Atomic Ruthenium-Promoted Cadmium Sulfide for Photocatalytic Production of Amino Acids from Biomass Derivatives.

Amino acids are the building blocks of proteins and are widely used as important ingredients for other nitrogen-containing molecules. Here, we report the sustainable production of amino acids from biomass-derived hydroxy acids with high activity under visible-light irradiation and mild conditions, using atomic ruthenium-promoted cadmium sulfide (Ru1/CdS). On a metal basis, the optimized Ru1/CdS exhibits a maximal alanine formation rate of 26.0 molAla ⋅ gRu -1 ⋅ h-1, which is 1.7 times and more than two orders of magnitude higher than that of its nanoparticle counterpart and the conventional thermocatalytic process, respectively. Integrated spectroscopic analysis and density functional theory calculations attribute the high performance of Ru1/CdS to the facilitated charge separation and O-H bond dissociation of the α-hydroxy group, here of lactic acid. The operando nuclear magnetic resonance further infers a unique "double activation" mechanism of both the CH-OH and CH3-CH-OH structures in lactic acid, which significantly accelerates its photocatalytic amination toward alanine.

Leveraging Chiral Zr(IV)-Based Metal-Organic Frameworks To Elucidate Catalytically Active Rh Species in Asymmetric Hydrogenation Reactions.

One of the most widely employed strategies to produce chiral molecules involves the asymmetric hydrogenation of functionalized olefins using rhodium catalysts. Despite their excellent performance, the exact identity of the active Rh species is still ambiguous as each site may plausibly feature one or two phosphorus ligands. In this work, we used a sequential postsynthetic modification approach to successfully incorporate single-site Rh species into a zirconium-based metal-organic framework comprised of chiral spinol-based ligands. These Rh species feature one phosphorus ligand per Rh, which contrasts with the molecular analogue that contains two phosphorus ligands per Rh site. Following extensive characterization of the Rh-monophosphorus material using techniques including solid-state NMR and extended X-ray absorption fine-structure (EXAFS) spectroscopy, we studied their catalytic performance in the asymmetric hydrogenations of enamides and α-dehydroamino acid esters and observed excellent yields and enantioselectivities (up to 99.9% ee). Notably, the Rh-monophosphorus catalyst is 5 times more active than the homogeneous Rh-biphosphorus control, which we attributed to the higher activity of the single-site Rh-monophosphorus species and the confined MOF cavities that can enrich reactants. In addition, we observed a unique topology-dependent behavior in which linker expansion leads to the formation of a novel Zr-MOF with a distinct 4,8-connected net that cannot be phosphorylated, presumably due to intense tensile strain and steric repulsion present within this framework. Finally, we demonstrate the utility of this single-site Rh-monophosphorus catalyst in the gram-scale synthesis of (R)-cinacalcet hydrochloride, a first-in-class drug in the therapy of secondary hyperparathyroidism and parathyroid carcinoma, with 99.1% ee.

[Study on the mechanism of autologous platelet-rich gel to treat the refractory diabetic dermal ulcers].

OBJECTIVE: To investigate the mechanism of autologous platelet-rich gel (APG)in the treatment of refractory diabetic dermal ulcers. METHODS: After the treatment of refractory diabetic dermal ulcers with APG at 0, 3, 6, 9, 15 days, the protein levels of PDGF-BB, VEGF, IGF-1, EGF and TGF-beta1 in the granulation tissue were detected by ELISA, while the dimensions of ulcer area were measured at the same time. RESULTS: The areas of ulcers were obviously reduced at the third and fifteen day after APG treatment (P < 0.05). The concentrations of these 5 growth factors in the granulation tissue were began to increase after 3 days treatment, the peak of PDGF-BB emerged at the third day (P < 0.05), and the peaks of VEGF, IGF-1, TGF-beta1 were found at the ninth day (P < 0.05). The concentration of VEGF increased 2.1-fold, IGF-1 increased 1.95-fold, EGF increased 1.75-fold, PDGF-BB increased 1.89-fold and TGF-beta1 increased 1.67-fold. CONCLUSION: The expression of multiple growth factors are increased in granulation tissue of refractory diabetic dermal ulcers after the treatment of APG,which might be one of the mechanism of APG to treat refractory diabetic dermal ulcer.