Diarylcyclohexanones: synthons for new bicyclic compounds

Abstract  

We used 4-acetyl-3,5-diarylcyclohexanones bearing two different aromatic rings as synthons for the preparation of 6,7-diaryl-4-(dialkylamino)bicyclo[2.2.2]octanones, starting materials for new antiprotozoals.     

Unprecedented Selectivity via Electronic Substrate Recognition in the 1,4‐Addition to Cyclic Olefins Using a Chiral Disulfoxide Rhodium Catalyst

From zero to hero? Sulfoxides are generally not considered useful ligand entities in asymmetric metal catalysis. However, a chiral disulfoxide as a chelating ligand in the rhodium‐catalyzed 1,4‐addition of aryl boronic acids to cyclic, α,β‐unsaturated ketones and esters gives impressive catalytic results, thus opening the door to future applications of this new chiral ligand class.

     

Influence of finite spatial resolution on single- and double-pass femtosecond pulse shapers

We investigate the influence of the finite spatial resolution of a typical 4f pulse-shaping setup in a single- and double-pass configuration on the shaped waveforms. Specifically, we calculate and measure the space-frequency distribution at the focal plane of a lens following the shaping setup and show that steep amplitude or phase jumps, as they appear with pixelated spatial light modulators, are affected by a finite spatial resolution.     

Structural Requirements for the Antiprotozoal Activity of 4-Aminobicyclo[2.2.2]octan-2-ols

Several 4-aminobicyclo[2.2.2]octan-2-ones and -ols were synthesized using different pathways. The new compounds were investigated for their activity against Trypanosoma b. rhodesiense, the causative organism of East African sleeping sickness and Plasmodium falciparum the protozoan parasite which causes Malaria tropica. The results are compared to the activities of known compounds and the influence of the substitution of the bicyclo[2.2.2]octane skeleton on the biological activities is discussed.     

A Compactness Theorem for Complete Ricci Shrinkers

We prove precompactness in an orbifold Cheeger–Gromov sense of complete gradient Ricci shrinkers with a lower bound on their entropy and a local integral Riemann bound. We do not need any pointwise curvature assumptions, volume or diameter bounds. In dimension four, under a technical assumption, we can replace the local integral Riemann bound by an upper bound for the Euler characteristic. The proof relies on a Gauss–Bonnet with cutoff argument.     

SARs of the antiprotozoal action of 6,7-diaryl-bicyclo[2.2.2]octan-2-ols

Abstract  Several 4-amino-6,7-diarylbicyclo[2.2.2]octan-2-ols bearing varying substituents on the aromatic rings were synthesized following a manual method for applying the Hansch approach. All new compounds were tested for their activity against the causative organisms of East African sleeping sickness and malaria tropica. Structure activity relationships are discussed. Graphical abstract        

Atomic resolution analyses of the binding of xylobiose-derived deoxynojirimycin and isofagomine to xylanase Xyn10A

The atomic resolution structures of xylobiose-derived isofagomine and xylobiose-derived deoxynojirimycin in complex with the xylanase Xyn10A from Streptomyces lividans reveal undistorted (4)C(1) chair conformed sugars and, in the case of the deoxynojirimycin analogue, suggest unusual pK(a) changes of the enzyme's catalytic machinery upon binding.