Synthesis of carbapenem skeleton / 国际药学研究杂志

Objective To investigete a new synthetic route for carbapenem skeleton(1)for industrial production. Methods (3S,4R)-4-acetoxy-3-[(1R)-(tert-butyldimethylsilyloxy)ethyl]azetidin-2-one(4-AA)was used as raw material,and 1 was obtained from it through a homemade chiral auxiliary zinc powder catalyzed Reformatsky reaction,hydrolysis,the introduction of β-carboxyl es?ter structure,deprotection,cyclization,and activation by diphenyl chlorophosphate. The each key process was optimized,and the structures of intermediate and target compounds were confirmed by MS,GC-MS and 1H NMR.Results and Conclusion The total yield was 19.9%.The improved process conditions are mild,easy to operate,and suitable for industrial production.

Effects of Mailuoning to Excitatory Amino Acid and Nitric Oxi de Synthase in Cerebral Cortex of Neonatal Sprague-Dawely Rats after Hypoxia-I schemia / 实用儿科临床杂志

Objective To study changes of aspartate(ASP) and glutamaic acid(GLU) in cerebral cortex of neonatal Sprague-Dawely(SD) rats after hypoxia-ischemia and nitric oxide synthase(NOS) immunoactive expression in cerebral neurons were examined to explore mailuoning′s protective effect on hypoxia-ischemia brain damage(HIBD).Methods The HIBD model was established as follows.The right common carotids of the neonatal SD rats 7 days were temporaily ligatured for 1 hour.Then the neonatal SD rats were exposed to 8% oxygen and 92% nitrogen gas mixture for 2 hours. The ASP and GLU were determined in right cerebral cortex using chromatograph,compared with sham-operated group and mailuoning administrated. Ultrastructure changes of neurons in the right cerebral cortex of neonatal SD rats were observed after sham-operated,hypoxia-ischemia and mailuoning administrated using electronmicroscope.Results The level of excitatory amino acid was promoted in right cerebral cortex after hypoxia-ischemia.The volume of excitatory amino acid was reduced sharply mailuoning administrated. Ultrastructure of neurons in the cerebral cortex showed serious injure after hypoxia-ischemia and ultrastructure of neurons in the cerebral cortex appeared slight damage.Conclusion Mailuoning may possess protective effects to the neurons after hypoxia-ischemia through supplying blood to neurons reducing release of excitatory amino acid.