1427-07-2Relevant articles and documents
Base promoted peroxide systems for the efficient synthesis of nitroarenes and benzamides
Gupta, Sampa,Ansari, Alisha,Sashidhara, Koneni V.
supporting information, (2019/09/07)
A useful and efficient approach for the synthesis of nitroarenes from several aromatic amines (including heterocycles) using peroxide and base has been developed. This oxidative reaction is very easy to handle and afforded the products in good yields. Formation of benzamides from benzylamine was also successfully carried out with this metal-free catalytic system in good to excellent yields.
Fluorination of aromatic compounds with xenon difluoride in the presence of boron trifluoride etherate
Fedorov,Zubarev,Mortikov, V. Yu.,Rodinovskaya,Shestopalov
, p. 1049 - 1052 (2016/02/09)
Fluorination of benzene with the XeF2 - BF3?Et2O system in acetonitrile at low temperatures affords fluorobenzene in 18% yield, the conversion of benzene being 92%. The rest products are di-, tri-, tetra-, and polyphenyls with different fluorination pattern. Toluene and chloro- and bromobenzenes are fluorinated predominantly at the ortho and para positions. Fluorination of 4-nitroanisole affords 2-fluoro-4-nitroanisole in 73% yield.
Studying regioisomer formation in the pd-catalyzed fluorination of aryl triflates by deuterium labeling
Milner, Phillip J.,Kinzel, Tom,Zhang, Yong,Buchwald, Stephen L.
supporting information, p. 15757 - 15766 (2015/02/02)
Isotopic labeling has been used to determine that a portion of the desired product in the Pd-catalyzed fluorination of electron-rich, non-ortho-substituted aryl triflates results from direct C-F cross-coupling. In some cases, formation of a Pd-aryne intermediate is responsible for producing undesired regioisomers. The generation of the Pd-aryne intermediate occurs primarily via ortho-deprotonation of a L·Pd(Ar)OTf (L = biaryl monophosphine) species by CsF and thus competes directly with the transmetalation step of the catalytic cycle. Deuterium labeling studies were conducted with a variety of aryl triflates.
A novel improvement in ArLPdF catalytic fluorination of aromatic compounds
Samant, Bhupesh S.,Bhagwat, Sunil S.
experimental part, p. 191 - 194 (2012/01/05)
In this study, we used reverse micellar medium for overcoming the disadvantages of ArLMF catalytic fluorination of aromatic compounds. It not only enhanced the fluorination rate, but also widened the scope of reaction for bromoaromatics with electron donating and withdrawing functionalities at ortho position. Various bromoaromatic compounds were fluorinated using the biarylphosphine ligand i.e. cyclohexyl BrettPhos ligand, along with [cinnamylPdCl]2, and CsF as the fluoride source in reverse micellar media. The anisotropic palisade layer of reverse micelles provided the active site for reaction. The most crucial factor in the critical reductive elimination step could be the spatial orientation of ArLPdF complex in the palisade layer; forming ArF as the final product in high yield with excellent selectivity.
Formation of arf from lpdar(f): catalytic conversion of aryl triflates to aryl fluorides
Watson, Donald A.,Su, Mingjuan,Teverovskiy, Georgiy,Zhang, Yong,Garcia-Fortanet, Jorge,Kinzel, Tom,Buchwaldf, Stephen L.
scheme or table, p. 1661 - 1664 (2010/06/16)
Despite increasing pharmaceutical importance, fluorinated aromatic organic molecules remain difficult to synthesize. Present methods require either harsh reaction conditions or highly specialized reagents, making the preparation of complex fluoroarenes ch
Bis(dealkoxycarbonylation) of nitroarylmalonates: A facile entry to alkylated nitroaromatics
Gurjar,Reddy,Murugaiah,Murugaiah
, p. 1659 - 1661 (2007/10/03)
A simple approach to alkylated nitroaromatics from substituted nitroaryl malonic esters by double decarboxylation is detailed.
Elemental fluorine Part 12. Fluorination of 1,4-disubstituted aromatic compounds
Chambers, Richard D.,Hutchinson, John,Sparrowhawk, Matthew E.,Sandford, Graham,Moilliet, John S.,Thomson, Julie
, p. 169 - 173 (2007/10/03)
Direct fluorination of a series of 1,4-disubstituted benzene derivatives in acid reaction media at convenient temperature leads, in many cases, to selectively fluorinated aromatic products in preparatively useful conversions and yields.
Fluorination process
-
, (2008/06/13)
According to the present invention there is provided a process for the selective introduction of one or more fluorine atoms into a disubstituted aromatic compound in an acid medium with fluorine gas characterized in that the acid medium has a dielectric constant of at least 20 and a pH of less than 3. The present process provides a cost effective means of selectively introducing one or more fluorine atoms into an aromatic compound in good overall yield.
A novel method for the nitration of simple aromatic compounds
Smith, Keith,Musson, Adam,DeBoos, Gareth A.
, p. 8448 - 8454 (2007/10/03)
Simple aromatic compounds such as benzene, alkylbenzenes, halogenobenzenes, and some disubstituted benzenes are nitrated in excellent yields with high regioselectivity under mild conditions using zeolite β as a catalyst and a stoichiometric quantity of nitric acid and acetic anhydride. The zeolite can be recycled, and the only byproduct is acetic acid, which can be separated easily from the nitration product by distillation; the process is inexpensive and represents an attractive method for the clean synthesis of a range of nitroaromatic compounds. For example, nitration of toluene gives a quantitative yield of mononitrotoluenes, of which 79% is 4-nitrotoluene; fluorobenzene gives a quantitative yield of mononitro compounds, of which 94% is 4-nitrofluorobenzene; and 2-fluorotoluene gives a 96% yield of mononitro products, of which 90% is the 5-nitro isomer and 10% is the 4-nitro isomer.
Sulfonation and ipso Substitution in the Course of Nitration of Aromatic Compounds in the System N2O5-SO3-H2O
Dimiev,Kargin
, p. 1831 - 1836 (2007/10/03)
The nitration of halobenzenes and halotoluenes in the system N2O5-SO3-H2O in the areas of low water contents are accompanied by sulfonation and ipso substitution. The occurence of the latter processes is the chief reason for the observed change in the isomeric distribution and the fall in the yield of nitro products with increasing degree of dehydration of the nitrating mixture. A procedure is proposed which allows quantitative estimation of the contributions of the sulfonation and ipso substitution to the final isomeric distribution of nitro products and calculation of values that characterize the true selectivity of nitration.
