- Sulfonium Salts as Alkylating Agents for Palladium-Catalyzed Direct Ortho Alkylation of Anilides and Aromatic Ureas
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A novel method for the ortho alkylation of acetanilide and aromatic urea derivatives via C-H activation was developed. Alkyl dibenzothiophenium salts are considered to be new reagents for the palladium-catalyzed C-H activation reaction, which enables the transfer of methyl and other alkyl groups from the sulfonium salt to the aniline derivatives under mild catalytic conditions.
- Simkó, Dániel Cs.,Elekes, Péter,Pázmándi, Vivien,Novák, Zoltán
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supporting information
p. 676 - 679
(2018/02/09)
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- One-pot synthesis of 2,3-difunctionalized indoles: Via Rh(III)-catalyzed carbenoid insertion C-H activation/cyclization
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Reported herein is the first Rh(iii)-catalyzed carbenoid insertion C-H activation/cyclization of N-arylureas and α-diazo β-keto esters. The redox-neutral reaction has the following features: good to excellent yields, broad substrate/functional group tolerance, exclusive regioselectivity, and no need for additional oxidants or additives, which render this methodology as a more efficient and versatile alternative to the existing methods for the synthesis of 2,3-difunctionalized indoles.
- Lv, Honggui,Shi, Jingjing,Wu, Bo,Guo, Yujuan,Huang, Junjun,Yi, Wei
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supporting information
p. 8054 - 8058
(2017/10/13)
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- Merging C-H activation and alkene difunctionalization at room temperature: A palladium-catalyzed divergent synthesis of indoles and indolines
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A palladium-catalyzed 1,2-carboamination through C-H activation at room temperature is reported for the synthesis of 2-arylindoles, and indolines from readily available, inexpensive aryl ureas and vinyl arenes. The reaction initiates with a urea-directed electrophilic ortho palladation, alkene insertion, and ?2-hydride elimination sequences to provide the Fujiwara-Moritani arylation product. Subsequently, aza-Wacker cyclization, and ?2-hydride elimination provide the 2-arylindoles in high yields. Intercepting the common -alkyl-Pd intermediate, corresponding indolines are also achieved. The indoline formation is attributed to the generation of stabilized, cationic -benzyl-Pd species to suppress ?2-hydride elimination.
- Manna, Manash Kumar,Hossian, Asik,Jana, Ranjan
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supporting information
p. 672 - 675
(2015/03/04)
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- Comparative catalytic C-H vs. C-Si activation of arenes with Pd complexes directed by urea or amide groups
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Analysis of regiocontrol in Pd-catalysed C-H activation leads to observations of aryltrimethylsilyl activation and to superior results with urea-based substrates.
- Rauf, Waqar,Thompson, Amber L.,Brown, John M.
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supporting information; experimental part
p. 3874 - 3876
(2010/01/06)
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- THERMAL DECOMPOSITION OF SUBSTITUTED UREAS
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The thermal dissociation of N,N'-diaryl- and N,N-dimethyl-N'-aryl-ureas was investigated under isothermal conditions in absence of solvent.In the case of N,N-dimethyl-N'-arylureas enthalpies of reaction were determined, and their relation to Hammett ? constants was shown.
- Chimishkyan, A. L.,Svetlova, L. P.,Leonova, T. V.,Gluyaev, N. D.
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p. 1317 - 1320
(2007/10/02)
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- INFRARED SPECTROSCOPIC AND CONFORMATIONAL STUDIES OF TRISUBSTITUTED UREAS CONTAINING CHLOROPHENYL GROUPS
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The IR spectra, in the ν(N-H) region, of trisubstituted ureas R2UPhCl and RPhUPhCl containing a chlorophenyl group have been studied in order to examine the effects of the introduced chlorine atom.The out-trans-cis isomerism about the NH-CO rotational axis is discussed in reation to steric effect of the R2 group, Ph-Ph interaction and inter- and intra-molecular hydrogen bonding.In dilute solution, R2UPhCl exists in the trans or the out form, and RPhUPhCl in the cis form. o-Chlorophenyl derivatives show a monomeric ν(N-H) band at a wavenumber lower than that of the other derivatives and no associated ν(N-H) bands in concentrated or even in saturated solutions.Some of the derivatives are found to be in the same form in the solid state as in solution due to the retention of intra-molecular NH...Cl hydrogen bonding.
- Mido, Yoshiyuki,Furusawa, Chizuko
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- Process for the preparation of trisubstituted ureas
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The present invention provides a process for preparing a trisubstituted urea of the general formula: in which R is a substituted or unsubstituted mono-, di- or polyvalent aromatic radical, R' is a substituted or unsubstituted monovalent aliphatic or aromatic radical and R is a substituted or unsubstituted monovalent aliphatic radical or R' and R together represent a substituted or unsubstituted divalent radical in which at least one of the two carbon atoms adjoining the nitrogen atom of the urea is aliphatic, and n is an integer, wherein an aromatic nitrocompound of the general formula:--R(NO2)n or an aromatic nitrosocompound of the general formula:--R(NO)n is allowed to react with a secondary ammonium N,N-disubstituted thiolcarbamate of the general formula: or with a mixture of a secondary amine of the general formula:--R'R NH and carbon monoxide and sulphur, carbon monoxide and hydrogen sulphide, or carbonyl sulphide, or with a mixture of a secondary ammonium sulphide or hydrosulphide of the general formula: or and carbon monoxide.
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