N-(6,7-Dichloro-2,3-dioxo-1,2,3,4-tetrahydroquinoxalin-5-yl)-N-alkylsulfonamides as peripherally restricted N-methyl-d-aspartate receptor antagonists for the treatment of pain

Cobalt-catalyzed enantioselective C-H/N-H annulation of aryl sulfonamides with allenes or alkynes: facile access to C-N axially chiral sultams

Herein we report a cobalt-catalyzed enantioselective C-H/N-H annulation of aryl sulfonamides with allenes and alkynes, using either chemical or electrochemical oxidation. By using O2 as the oxidant, the annulation with allenes proceeds efficiently with a low catalyst/ligand loading of 5 mol% and tolerates a wide range of allenes, including 2,3-butadienoate, allenylphosphonate, and phenylallene, resulting in C-N axially chiral sultams with high enantio-, regio-, and position selectivities. The annulation with alkynes also exhibits excellent enantiocontrol (up to >99% ee) with a variety of functional aryl sulfonamides, and internal and terminal alkynes. Furthermore, electrochemical oxidative C-H/N-H annulation with alkynes is achieved in a simple undivided cell, demonstrating the versatility and robustness of the cobalt/Salox system. The gram-scale synthesis and asymmetric catalysis further highlight the practical utility of this method.

Catalytic Enantioselective Synthesis of N-C Axially Chiral N-(2,6-Disubstituted-phenyl)sulfonamides through Chiral Pd-Catalyzed N-Allylation

Recently, catalytic enantioselective syntheses of N-C axially chiral compounds have been reported by many groups. Most N-C axially chiral compounds prepared through a catalytic asymmetric reaction possess carboxamide or nitrogen-containing aromatic heterocycle skeletons. On the other hand, although N-C axially chiral sulfonamide derivatives are known, their catalytic enantioselective synthesis is relatively underexplored. We found that the reaction (Tsuji-Trost allylation) of allyl acetate with secondary sulfonamides bearing a 2-arylethynyl-6-methylphenyl group on the nitrogen atom proceeds with good enantioselectivity (up to 92% ee) in the presence of (S,S)-Trost ligand-(allyl-PdCl)₂ catalyst, affording rotationally stable N-C axially chiral N-allylated sulfonamides. Furthermore, the absolute stereochemistry of the major enantiomer was determined by X-ray single crystal structural analysis and the origin of the enantioselectivity was considered.

Organocatalytic atroposelective N-alkylation: divergent synthesis of axially chiral sulfonamides and biaryl amino phenols

Axial chirality exists ubiquitously in numerous natural products and has been extensively recognized for decades in pharmaceuticals and enantioselective transformations. The development of efficient methodologies to obtain enantiopure structures bearing...

Stable C-N axial chirality in 1-aryluracil scaffold and differences in in vitro metabolic clearance between atropisomers of PDE4 inhibitor

We report herein the stable C-N axial chirality in a 1-phenyl-6-aminouracil scaffold owing to the presence of various functional groups at the ortho-position of the N(1)-phenyl group. Racemic 1-phenyl-6-aminouracils were first separated by chiral HPLC or converting them to the corresponding diastereomers using a chiral resolving agent. We then determined the rotational barrier of each atropisomer by a thermal racemization method and found that these compounds have rotational barriers similar to other C-N axially chiral biaryls. In addition, there was a good correlation between the rotational barriers and van der Waals radii of an ortho-substituent of the N(1)-phenyl group. To explore the possibility of the chiral 1-phenyl-6-aminouracil scaffold as a drug lead, we synthesized both atropisomers as phosphodiesterase-4 inhibitors 10. The atropisomers showed significantly different metabolic stabilities while their PDE4 inhibitory activities were somewhat similar. This finding demonstrates the potential utility of stable C-N bond atropisomers in the development of chiral drugs.

Design, synthesis and pharmacological evaluation of (E)-3,4-dihydroxy styryl sulfonamides derivatives as multifunctional neuroprotective agents against oxidative and inflammatory injury

A novel class of (E)-3,4-dihydroxy styryl sulfonamides and their 3,4-diacetylated derivatives as caffeic acid phenethyl ester (CAPE) analogs was designed and prepared for improving stability and solubility of the lead compound. Their neuroprotective properties were assessed by several models. The results showed that target compounds displayed positive free radical quenching abilities, superior to that of CAPE. Compounds 6j-k and 7j-k demonstrated remarkable protection effects against damage induced by hydrogen peroxide which were apparently stronger than that of CAPE. Most of target compounds could inhibit nitric oxide production. Additionally, target compounds showed high blood-brain barrier permeability.