ABSTRACT
As a minimally invasive method, endovascular embolization has been an effective strategy for controlling bleeding and tumor treatment. Herein, carboxymethyl chitin embolic microspheres were prepared with the aqueous two-phase carboxymethyl chitin/polyethylene glycol system without using any crosslinking agents and thrombin-functionalized embolic microsphere named as Thr@CMCHm-30 was made after covalent introduction of thrombin. The size of the microspheres can be adjusted from 5 to 500 µm. The data of in vitro and in vivo tests indicated that these microspheres possessed good degradability and biocompatibility. Meanwhile, Thr@CMCHm-30 can significantly promote blood clotting and enhance the strength of the blood clots. More importantly, Thr@CMCHm-30 displayed better embolization effect than that of the commercial available Gelfoam Alicon® and polyvinyl alcohol-based embolic microspheres CalliSpheres® in rat femoral vein and rabbit ear artery embolization models. Therefore the size-tunable and biodegradable thrombin-functionalized carboxymethyl chitin microspheres Thr@CMCHm-30 possess great potential for effective hemostasis and endovascular embolization.
Subject(s)
Chitin , Thrombin , Animals , Hemostasis , Microspheres , Polyvinyl Alcohol , Rabbits , RatsSubject(s)
Avitaminosis/history , Nutritional Sciences/history , Animals , Avitaminosis/prevention & control , China , Diabetes Mellitus/history , Diabetes Mellitus/prevention & control , History, 20th Century , Humans , Neoplasms/history , Neoplasms/prevention & control , Neurodegenerative Diseases/history , Neurodegenerative Diseases/prevention & controlABSTRACT
An efficient copper-catalyzed selective cross coupling of imidazo[1,2-a]pyridines with methyl hetarenes has been reported. This transformation opened a new route to synthesize the C-3 carbonyl imidazo[1,2-a]pyridine derivative, which is a common structural motif in natural products and pharmaceuticals. (18)O-labeling experiments indicated that the oxygen source of products originated from O2.
ABSTRACT
A novel copper-catalyzed regioselective double carbonylation of imidazo[1,2-a]pyridines with N,N-disubstituted acetamide or acetone using molecular oxygen has been described. It has provided a new approach to synthesize 1,2-carbonyl imidazo[1,2-a]pyridines, which are important substrates and intermediates in preparation of fine chemicals. The product shares a skeleton similar to that of Zolpidem, one of the most prescribed drugs in the world. (18)O-labeling experiments unambiguously established that the oxygen source of products originated from O2 rather than H2O.
ABSTRACT
Using the widely available DMSO as the formylation reagent under oxidative conditions, an efficient Cu-catalyzed C3-formylation reaction of imidazo[1,2-a]pyridine C-H bonds to directly generate structurally sophisticated 3-formyl imidazo[1,2-a]pyridine derivatives has been developed. The reaction proceeded to generate products in good yields, and used the environmentally friendly molecular oxygen as the oxidant.