Aim: To investigate if the serum CC motif ligand 4 (CCL4) levels are linked to disease severity in patients with postmenopausal osteoporosis (PMOP). Patients & methods: We enrolled 66 PMOP females, 68 postmenopausal nonosteoporotic women and 67 healthy women of childbearing age. Bone mineral densities were assessed with dual x-ray absorptiometry scans. The Oswestry disability index and the visual analog scale were employed to quantify functional ability and severity of symptoms. Serum CCL4 levels were examined with a quantitative sandwich enzyme-linked immunosorbent assay. Results: We observed a significant negative correlation of CCL4 serum levels with bone mineral density. Furthermore, serum CCL4 concentrations were significantly related to the visual analog scale and Oswestry Disability Index scores. Conclusion: Serum CCL4 is a potential biomarker to evaluate disease severity in PMOP females.
Chiral amines are widely used as chiral ligands, auxiliaries, resolving agents, and important intermediates in synthetic chemistry. Asymmetric hydrogenation of enamines such as enamides is an atom economic and straightforward protocol for the preparation of chiral amines. In 1972, Kagan reported the first example of asymmetric hydrogenation of enamides with chiral Rh-DIOP complex as a catalyst [1]. This opened a new window for the asymmetric synthesis of chiral N-acyl amines although the enantioselectivity of the reaction was not more than 78% ee (Scheme 8.1). When Noyori et al. introduced chiral Ru-BINAP, it significantly increased the level of enantioselectivity to 99.5% ee in the asymmetric hydrogenation of N-acyl-1-alkylidenetetrahydroisoquinolines [2]. However, this ruthenium-catalyzed asymmetric hydrogenation is very sensitive to the stereochemistry of the enamide, with only the (Z)-isomer of the enamide being hydrogenated while the (E)-isomer was recovered intact (Scheme 8.2). Another breakthrough in this field came in 1996 when Burk et al. showed that chiral rhodium complexes bearing a diphosphine ligand Me-DuPHOS or Me-BPE could hydrogenate a-arylenamides to yield a wide variety of valuable a-1-arylethylamine derivatives with high enantioselectivities (up to 98.5% ee) (Scheme 8.3) [3]. The merit of this hydrogenation is that both (E)-and (Z)-isomers of b-substituted enamides can be hydrogenated, thus enlarging the substrate scope of the reaction. Subsequently, many efficient diphosphines, such as BICP (bis(diphenylphosphino)dicyclopentane) [4], PennPhosP, NHAc NHAc 1 bar H 2 [RhCl(COD) 2 ] 2 /(S,S)-DIOP EtOH-C 6 H 6 (2 :1), rt 95% yield, 78% ee PPh 2 PPh 2 O O (S,S)-DIOP Scheme 8.1 Rh-DIOP catalyzed asymmetric hydrogenation of enamides.
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