Two chiral carboxylic acid functionalized micro- and mesoporous metal-organic frameworks (MOFs) are constructed by the stepwise assembly of triple-stranded heptametallic helicates with six carboxylic acid groups. The mesoporous MOF with permanent porosity functions as a host for encapsulation of an enantiopure organic amine catalyst by combining carboxylic acids and chiral amines in situ through acid-base interactions. The organocatalyst-loaded framework is shown to be an efficient and recyclable heterogeneous catalyst for the asymmetric direct aldol reactions with significantly enhanced stereoselectivity in relative to the homogeneous organocatalyst.

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A dynamic porous coordination network with a hydrophobic channel was assembled from stretchable 1D metallosalen polymer, which has the ability to recognize and, particularly, separate aromatic hydrocarbons from aliphatic mixtures with high selectivity.

Osteoporosis, an osteolytic disease that affects millions of people worldwide, features a bone remodeling imbalance between bone resorption by osteoclasts and bone formation by osteoblasts. Identifying dual target-directed agents that inhibit excessive bone resorption and increase bone formation is considered an efficient strategy for developing new osteoporosis treatments. Rhein, a natural anthraquinone, can be isolated from various Asian herbal medicines. Rhein and its derivatives have been reported to have various beneficial pharmacological effects, especially their bone-targeting ability and anti-osteoclastogenesis activity. Moreover, hydrogen sulfide (H 2 S) was reported to prevent ovariectomy-(OVX-) induced bone loss by enhancing bone formation, and sulfur replacement therapy has been considered a novel and plausible therapeutic option. Based on this information, we synthesized a rheinderived thioamide (RT) and investigated its effects on bone resorption and bone formation in vitro and in vivo. It has been found that the RT-inhibited receptor activator of the nuclear factor-kB (NF-kB) ligand-(RANKL-) induced osteoclastogenesis and bone resorption in a dose-dependent manner. The expression of osteoclast marker genes was also suppressed by RT treatment. Furthermore, exploration of signal transduction pathways indicated that RT markedly blocked RANKL-induced osteoclastogenesis by attenuating MAPK pathways. However, RT treatment in an osteoblastic cell line, MC3TE-E1, indicated that RT led to an increase in the deposition of minerals and the expression of osteoblast marker genes, as demonstrated by Alizarin Red staining and alkaline phosphatase activity. Importantly, an OVX mouse model showed that RT could attenuate the bone loss in estrogen deficiency-induced osteoporosis in vivo with a smart H 2 S-releasing property and that there was a considerable improvement in the biomechanical properties of bone. Accordingly, our current work highlights the dual regulation of bone remodeling by the rhein-derived molecule RT. This may be a highly promising approach for a new type of anti-osteoporosis agent.Journal of Bone and Mineral Research 50 ng/mL RANKL for 3 days. Cell lysates were then subjected to Western blotting analysis for cathepsin K. (H) The ratio of the density of cathepsin K. bands relative to b-actin bands was then determined using Image J. n ¼ 3. Ã p < 0.5 and ÃÃ p < 0.01 versus control. 366 JIANG ET AL. Journal of Bone and Mineral ResearchFig 3. Rhein-derived thioamide (RT) suppresses the mRNA expressions of osteoclast marker genes and phosphorylations of p38 and ERK cascade. (A-D)Bone marrow monocytes/macrophages (BMMs) were stimulated with M-CSF and RANKL in the presence of different doses of RT for 3 days. Osteoclasts marker gene levels of NFATc1, c-fos, TRAP, V-ATPase2 were determined by quantitative RT-PCR analysis of RT at indicated concentrations in combination with M-CSF and RANKL in BMMs. The results were normalized to b-actin expression and expressed as fold change relative to gene expression i...

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