17419-81-7Relevant articles and documents
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Levin,Pendergrass
, p. 2436 (1947)
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A Practical and Stereoselective In Situ NHC-Cobalt Catalytic System for Hydrogenation of Ketones and Aldehydes
Zhong, Rui,Wei, Zeyuan,Zhang, Wei,Liu, Shun,Liu, Qiang
, p. 1552 - 1566 (2019/06/14)
Homogeneous catalytic hydrogenation of carbonyl groups is a synthetically useful and widely applied organic transformation. Sustainable chemistry goals require replacing conventional noble transition metal catalysts for hydrogenation by earth-abundant base metals. Herein, we report how a practical in situ catalytic system generated by easily available pincer NHC precursors, CoCl2, and a base enabled efficient and high-yielding hydrogenation of a broad range of ketones and aldehydes (over 50 examples and a maximum turnover number [TON] of 2,610). This is the first example of NHC-Co-catalyzed hydrogenation of C=O bonds using flexible pincer NHC ligands consisting of a N-H substructure. Diastereodivergent hydrogenation of substituted cyclohexanone derivatives was also realized by fine-tuning of the steric bulk of pincer NHC ligands. Additionally, a bis(NHCs)-Co complex was successfully isolated and fully characterized, and it exhibits excellent catalytic activity that equals that of the in-situ-formed catalytic system. Catalytic hydrogenation is a powerful tool for the reduction of organic compounds in both fine and bulk chemical industries. To improve sustainability, more ecofriendly, inexpensive, and earth-abundant base metals should be employed to replace the precious metals that currently dominate the development of hydrogenation catalysts. However, the majority of the base-metal catalysts that have been reported involve expensive, complex, and often air- and moisture-sensitive phosphine ligands, impeding their widespread application. From a mixture of the stable CoCl2, imidazole salts, and a base, our newly developed catalytic system that formed easily in situ enables efficient and stereoselective hydrogenation of C=O bonds. We anticipate that this easily accessible catalytic system will create opportunities for the design of practical base-metal hydrogenation catalysts. A practical in situ catalytic system generated by a mixture of easily available pincer NHC precursors, CoCl2, and a base enabled highly efficient hydrogenation of a broad range of ketones and aldehydes (over 50 examples and up to a turnover number [TON] of 2,610). Diastereodivergent hydrogenation of substituted cyclohexanone derivatives was also realized in high selectivities. Moreover, the preparation of a well-defined bis(NHCs)-Co complex via this pincer NHC ligand consisting of a N-H substructure was successful, and it exhibits equally excellent catalytic activity for the hydrogenation of C=O bonds.
DOPAMINE D3 RECEPTOR ANTAGONISTS HAVING A BICYCLO MOIETY
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Paragraph 1087; 1088, (2017/02/28)
The disclosure provides compounds having formula (I), wherein the substituents are as defined herein. The compounds are useful for modulating the dopamine D3 receptor and for treating conditions associated therewith, such as addictions, drug dependency, and psychiatric conditions.
Tetraoxanes as inhibitors of apicomplexan parasites Plasmodium falciparum and Toxoplasma gondii growth and anti-cancer molecules
Opsenica, Dejan M.,Radivojevic, Jelena,Matic, Ivana Z.,?tajner, Tijana,Kne?evic-U?aj, Slavica,Djurkovic-Djakovic, Olgica,?olaja, Bogdan A.
, p. 1339 - 1359 (2016/02/18)
New cyclohexylidene 1,2,4,5-tetraoxanes with polar guanidine and urea based groups were synthesized and evaluated for their antimalarial activity against chloroquine resistant and susceptible Plasmodium falciparum strains. The derivatives showed moderate, nM range antimalarial activities and low cytotoxicity. The N-phenylurea derivative 24 exhibited the best resistance indices (RIW2 = 0.44, RITM91C235 = 0.80) and was not toxic against human normal peripheral blood mononuclear cells (IC50 > 200 μM). Seven derivatives were tested in vitro against four human cancer cell lines and they demonstrated high selectivity toward leukaemia K562 cells. One compound, derivative 21 with a primary amino group, was the first tetraoxane tested in vivo against Toxoplasma gondii as another apicomplexan parasite. Subcutaneous administration at a dose of 10 mg kg-1 day-1 for 8 days allowed the survival of 20 % of infected mice, thus demonstrating the high potential of tetraoxanes for the treatment of apicomplexan parasites.
