- Atom-Economic Silver-Catalyzed Difunctionalization of the Isocyano Group with Cyclic Oximes: Towards Pyrimidinediones
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An unprecedented silver-catalyzed difunctionalization of the isocyano group with cyclic oximes is described. This method allows efficient and atom-economic assembly of a vast array of structurally novel and interesting pyrimidinediones, and tolerates a range of functionalities. The resulting products can be easily converted into some useful compounds. Furthermore, the method can also be applied for the late-stage modification of a few biologically active molecules.
- Liang, Hong-Wen,Yang, Zhen,Jiang, Kun,Ye, Ying,Wei, Ye
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supporting information
p. 5720 - 5724
(2018/04/25)
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- Switchable Synthesis of Pyrroles and Pyrazines via Rh(II)-Catalyzed Reaction of 1,2,3-Triazoles with Isoxazoles: Experimental and DFT Evidence for the 1,4-Diazahexatriene Intermediate
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4-Aminopyrrole-3-carboxylates and pyrazine-2-carboxylates were synthesized from 5-alkoxyisoxazoles and 1-sulfonyl-1,2,3-triazoles by tuning the Rh(II) catalyst and the reaction conditions. The reaction in chloroform at 100 °C under Rh2(OAc)4 catalysis provides 4-aminopyrrole-3-carboxylates in good yields. The use of Rh2(Piv)4 in refluxing toluene results in the formation of 1,2-dihydropyrazine-2-carboxylates as the main products, which can be converted by a one-pot procedure to pyrazine-2-carboxylates by heating with catalytic amounts of TsOH. According to the NMR and DFT investigations of the reaction mechanism, pyrroles and dihydropyrazines are formed, respectively, via 1,5- and 1,6-cyclization of common (5Z)-1,4-diazahexa-1,3,5-triene intermediates. The influence of the nature of the catalyst on the product distribution is rationalized in terms of the Rh-catalyzed isomerization of a pyrrolin-2-ylium-3-aminide zwitterion, the primary product of 1,4-diazahexatriene 1,5-cyclization.
- Rostovskii, Nikolai V.,Ruvinskaya, Julia O.,Novikov, Mikhail S.,Khlebnikov, Alexander F.,Smetanin, Ilia A.,Agafonova, Anastasiya V.
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p. 256 - 268
(2017/04/26)
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- Synthesis of novel isoxazole fused heterocycles
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Condensation of 3-aryl-4-formyl isoxazoles with 1,2-diamines led to the formation of 3-aryl-(6,7-benzo-1,5-heptadiazino)(3,2-d)-isoxazoles or isoxazolo-[5,4-b]-benzodiazepines and 3,10-diaryl-6,7,14,15-tetrhydro-13 H,16H-diisoxazole-(4,5-b;4,5-l)(1,4,8,11)-tetra-aza-cyclo-tetra-deca-4, 14-diones, the novel seven-and 14-membered heterocyclic systems. Similar compounds are of great importance in medicinal chemistry.
- Rajender, P. Sarita,Sridevi,Reddy, K. Kondal
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experimental part
p. 2191 - 2200
(2012/06/16)
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- High-temperature rearrangements of 2-acylisoxazol-5(2H)-ones and related oxazoles
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2-Acyl-3-arylisoxazol-5(2H)-ones give 2-alkyl(aryl)-4-aryloxazoles in good yields at 540°C under flash vacuum pyrolysis conditions, but at higher temperatures the expected oxazoles are accompanied by increasing amounts of isomeric 2,5-disubstituted oxazoles, as well as anilides and decomposition products of the 2,4-disubstituted oxazole. The rearrangement mechanisms have been studied by the use of 13C labelled substrates and p-substituted 3-arylisoxazolones. The 2,5-disubstituted oxazoles are considered to arise from 1H-azirines, and the anilides from the nitrone ketene isomer of the acylisoxazolone.
- Clark, Adrian D.,Ha, Uyen T.,Prager, Rolf H.,Smith, Jason A.
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p. 1029 - 1033
(2007/10/03)
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- Synthesis of 1H-1,5-benzodiazepin-2(3H)-ones from 5(4H)-isoxazolone, a heterocyclic bifunctional C-3 synthon
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Unsubstituted and 7- or 8-substituted 4-aryl-1H-1,5-benzodiazepin-2(3H)-ones 3a-t have been synthesized by the condensation of 3-aryl-5(4H)-isoxazolones 1a-e and parent 4-substituted 1,2-benzenediamines 2a-d under acidic conditions.
- Rao,Reddy,Veeranagaiah
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p. 446 - 448
(2007/10/02)
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