A formal synthesis of the natural growth promoting steroid brassinolide is described,which involves construction of side chain by 1,3-sulfoxide-hydroxyl transposition with methylation from(24S)- 22-E-24-sulfoxide 6 an...A formal synthesis of the natural growth promoting steroid brassinolide is described,which involves construction of side chain by 1,3-sulfoxide-hydroxyl transposition with methylation from(24S)- 22-E-24-sulfoxide 6 and(24R)-22-E-24-sulfoxide 9,respectively to (22S)-23-E-24-methyl compound 4.展开更多
The first total synthesis of a novel phenalenone diterpene salvilenone (1) isolated from a- traditional Chinese medicine, Dan-Shen (Salvia miltiorrhiza.L.), has been achieved in thirteen steps started from resorcinol ...The first total synthesis of a novel phenalenone diterpene salvilenone (1) isolated from a- traditional Chinese medicine, Dan-Shen (Salvia miltiorrhiza.L.), has been achieved in thirteen steps started from resorcinol dimethyl ether(5).展开更多
The reaction of isopropenyl carbinol(2)with aqueous hydrobromic acid and hydroiodic- acid gave salvilenone(1)and naphthopyranone(3)respectively.The reaction mechanism has been investigated.The formation of(3)was under...The reaction of isopropenyl carbinol(2)with aqueous hydrobromic acid and hydroiodic- acid gave salvilenone(1)and naphthopyranone(3)respectively.The reaction mechanism has been investigated.The formation of(3)was undergone a novel rearrangement of a tetrahydrophenalenone to a naphthopyranone.展开更多
6,7-Methylenedioxy-3-thia-1(2H,4H)acridone and the related acridine-fused quinolines and pyridines,and also their flavylium-perchlorates were synthesized.The structures of all these compounds prepared are characterize...6,7-Methylenedioxy-3-thia-1(2H,4H)acridone and the related acridine-fused quinolines and pyridines,and also their flavylium-perchlorates were synthesized.The structures of all these compounds prepared are characterized by elemental analysis.IR and H-NMR spectra.展开更多
Cellulose tris(4-methylphenylcarbamate), amylosetris(3,5-di-methylphenylcarbamate) and amylose tris (phenylcarbamate) were prepared by the methodreported by Okamoto and were coated onto an aminopropylated mesoporous s...Cellulose tris(4-methylphenylcarbamate), amylosetris(3,5-di-methylphenylcarbamate) and amylose tris (phenylcarbamate) were prepared by the methodreported by Okamoto and were coated onto an aminopropylated mesoporous spherical silica gel. Thesefinal products were used as chiral stationary phases of high performance liquid chromatography forthe eighteen structurally related biphenyl compounds. The resolution was made using normal-phasemethodology with a mobile phase consisting of n-hexane-alcohol (ethanol, 1-propanol, 2-pro-panol or1-butanol). The effects of various aliphatic alcohols in the mobile phase were studied. Thestructural features of the solutes that influence then- k′ were discussed. A dominant effect oftrifluoroacetic acid on chiral separation of acidic solutes was noted.展开更多
A highly selective and stability-indicating HPLC-method, combined with appropriate sample preparation steps, is developed for β-artemether assay and profiling of related impurities, including possible degradants, in ...A highly selective and stability-indicating HPLC-method, combined with appropriate sample preparation steps, is developed for β-artemether assay and profiling of related impurities, including possible degradants, in a complex powder for oral suspension. Following HPLC conditions allowed the required selectivity： a Prevail organic acid （OA） column （250 mm＆#215;4.6 mm, 5μm）, flow rate set at 1.5 mL/min combined with a linear gradient （where A ？ 25 mM phosphate buffer （pH 2.5）, and B ？ acetonitrile） from 30% to 75% B in a runtime of 60 min. Quantitative UV-detection was performed at 210 nm. Acetonitrile was applied as extraction solvent for sample preparation. Using acetonitrile-water mixtures as extraction solvent, a compartmental behaviour by a non-solving excipient-bound fraction and an artemether-solubilising free fraction of solvent was demonstrated, making a mobile phase based extraction not a good choice. Method validation showed that the developed HPLC-method is considered to be suitable for its intended regulatory stability-quality characterisation of β-artemether paediatric formulations. Furthermore, LC-MS on references as well as on stability samples was performed allowing identity confirmation of the β-artemether related impurities. MS-fragmentation scheme of β-artemether and its related substances is proposed, explaining the m/z values of the in-source fragments obtained.展开更多
文摘A formal synthesis of the natural growth promoting steroid brassinolide is described,which involves construction of side chain by 1,3-sulfoxide-hydroxyl transposition with methylation from(24S)- 22-E-24-sulfoxide 6 and(24R)-22-E-24-sulfoxide 9,respectively to (22S)-23-E-24-methyl compound 4.
文摘The first total synthesis of a novel phenalenone diterpene salvilenone (1) isolated from a- traditional Chinese medicine, Dan-Shen (Salvia miltiorrhiza.L.), has been achieved in thirteen steps started from resorcinol dimethyl ether(5).
文摘The reaction of isopropenyl carbinol(2)with aqueous hydrobromic acid and hydroiodic- acid gave salvilenone(1)and naphthopyranone(3)respectively.The reaction mechanism has been investigated.The formation of(3)was undergone a novel rearrangement of a tetrahydrophenalenone to a naphthopyranone.
文摘6,7-Methylenedioxy-3-thia-1(2H,4H)acridone and the related acridine-fused quinolines and pyridines,and also their flavylium-perchlorates were synthesized.The structures of all these compounds prepared are characterized by elemental analysis.IR and H-NMR spectra.
文摘Cellulose tris(4-methylphenylcarbamate), amylosetris(3,5-di-methylphenylcarbamate) and amylose tris (phenylcarbamate) were prepared by the methodreported by Okamoto and were coated onto an aminopropylated mesoporous spherical silica gel. Thesefinal products were used as chiral stationary phases of high performance liquid chromatography forthe eighteen structurally related biphenyl compounds. The resolution was made using normal-phasemethodology with a mobile phase consisting of n-hexane-alcohol (ethanol, 1-propanol, 2-pro-panol or1-butanol). The effects of various aliphatic alcohols in the mobile phase were studied. Thestructural features of the solutes that influence then- k′ were discussed. A dominant effect oftrifluoroacetic acid on chiral separation of acidic solutes was noted.
基金funded by PhD grants of "Institute for the Promotion of Innovation through Science and Technology in Flanders (IWT-Vlaanderen)" (nos. 110533 and 101529)
文摘A highly selective and stability-indicating HPLC-method, combined with appropriate sample preparation steps, is developed for β-artemether assay and profiling of related impurities, including possible degradants, in a complex powder for oral suspension. Following HPLC conditions allowed the required selectivity： a Prevail organic acid （OA） column （250 mm＆#215;4.6 mm, 5μm）, flow rate set at 1.5 mL/min combined with a linear gradient （where A ？ 25 mM phosphate buffer （pH 2.5）, and B ？ acetonitrile） from 30% to 75% B in a runtime of 60 min. Quantitative UV-detection was performed at 210 nm. Acetonitrile was applied as extraction solvent for sample preparation. Using acetonitrile-water mixtures as extraction solvent, a compartmental behaviour by a non-solving excipient-bound fraction and an artemether-solubilising free fraction of solvent was demonstrated, making a mobile phase based extraction not a good choice. Method validation showed that the developed HPLC-method is considered to be suitable for its intended regulatory stability-quality characterisation of β-artemether paediatric formulations. Furthermore, LC-MS on references as well as on stability samples was performed allowing identity confirmation of the β-artemether related impurities. MS-fragmentation scheme of β-artemether and its related substances is proposed, explaining the m/z values of the in-source fragments obtained.
