Bone diseases may not be imminently life-threatening or a leading cause of death such as heart diseases or cancers. However, as aging population grows in almost every part of the world, they surely impose significant socioeconomic burden on the society, not to mention the patients and their families. Osteoporosis is the most common type of bone disease, which frequently develops in seniors, especially in postmenopausal women. Although currently several anti-osteoclastic drugs designed to suppress excessive osteoclast activation, a major cause of osteoporosis, are commercially available, accompanying adverse effects ranging from mild to severe have been reported as well. Natural products have become increasingly popular because of their effectiveness with fewer side effects. Isoliquiritigenin (ILG), a natural flavonoid from licorice, has been reported to suppress osteoclast differentiation and activation. In the present study, newly synthesized ILG derivatives were screened for their anti-osteoporotic activity as more potent substitute candidates to ILG. Out of the 12 ILG derivatives tested, two compounds demonstrated significantly improved bone loss in vitro by inhibiting both osteoclastogenesis and osteoclast activity. The results of the present study indicate that these compounds may serve as a potential drug for osteoporosis and warrant further studies to evaluate their in vivo efficacy.

An efficient and highly chemo- and stereoselective copper-catalyzed hydroamination of oxa- and azabenzo­norbornadienes with various pyrazole derivatives is described. This catalytic process is promoted by the presence of N-heterocyclic carbene ligands and KOt-Bu under mild and simple reaction conditions, and allows for the direct synthesis of new and versatile functionalized oxa­(aza)­benzo­norbornyl pyrazoles starting from readily available oxa­(aza)­bicyclic alkenes. The synthetic utility of this method was demonstrated by the transformation of the obtained products into pyrazolyl-substituted naphthalenes.

A highly chemo‐ and regioselective KOt‐Bu‐catalyzed addition of substituted indoles to terminal or disubstituted allylic sulfones at the indole N‐position is reported. The catalytic protocol allows for the efficient and mild synthesis of a broad range of new and versatile sulfonyl‐substituted indoles and azoles bearing various functional groups from readily available starting materials in good to excellent yields with complete regioselectivity.

The highly regioselective copper‐catalyzed hydroaminations of terminal or γ‐substituted allylic sulfones with aromatic amines is described. The combination of an N‐heterocyclic carbene‐copper complex and KOt‐Bu plays an important role in promoting selective amination under mild reaction conditions. This catalytic reaction tolerates a wide range of functional groups and enables the efficient syntheses of new and versatile functionalized β‐amino sulfones in high yields (up to 98%) with >98% regioselectivity.