通过共价限制多个手性Salen Ti IV制备了一系列新的树枝状手性Salen Ti IV催化剂。通过柔性离子液体(IL)接头在聚酰胺酰胺(PAMAM)树状大分子的外围形成复合物。表征结果表明在催化剂中存在树枝状PAMAM支架,IL间隔基和完整的外围活性位。催化剂独特的树枝状结构与灵活的IL间隔基共同增强了不对称硫氧化的分子内协同催化作用,从而提高了催化效率,尤其是显着高的选择性。在树枝状催化剂催化的甲基苯基硫醚的不对称硫氧化反应中,化学选择性为90%,对映选择性为85%,明显高于纯配合物(64%的化学选择性和68%的对映选择性)。此外,
An efficient aza-Michael addition of amines to a variety of activated olefins was carried out under solvent free conditions using iodine-alumina as a catalyst at room temperature or under microwave irradiation (in case of solid) in high yield.
作者:Hala S. Abd El-Haleem、Amr Hefnawy、Rabeay Y. A. Hassan、Ashraf H. Badawi、Ibrahim M. El-Sherbiny
DOI:10.1039/c6ra24419j
日期:——
In this study, the synthesis, characterization and testing of new polymeric–metal oxide nanocomposites for enzymatic glucose biosensors were performed.
Abstract A series of novel hindered amine light stabilizers (HALSs) containing four hindered amine groups were designed and synthesized from diamines, methyl acrylate, and 2,2,6,6-pentamethyl-piperidine-4-ol through Michael addition and transesterification. The structures of target compounds were confirmed by 1H NMR and 13C NMR. Two of them were chosen to be evaluated for their antioxidation and anti-aging
METHOD FOR SEPARATING FLAVONOID SUBSTANCES IN CAMELLIA NITIDISSIMA CHI BASED ON A MAGNETIC NANOPARTICLES-PAMAM NANO COMPOSITES
申请人:Shenzhen Violin Technology Co.,Ltd.
公开号:US20160137623A1
公开(公告)日:2016-05-19
The present invention discloses a method for separating flavonoid substances in
Camellia nitidissima
Chi based on a magnetic nanoparticles-PAMAM nano composites, which comprises the following steps: preparing PAMAM dendrimer, then using the PAMAM dendrimer to prepare the magnetic nanoparticles-PAMAM nano composites, then adding the obtained magnetic nanoparticles-PAMAM nano composites in a
Camellia nitidissima
Chi extract, extracting and performing magnetic separation on the flavonoid substances in
Camellia nitidissima
Chi under ultrasound or microwave condition. According to the present invention, flavonoid substances with faintly acid characteristics are extracted and adsorbed in a plant concentrate such as
Camellia nitidissima
Chi or
Hedyotis diffusa
etc. based on the magnetic nanoparticles-PAMAM nano composites, in a successive step, high efficiency separation of the flavonoid substances can be realized by the technologies such as magnetic separation and microwave-assisted extraction.
Efficient oral insulin delivery by dendronized chitosan: in vitro and in vivo studies
作者:Piyasi Mukhopadhyay、Kishor Sarkar、Sourav Bhattacharya、Roshnara Mishra、P. P. Kundu
DOI:10.1039/c4ra07511k
日期:——
The development of efficient and bio-safe polymeric carriers for oral insulin delivery is a major thrust in biomedical research. In this paper, dendronized chitosan (DCTS) is prepared using a Michael-type addition reaction by grafting polyamidoamine (PAMAM) onto chitosan to improve its water solubility, pH sensitivity, and insulin encapsulation efficiency for enhanced bioavailability of the oral insulin. The self-assembled dendronized chitosan nanoparticles are prepared using a mild coacervation method, in which almost sub-spherically shaped nanoparticles of 85–150 nm size are produced, with an insulin encapsulation of approx. 95%. In vitro release study confirms a pH-sensitive and self-sustained release of insulin, where the oral administration of these nanoparticles exhibits a pronounced hypoglycemic effect in diabetic mice, producing a relative bioavailability of ∼9.19%. As no systemic toxicity is observed with its peroral delivery, these DCTS nanoparticles can effectively serve as a promising device in the efficient administration of oral insulin.