- Synthesis of trifluoromethylated analogues of 4,5-dihydroorotic acid
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4-(Trifluoromethyl)pyrimidin-2(1H)-ones react with trimethylsilyl cyanide in the presence of a tertiary amine catalyst to give Michael-like 1,4-conjugate hydrocyanation adducts exclusively at the 3,6-positions. The resulting 2-oxo-6-(trifluoromethyl)- 1,2,3,4-tetrahydropyrimidine-4-carbonitriles have been used to synthesize new trifluoromethylated 4,5-dihydroorotic acid analogues and their esters in racemic as well as enantiopure forms by a chiral auxiliary approach. The orthogonal intramolecular C-F...C=O interaction between the fluorine atom of the CF3 group and the carbon atom of the ester group observed in the crystal state may stabilize the sterically unfavourable conformation of the methyl 2-oxo-6-(trifluoromethyl) hexahydropyrimidine-4-carboxylate molecule with axially oriented substituents.
- Sukach, Volodymyr A.,Resetnic, Anastasia A.,Tkachuk, Viktor M.,Lin, Zhengguo,Kortz, Ulrich,Vovk, Mykhailo V.,R?schenthaler, Gerd-Volker
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- A catalytic oxidation fragrant boron class compound preparing phenol method (by machine translation)
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The invention discloses a method for catalytic oxidation of phenolic compounds fragrant boron class compound synthesis method, the flux in the solvent in the aqueous solution, under the action of alkali, adding hydrazine hydrate or acid hydrazides catalyst, catalytic oxidation fragrant boron class compound directly for the preparation of phenolic compound. The invention of the method of preparation of the phenol compound, the catalyst is a cheap hydrazine hydrate or hydrazine compound, the oxidizing agent is atmospheric pressure of air or oxygen, the reaction does not need good and activeness metal catalyst, is extensive and stable substrate, substrate-sensitive functional group compatibility good and wide range of application. In the optimized under the reaction conditions, the yield of the target product separation up to 99%. (by machine translation)
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Paragraph 0073; 0125; 0126
(2017/08/08)
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- Electron-deficient heteroarenium salts: An organocatalytic tool for activation of hydrogen peroxide in oxidations
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A series of monosubstituted pyrimidinium and pyrazinium triflates and 3,5-disubstituted pyridinium triflates were prepared and tested as simple catalysts of oxidations with hydrogen peroxide, using sulfoxidation as a model reaction. Their catalytic efficiency strongly depends on the type of substituent and is remarkable for derivatives with an electron-withdrawing group, showing reactivity comparable to that of flavinium salts which are the prominent organocatalysts for oxygenations. Because of their high stability and good accessibility, 4-(trifluoromethyl)pyrimidinium and 3,5-dinitropyridinium triflates are the catalysts of choice and were shown to catalyze oxidation of aliphatic and aromatic sulfides to sulfoxides, giving quantitative conversions, high preparative yields and excellent chemoselectivity. The high efficiency of electron-poor heteroarenium salts is rationalized by their ability to readily form adducts with nucleophiles, as documented by low pKR+ values (pKR+ red > -0.5 V). Hydrogen peroxide adducts formed in situ during catalytic oxidation act as substrate oxidizing agents. The Gibbs free energies of oxygen transfer from these heterocyclic hydroperoxides to thioanisole, obtained by calculations at the B3LYP/6-311++g(d,p) level, showed that they are much stronger oxidizing agents than alkyl hydroperoxides and in some cases are almost comparable to derivatives of flavin hydroperoxide acting as oxidizing agents in monooxygenases.
- ?turala, Ji?í,Bohá?ová, Soňa,Chudoba, Josef,Metelková, Radka,Cibulka, Radek
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p. 2676 - 2699
(2015/03/18)
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- PROCESS FOR THE SYNTHESIS OF HALOGENATED CYCLIC COMPOUNDS
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Process for the synthesis of halogenated cyclic compounds A process for the manufacture of a cyclic compound of formula (I) wherein R1 is a halogenated alkyl group Z and Y designate independently carbon or a heteroatom A is a linking group between Z and Y comprising 0, 1, 2 or 3 atoms in the cycle which comprises (a) adding an acid halide of formula R1-C (O)-X wherein X = fluorine, chlorine or bromine and R1 has the meaning given above, to a vinyl ether of formula (II) CH2 =CH-OR2 (II) wherein R2 is an alkyl group, an aralkyl group or an aryl group to produce an addition product and (b) said addition product is reacted with a compound of formula (III) Y-A-Z (III), Z, Y and A are as defined above.
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Page/Page column 8
(2010/04/27)
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- 4-TRIFLUOROMETHYLPYRIMIDINES
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It is shown that β-alkoxyvinyl trifluoromethyl ketones are convenient reagents for the synthesis of 4-trifluoromethylpyrimidines that contain a hydrogen atom or hydroxy, mercapto, and amino groups in the 2 position.The NMR, IR, and UV spectra of the synth
- Gerus, I. I.,Vdovenko, S. I.,Gorbunova, M. G.,Kukhar', V. P.
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p. 398 - 406
(2007/10/02)
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