4549-33-1Relevant articles and documents
Thiourea-Mediated Halogenation of Alcohols
Mohite, Amar R.,Phatake, Ravindra S.,Dubey, Pooja,Agbaria, Mohamed,Shames, Alexander I.,Lemcoff, N. Gabriel,Reany, Ofer
, p. 12901 - 12911 (2020/11/26)
The halogenation of alcohols under mild conditions expedited by the presence of substoichiometric amounts of thiourea additives is presented. The amount of thiourea added dictates the pathway of the reaction, which may diverge from the desired halogenation reaction toward oxidation of the alcohol, in the absence of thiourea, or toward starting material recovery when excess thiourea is used. Both bromination and chlorination were highly efficient for primary, secondary, tertiary, and benzyl alcohols and tolerate a broad range of functional groups. Detailed electron paramagnetic resonance (EPR) studies, isotopic labeling, and other control experiments suggest a radical-based mechanism. The fact that the reaction is carried out at ambient conditions, uses ubiquitous and inexpensive reagents, boasts a wide scope, and can be made highly atom economic, makes this new methodology a very appealing option for this archetypical organic reaction.
Photocatalyic Appel reaction enabled by copper-based complexes in continuous flow
Minozzi, Clémentine,Grenier-Petel, Jean-Christophe,Parisien-Collette, Shawn,Collins, Shawn K.
supporting information, p. 2730 - 2736 (2018/11/21)
A copper-based photocatalyst, Cu(tmp)(BINAP)BF4, was found to be active in a photoredox Appel-type conversion of alcohols to bromides. The catalyst was identified from a screening of 50 complexes and promoted the transformation of primary and secondary alcohols to their corresponding bromides and carboxylic acids to their anhydrides. The protocol was also amendable and optimized under continuous flow conditions.
Single step transformation of PMB ethers to bromides using a CBr4-TPP reagent system
Yadav,Mishra, Rajesh Kumar
, p. 5419 - 5422 (2007/10/03)
PMB ethers are efficiently transformed to their corresponding bromides by a CBr4-TPP reagent system with a wide range of other functional groups also present in the substrate.
One-step conversion of protected alcohols into alkyl halides using dimethylphosgeniminium salt
Schlama,Gouverneur,Mioskowski
, p. 3517 - 3520 (2007/10/03)
Efficient conversion of tetrahydro-2-pyranyl (THP)protected alcohols into the corresponding halides using dichlorophosgeniminium chloride in the presence of tetraalkylammonium halide.
1,4-benzoquinone derivatives and benzene derivatives, and process for preparing the same
-
, (2008/06/13)
1,4-Benzoquinone derivatives and benzene derivatives having cerebral- and cardiac-blood flow improving activities and preventive activities of cerebral ischema with low toxicities, and thus are useful as activators for cardiac and cebral metabolisms, curing agents for heart failure, cardiac and cerebral blood flow improving agents, as well as anti-allergic agents for slow reacting allergy (IV-type allergy).
Electron Spin Resonance Spectra and Structure of the Radical Cations of Dibromoalkanes and Monobromoalkanes
Hasegawa, Akinori,Symons, Martyn C. R.,Shiotani, Masaru
, p. 657 - 666 (2007/10/02)
The radical cations of dibromoalkanes containing two bromines separated by an alkyl chain, have been generated by exposing dilute solutions of the dibromoalkanes in freon to X-rays at 77 K.Two types of e.s.r. spectra were observed for these cations.The spectra obtained for Br(CH2)nBr, n = 1-7, show septet features characteristic of two equivalent Br nuclei.The coupling constant of the septet increases and reaches a plateau, with increased n in these dibromoalkanes.This indicates that a positive hole in these cations is shared, not by the two Br nuclei connected through ?-delocalization over the chain, but by the two Br nuclei directly bonded to each other, in accordance with conclusions recently drawn from e.s.r. studies of dichloroalkane cations.In contrast, the e.s.r. spectra obtained for Br(CH2)nBr, n > 7, are more complicated.When similar experiments were carried out with H(CH2)nBr, n > 7, analogous spectra were obtained, indicating that the spectra observed for these dibromoalkanes can be interpreted in terms of hyperfine interactions to only one of the two Br nuclei and to two nuclei with nuclear spins of 1/2.This result, considered together with the fact that similar cationic centres were detected for H(CH2)nBr, n > 3, and with the spectral change observed for Br(CH2)nBr and H(CH2)nBr cations in different matrices (CCl2FCClF2, CCl3F, and CCl4) indicates that cyclization also occurs for these cations, the positive hole being occupied in a three-centre bond comprising a Br nucleus, a C nucleus (four atoms away from the Br nucleus), and an H nucleus bonded to the C nucleus.
Synthesis and Spectra of Two Novel Catenanes
Logemann, Enno,Rissler, Klaus,Schill, Gottfried,Fritz, Hans
, p. 2245 - 2260 (2007/10/02)
In multi-step reaction sequences the precatenanes 23b, c are synthesised.After breaking the chemical bonds between the aromatic nuclei and the bridge head atoms of the double bridged system the -catenanes 25 b, c are obtained.The 13C NMR and mass spectra of the precatenanes and catenanes are discussed.
