332-33-2Relevant academic research and scientific papers
Cu(II)-Catalyzed Ortho-C-H Nitration of Aryl Ureas by C-H Functionalization
Wang, Chun-Meng,Tang, Kai-Xiang,Gao, Tian-Hong,Chen, Lin,Sun, Li-Ping
, p. 8315 - 8321 (2018/07/15)
A novel protocol for the aromatic ortho C-H nitration of aryl ureas with Fe(NO3)3·9H2O is developed. The reaction utilizes CuCl2·2H2O as catalyst and p-TSA as additive, showing good functional group tolerance and furnishing the desired products in moderate to excellent yields.
One-pot synthesis of 2,3-difunctionalized indoles: Via Rh(III)-catalyzed carbenoid insertion C-H activation/cyclization
Lv, Honggui,Shi, Jingjing,Wu, Bo,Guo, Yujuan,Huang, Junjun,Yi, Wei
supporting information, p. 8054 - 8058 (2017/10/13)
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.
Oxidative fluorination of N-arylsulfonamides
Buckingham, Faye,Calderwood, Samuel,Checa, Bego?a,Keller, Thomas,Tredwell, Matthew,Collier, Thomas Lee,Newington, Ian M.,Bhalla, Rajiv,Glaser, Matthias,Gouverneur, Véronique
supporting information, p. 33 - 39 (2015/09/22)
We report a late stage oxidative nucleophilic fluorination of N-arylsulfonamides, a class of compounds so far not considered as precursors to 4-fluorophenyl sulfonamides. By installing a para-positioned tert-butyl substituent on the aniline, oxidative fluorination takes place regioselectively in the presence of HF·pyridine and PIDA. This methodology has been shown to give good yields for a variety of ortho- and meta-functionalised N-arylsulfonamides and has been adapted for radiofluorination to give 4-[18F]fluorophenyl sulfonamides under carrier added conditions.
Merging C-H activation and alkene difunctionalization at room temperature: A palladium-catalyzed divergent synthesis of indoles and indolines
Manna, Manash Kumar,Hossian, Asik,Jana, Ranjan
supporting information, p. 672 - 675 (2015/03/04)
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.
Copper-catalyzed mild nitration of protected anilines
Hernando, Elier,Castillo, Rafael R.,Rodríguez, Nuria,G?mez Arrayás, Ram?n,Carretero, Juan C.
supporting information, p. 13854 - 13859 (2016/02/18)
A practical copper-catalyzed direct nitration of protected anilines, by using one equivalent of nitric acid as the nitrating agent, has been developed. This procedure features mild reaction conditions, wide structural scope (with regard to both N-protecting group and arene substitution), and high functional-group tolerance. Dinitration with two equivalents of nitric acid is also feasible. Practical and reliable: A Cu-catalyzed selective nitration of para- and ortho-substituted aniline derivatives by using one equivalent of HNO3 has been developed that produces water as the only stoichiometric byproduct (see scheme; PG=protecting group). This method is compatible with strongly electron-deficient substrates, enabling dinitration (by using 2.0 equiv of HNO3). This method allows for a rapid access to relevant nitrogen-containing heterocyclic architectures.
Rhodium(iii)-catalysed aerobic synthesis of highly functionalized indoles from N-arylurea under mild conditions through C-H activation
Kathiravan, Subban,Nicholls, Ian A.
supporting information, p. 14964 - 14967 (2014/12/11)
A Rh(iii) catalysed amino arylation of alkynes using copper as the terminal oxidant for regeneration of the catalytically active species under aerobic conditions is described. This novel C-H activation reaction was applied to the synthesis of a wide range of substituted indoles from N-arylureas.
