Face off: The rutheniumcomplexes of a new axially chiral PNN ligand (L) are highly efficient in the presence of dimethylsulfoxide (DMSO) for hydrogenation of both functionalized and unfunctionalized tert‐alkyl ketones. DMSO is thought to narrow down the many possible complex stereoisomers into a single facial L/Ru complex, thus enhancing the reactivity, selectivity, and productivity.
Silylative Kinetic Resolution of Racemic 2,2‐Dialkyl 5‐ and 6‐Membered Cyclic Benzylic Alcohol Derivatives Catalyzed by Chiral Guanidine, (
<i>R</i>
)‐
<i>N</i>
‐Methylbenzoguanidine
作者:Shuhei Yoshimatsu、Kenya Nakata
DOI:10.1002/adsc.201900761
日期:2019.10.22
Efficient silylative kineticresolution of racemic 2,2‐dialkyl 5‐ and 6‐membered cyclic benzylic alcohols was achieved using diphenylmethylchlorosilane (Ph2MeSiCl) or phenyldimethylchlorosilane (PhMe2SiCl) as a silyl source catalyzed by chiral guanidine. The reaction could be applied to a broad range of 2,2‐dialkyl 1‐indanols with good s‐values, irrespective of the electronic nature of the substituent
The antiinflammatory activity of synthetic cannabinoid nabilone in the rat model of carrageenan‐induced acute hindpaw inflammation was compared with that of the endocannabinoid palmitoylethanolamide and the nonsteroidal antiinflammatory drug indomethacin.Preliminary experiments in rats used a tetrad of behavioural tests, specific for tetrahydrocannabinol‐type activity in the CNS. These showed that the oral dose of nabilone 2.5 mg kg−1 had no cannabinoid psychoactivity.Intraplantar injection of carrageenan (1% w v−1) elicited a time‐dependent increase in paw volume and thermal hyperalgesia.Nabilone (0.75, 1.5, 2.5 mg kg−1, p.o.), given 1 h before carrageenan, reduced the development of oedema and the associated hyperalgesia in a dose‐related manner. Nabilone 2.5 mg kg−1, palmitoylethanolamide 10 mg kg−1 and indomethacin 5 mg kg−1, given p.o. 1 h before carrageenan, also reduced the inflammatory parameters in a time‐dependent manner.The selective CB2 cannabinoid receptor antagonist N‐[(1S)‐endo‐1,3,3‐trimethyl bicyclo [2.2.1]heptan‐2‐yl]‐5‐(4‐chloro‐3‐methylphenyl)‐1‐(4‐methylbenzyl)pyrazole‐3 carboxamide} (SR 144528), 3 mg kg−1 p.o. 1 h before nabilone and palmitoylethanolamide, prevented the anti‐oedema and antihyperalgesic effects of the two cannabinoid agonists 3 h after carrageenan.Our findings show the antiinflammatory effect of nabilone and confirm that of palmitoylethanolamide indicating that these actions are mediated by an uncharacterized CB2‐like cannabinoid receptor.British Journal of Pharmacology (2002) 135, 181–187; doi:10.1038/sj.bjp.0704466
An Unexpected Directing Effect in the Asymmetric Transfer Hydrogenation of α,α-Disubstituted Ketones
作者:Rina Soni、John-Michael Collinson、Guy C. Clarkson、Martin Wills
DOI:10.1021/ol201643v
日期:2011.8.19
alpha,alpha-Disubstituted ketones containing an aromatic ring or alkene are reduced in high enantiomeric excess using an asymmetric transfer hydrogenation catalyst. The sense of reduction indicates that the unsaturated region of the ketone adopts a position adjacent to the Ru-bound eta(6)-arene ring in the reduction transition state.