619-22-7Relevant articles and documents
Selective Benzylic CH-Borylations by Tandem Cobalt Catalysis
Bauer, Matthias,Ghosh, Pradip,Jacobi von Wangelin, Axel,Schoch, Roland
supporting information, (2021/11/27)
Metal-catalyzed C?H activations are environmentally and economically attractive synthetic strategies for the construction of functional molecules as they obviate the need for pre-functionalized substrates and minimize waste generation. Great challenges reside in the control of selectivities, the utilization of unbiased hydrocarbons, and the operation of atom-economical dehydrocoupling mechanisms. An especially mild borylation of benzylic CH bonds was developed with the ligand-free pre-catalyst Co[N(SiMe3)2]2 and the bench-stable and inexpensive borylation reagent B2pin2 that produces H2 as the only by-product. A full set of kinetic, spectroscopic, and preparative mechanistic studies are indicative of a tandem catalysis mechanism of CH-borylation and dehydrocoupling via molecular CoI catalysts.
Reduction of N,N-Dimethylcarboxamides to Aldehydes by Sodium Hydride–Iodide Composite
Chan, Guo Hao,Ong, Derek Yiren,Yen, Zhihao,Chiba, Shunsuke
, (2018/05/14)
A new and concise protocol for selective reduction of N,N-dimethylamides into aldehydes was established using sodium hydride (NaH) in the presence of sodium iodide (NaI) under mild reaction conditions. The present protocol with the NaH-NaI composite allows for reduction of not only aromatic and heteroaromatic but also aliphatic N,N-dimethylamides with wide substituent compatibility. Retention of α-chirality in the reduction of α-enantioriched amides was accomplished. Use of sodium deuteride (NaD) offers a new step-economical alternative to prepare deuterated aldehydes with high deuterium incorporation rate. The NaH-NaI composite exhibits unique chemoselectivity for reduction of N,N-dimethylamides over ketones.
Tau-Centric Multitarget Approach for Alzheimer's Disease: Development of First-in-Class Dual Glycogen Synthase Kinase 3β and Tau-Aggregation Inhibitors
Gandini, Annachiara,Bartolini, Manuela,Tedesco, Daniele,Martinez-Gonzalez, Loreto,Roca, Carlos,Campillo, Nuria E.,Zaldivar-Diez, Josefa,Perez, Concepción,Zuccheri, Giampaolo,Miti, Andrea,Feoli, Alessandra,Castellano, Sabrina,Petralla, Sabrina,Monti, Barbara,Rossi, Martina,Moda, Fabio,Legname, Giuseppe,Martinez, Ana,Bolognesi, Maria Laura
supporting information, p. 7640 - 7656 (2018/09/06)
Several findings propose the altered tau protein network as an important target for Alzheimer's disease (AD). Particularly, two points of pharmacological intervention can be envisaged: inhibition of phosphorylating tau kinase GSK-3β and tau aggregation process. On the basis of this consideration and on our interest in multitarget paradigms in AD, we report on the discovery of 2,4-thiazolidinedione derivatives endowed with such a profile. 28 and 30 displayed micromolar IC50 values toward GSK-3β, together with the capacity of inhibiting AcPHF6 aggregation of 60% and 80% at 10 μM, respectively. In addition, they showed PAMPA-BBB permeability, together with a suitable cellular safety profile. 30 also displayed inhibition of both K18 and full-length tau aggregations. Finally, both compounds were able to improve cell viability in an okadaic acid-induced neurodegeneration cell model. To the best of our knowledge, 28 and 30 are the first balanced, nontoxic, dual-acting compounds hitting tau cascade at two different hubs.
Laying the way to meta-functionalization of naphthalene proton sponge via the use of Schlosser's superbase
Antonov, Alexander S.,Bardakov, Victor G.,Pozharskii, Alexander F.,Vovk, Mikhail A.,Misharev, Alexander D.
, p. 18 - 25 (2017/12/26)
Lithiation of 1,8-bis(dimethylamino)naphthalene (DMAN) with Schlosser's superbase (n-BuLi–t-BuOK) in the presence of TMEDA in hexane was examined. It has been shown that, compared with previously studied n-BuLi–TMEDA or t-BuLi–TMEDA mixtures, this reagent provides much more selective meta-lithiation. A variety of 3-substituted and 3,6-disubstituted derivatives of DMAN has been prepared in a good to reasonable yield after quenching the reaction mass with different electrophiles. A possibility of further functionalization of thus introduced meta-substituents to synthesize more complex 3-substituted derivatives of DMAN is also demonstrated.
Copper-Catalyzed Aerobic Oxidative Amidation of Benzyl Alcohols
Krabbe, Scott W.,Chan, Vincent S.,Franczyk, Thaddeus S.,Shekhar, Shashank,Napolitano, José G.,Presto, Carmina A.,Simanis, Justin A.
, p. 10688 - 10697 (2016/11/29)
A Cu-catalyzed synthesis of amides from alcohols and secondary amines using the oxygen in air as the terminal oxidant has been developed. The methodology is operationally simple requiring no high pressure equipment or handling of pure oxygen. The commercially available, nonprecious metal catalyst, Cu(phen)Cl2, in conjunction with di-tert-butyl hydrazine dicarboxylate and an inorganic base provides a variety of benzamides in moderate to excellent yields. The pKa of amine conjugate acid and electronics of alcohol were shown to impact the selection of base for optimal reactivity. A mechanism consistent with the observed reactivity trends, KIE, and Hammett study is proposed.
Cobalt-Catalyzed Benzylic Borylation: Enabling Polyborylation and Functionalization of Remote, Unactivated C(sp3)-H Bonds
Palmer, W. Neil,Obligacion, Jennifer V.,Pappas, Iraklis,Chirik, Paul J.
supporting information, p. 766 - 769 (2016/02/05)
Cobalt dialkyl and bis(carboxylate) complexes bearing α-diimine ligands have been synthesized and demonstrated as active for the C(sp3)-H borylation of a range of substituted alkyl arenes using B2Pin2 (Pin = pinacolate) as the boron source. At longer reaction times, rare examples of polyborylation were observed, and in the case of toluene, all three benzylic C-H positions were functionalized. Coupling benzylic C-H activation with alkyl isomerization enabled a base-metal-catalyzed method for the borylation of remote, unactivated C(sp3)-H bonds.
Structurally Simple Benzylidene-Type Photolabile Diol Protecting Groups
Ding, Xiong,Devalankar, Dattatray A.,Wang, Pengfei
supporting information, p. 5396 - 5399 (2016/11/06)
Two structurally simple photolabile protecting groups for releasing 1,2- and 1,3-diols have been developed. The diols can be protected in high yields and released from their corresponding acetals with high chemical efficiency.
A practical in situ generation of the schwartz reagent. reduction of tertiary amides to aldehydes and hydrozirconation
Zhao, Yigang,Snieckus, Victor
supporting information, p. 390 - 393 (2014/04/03)
A new, highly efficient in situ protocol (Cp2ZrCl2/LiAlH(OBu-t)3) is described for the generation of the Schwartz reagent which provides a convenient method for the amide to aldehyde reduction and the regioselective hydrozirconation-iodination of alkynes and alkenes. Highlighted are chemoselective reductions of benzamides derived by directed ortho metalation (DoM) chemistry, allowing the synthesis of valuable 1,2,3-substituted benzaldehydes. The single-step, three-component process proceeds in a very short reaction time, shows excellent functional group compatibility, and uses inexpensive and long-storage stable reducing reagents.
Aggregation-induced emission of GFP-like chromophores via exclusion of solvent-solute hydrogen bonding
Tou, Sio-Lon,Huang, Guan-Jhih,Chen, Po-Cheng,Chang, Huan-Tsung,Tsai, Jun-Yun,Yang, Jye-Shane
, p. 620 - 622 (2014/01/06)
The fluorescence of GFP-like chromophores in aqueous solutions is turned on upon forming aggregates or embedment in cell membranes as a result of exclusion of solvent-solute H-bonding. The Royal Society of Chemistry 2014.
