Exploring Interrupted Nazarov Cyclizations Using Tethered Sulfonamide Nucleophiles: Insights into Capture Pathways.

This manuscript describes a study of diverse reaction outcomes that stem from the ionization of -alkynyl-Prins adducts. Experimental results have demonstrated unexpected behavior in the nitrogen-containing systems compared to the analogous oxygen derivatives derived from -Prins/-Nazarov sequences. In-depth experimental studies and computational analysis revealed an intricate mechanism involving competing -Nazarov and -Nazarov pathways.

Hydroxychloroquine and a low antiresorptive activity bisphosphonate conjugate prevent and reverse ovariectomy-induced bone loss in mice through dual antiresorptive and anabolic effects.

Osteoporosis remains incurable. The most widely used antiresorptive agents, bisphosphonates (BPs), also inhibit bone formation, while the anabolic agent, teriparatide, does not inhibit bone resorption, and thus they have limited efficacy in preventing osteoporotic fractures and cause some side effects. Thus, there is an unmet need to develop dual antiresorptive and anabolic agents to prevent and treat osteoporosis.

Hydroxychloroquine and a low activity bisphosphonate conjugate prevent and reverse ovariectomy-induced bone loss in mice through dual antiresorptive and anabolic effects.

Osteoporosis is incurable because there are no dual antiresorptive and anabolic therapeutic agents that can be administered long-term. The most widely used antiresorptive agents, bisphosphonates (BPs), also inhibit bone formation and thus have limited effect in preventing osteoporotic fracture. Hydroxychloroquine (HCQ), which is used to treat rheumatoid arthritis, prevents the lysosomal degradation of TNF receptor-associated factor 3 (TRAF3), an NF-κB adaptor protein that limits bone resorption and maintains bone formation.

Nitrogen-interrupted -Prins/-Nazarov fragment coupling cascade for the synthesis of indolines.

The nitrogen-interrupted Nazarov cyclization can be a powerful method for the stereocontrolled synthesis of sp-rich -heterocycles. However, due to the incompatibility between the basicity of nitrogen and the acidic reaction conditions, examples of this type of Nazarov cyclization are scarce. Herein, we report a one-pot nitrogen-interrupted -Prins/-Nazarov coupling cascade that joins two simple building blocks, an enyne and a carbonyl partner, to furnish functionalized cyclopenta[]indolines with up to four contiguous stereocenters.

Divergent Reactivity of Triaryldivinyl Ketones: Competing 4π and Putative 6π Electrocyclization Pathways.

This work describes an acid-promoted cyclization of triaryldivinyl ketones containing a thiophene moiety in the α-position. Two cyclization pathways are accessible: one a 4π-Nazarov cyclization and the other we propose to proceed through a 6π electrocyclic mechanism. The relative proportion of products from these divergent pathways is affected by reaction conditions and steric bulk in the substrate.