42925-15-5Relevant academic research and scientific papers
Hydroalkylation of Unactivated Olefins via Visible-Light-Driven Dual Hydrogen Atom Transfer Catalysis
Chang, Rui,Funes-Ardoiz, Ignacio,Lei, Guangyue,Xu, Meichen,Ye, Juntao
supporting information, p. 11251 - 11261 (2021/08/03)
Radical hydroalkylation of olefins enabled by hydrogen atom transfer (HAT) catalysis represents a straightforward means to access C(sp3)-rich molecules from abundant feedstock chemicals without the need for prefunctionalization. While Giese-type hydroalkylation of activated olefins initiated by HAT of hydridic carbon-hydrogen bonds is well-precedented, hydroalkylation of unactivated olefins in a similar fashion remains elusive, primarily owing to a lack of general methods to overcome the inherent polarity-mismatch in this scenario. Here, we report the use of visible-light-driven dual HAT catalysis to achieve this goal, where catalytic amounts of an amine-borane and an in situ generated thiol were utilized as the hydrogen atom abstractor and donor, respectively. The reaction is completely atom-economical and exhibits a broad scope. Experimental and computational studies support the proposed mechanism and suggest that hydrogen-bonding between the amine-borane and substrates is beneficial to improving the reaction efficiency.
Synthesis and activity of a novel series of 3-biarylquinuclidine squalene synthase inhibitors
Brown, George R.,Clarke, David S.,Foubister, Alan J.,Freeman, Susan,Harrison, Peter J.,Johnson, Michael C.,Mallion, Keith B.,McCormick, John,McTaggart, Fergus,Reid, Alan C.,Smith, Graham J.,Taylor, Melvyn J.
, p. 2971 - 2979 (2007/10/03)
Quinuclidines with a 3-biaryl substituent are a new class of potent, orally active squalene synthase (SQS) inhibitors. Variants around these rigid structures indicate key structural requirements for cationic SQS inhibitors. Thus the lower in vitro potency found for quinuclidines bearing 3- substituents, which did not overlay the biphenyl group of 3-(biphenyl-4-yl)- 3-hydroxyquinuclidine (2) (IC50 = 16 nM, rat microsomal SQS), implied a directional requirement for the 3-substituent. Similarly, the lower potency of the 3-terphenyl analogue 6 (IC50 = 370 nM) indicated size constraints for this substituent. In compounds with a linking group between the quinuclidine and biphenyl ring, linking groups of lower lipophilicity were less well tolerated (e.g., 17, CH2CH2, IC50 = 5 nM vs 19, NHCO, IC50 = 1.2 μM). Replacement of the distal phenyl ring of 2 with a more polar pyridine heterocycle caused a reduction in in vitro potency. In general, good in vivo activity in the rat was restricted to 3-hydroxy analogues, with the 3-[4-(pyrid-4-yl)phenyl] derivative 39 (IC50 = 161 nM) showing the best inhibition (following oral dosing) of cholesterol biosynthesis from mevalonate (ED50 = 2.7 mg/kg).
