To valorize further the highly valuable bio-based platform (S)-γ-hydroxymethyl-γ-butyrolactone (2H-HBO), whose sustainable kiloscale-synthesis from cellulose-derived levoglucosenone (LGO) has been validated, a mechanochemical strategy was developed to produce new potential bio-based surfactants under solventless conditions. First, the reaction of 2H-HBO with primary or secondary amines was investigated followed by a sulfation reaction with the isolated N-alkyl-amide derivatives to obtain the corresponding N-alkyl sulfated compounds. The latter was then obtained by an optimized one-pot sequential aminolysis–sulfation in a planetary ball mill with excellent efficiency. For the first time, sulfated compounds arising from bio-based/renewable resources were obtained exclusively via a mechanochemical process. As a result, the sulfated derivatives of 2H-HBO were formed quantitatively and isolated in 69–79% overall yields. The critical micelle concentration (CMC) was determined for some of them which exhibited interesting anionic surfactant properties.
The first copper-catalyzed aziridination of olefins using recyclable magnetic nanoparticles is described. Magnetic nanoparticles were modified with dopamine and used as a support to coordinate copper. The methodology was optimized with styrene as olefin and using [N-(p-toluenesulfonyl)imino]phenyliodinane (PhI=NTs) as nitrene source. A microwave irradiation decreased the reaction time by 4-fold compared to conventional heating method. The catalyst was recovered by simple magnetic extraction and could be reused successfully up to five times without significant loss of activity. The methodology was applied to a range of different olefins leading to moderate to excellent yields in the formation of the expected aziridine.
Bone fracture healing is a complex biological process involving four phases coordinated over time: hematoma formation, granulation tissue formation, bony callus formation, and bone remodelling. Bone fractures represent a significant health problem, particularly among the elderly population and patients with comorbidities. Therapeutic strategies proposed to treat such fractures include the use of autografts, allografts, and tissue engineering strategies. It has been shown that bone morphogenetic protein 2 (BMP-2) has a therapeutic potential to enhance fracture healing. Despite the clinical efficacy of BMP-2 in osteoinduction and bone repair, adverse side effects and complications have been reported. Therefore, in this in vitro study, we propose the use of a disaccharide compound (DP2) to improve the mineralisation process. We first evaluated the effect of DP2 on primary human osteoblasts (HOb), and then investigated the mechanisms involved. Our findings showed that (i) DP2 improved osteoblast differentiation by inducing alkaline phosphatase activity, osteopontin, and osteocalcin expression; (ii) DP2 induced earlier in vitro mineralisation in HOb cells compared to BMP-2 mainly by earlier activation of Runx2; and (iii) DP2 is internalized in HOb cells and activates the protein kinase C signalling pathway. Consequently, DP2 is a potential therapeutical candidate molecule for bone fracture repair.
Background/Objectives: Delays in bone healing and complications of remodeling constitute a major medical problem—particularly in older adults and patients with comorbidities. Current therapeutic approaches are based on strategies that promote bone regeneration. We recently identified a disaccharide compound (DP2) that enhances in vitro mineralization in human osteoblast cells via the early activation of Runx2 and the induction of osteoblast differentiation. Methods: First, a calcium quantification assay was performed to assess mineralization in MC3T3-E1 cells. Next, microcomputed tomography and histological analyses were used to examine in vivo bone repair in a rat 5 mm cranial defect model following the implantation of DP2 coupled to a micro/macroporous biphasic CaP ceramic (MBCP+) or collagen scaffold. Results: Here, we demonstrated that DP2 induced osteogenic differentiation and significantly elevated calcium matrix deposition in the murine preosteoblast cell line MC3T3-E1. We found that treatment with DP2 coupled to MBCP+ repaired the calvarial defect on post-implantation day 91. It significantly increased bone mineral density starting on day 29 post-treatment. In addition, DP2 did not induce ectopic bone formation. Conclusions: Taken as a whole, these results show that DP2 is a promising candidate treatment for delayed bone healing.
This article presents the electrochemical properties of a series of phenothiazine and phenoxazine dimers, by involving an aromatic central core, efficiently synthesized in a single step through a Buckwald–Hartwig coupling reaction. A synergistic approach combining experimental and quantum chemical studies was used in view of providing a thorough characterization of their capabilities as electrodes in the context of electrochemical energy storage applications. A detailed study of the electrochemical activity was then conducted with the aim of optimizing performance, i.e., achieving a specific capacity of around 100 mAh.g −1 , close to the theoretical values at a potential of 3.6 V relative to Li metal. The dimerization strategy also emerged as an interesting methodology, since it gives rise to molecular materials having specific solubility properties. This finding opens up the possibility of recovering the active material from the electrode at the end of its life, thus paving the way for improved organic electrodes and batteries, especially with respect to their recyclable character.