8-10), 5-(3-bromophenyl)-2-amino (8-13), 5--2-amino (8-11), and 5-(4-pyridinyl)-2-amino (6-7) compounds were found to have the best activity.They were chosen for further pharmacological and toxicological study.
- Medwid, Jeffrey B.,Paul, Rolf,Baker, Jannie S.,Brockman, John A.,Du, Mila T.,et al.
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p. 1230 - 1241
(2007/10/02)
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