- A facile approach to phosphonic acid diesters
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A effective method to prepare symmetric H-phosphonate diesters of carbohydrates was presented. The phosphoramidate method, H-phosphonate method and condendation of phosphonic acid and hydroxy compounds by dicyclohexycarbodiimide were reported for the synthesis of symmetric H-phosphonates. It was found that after the pyridine was removed under pressure, the products were obtained in purity of >95%.
- Xiao, Qiang,Ju, Yong,Zhao, Yufen
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- New amphiphilic N-phosphoryl oligopeptides designed for gene delivery
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Gene therapy is a potent tool for the treatment of cancer and other gene defect diseases, which involves using DNA that encodes a functional, therapeutic gene to replace a mutated gene. However, the DNA transfection efficiency is restricted by its negative charges and low susceptibility to endonucleases which prevent them penetrating tissue and cellular membranes. Both viral and non-viral vectors have been used for gene delivery, but the former are limited by their immunogenicity, while the latter are less efficient than their viral counterpart. Cationic amphiphilic lipopeptides whose structures can be easily modified and transformed have been used as non-viral vectors in gene delivery system due to their low cytotoxicity and high transfection efficiency. In this study, a series of cationic amphiphilic N-phosphoryl oligopeptides with varied lengths of hydrophobic tails and oligopeptide headgroups (C12-K6, C14-K6, C16-K6, Chol-K6 and C12-H6) were synthesized and used as gene delivery vectors. The affinities, abilities to condense pDNA and transfection efficiencies of the K6-lipopeptides were better than those of the H6-lipopeptides. In addition, the hydrophobic chains of the lipopeptides also affected their transfection efficiencies. The K6-lipopeptide with a hydrophobic chain of twelve carbons (C12-K6) showed the highest transfection efficiency in all these synthetic lipopeptides. At an optimal P/N ratio of 20, C12-K6 showed comparable pDNA transfection efficiency to PEI-25k, a well-defined gene delivery vector, but the cytotoxicity of C12-K6 was much lower. With acceptable gene transfection efficiency and low cytotoxicity, this cationic amphiphilic lipopeptide will have promising applications in gene therapy.
- Sun, Yunfei,Chen, Long,Sun, Fude,Tian, Xibo,Luo, Shi-Zhong
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- GELLED HYDROCARBONS FOR OILFIELD PROCESSES, PHOSPHATE ESTER COMPOUNDS USEFUL IN GELLATION OF HYDROCARBONS AND METHODS FOR PRODUCTION AND USE THEREOF
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Phosphate esters useful for gelling hydrocarbons in combination with a metal source are disclosed along with methods of preparation of the phosphate esters. Fouling in oil refinery towers has been attributed due to distillation of impurities present in phosphate esters used to gel hydrocarbons for oil well fracturing. The improved method of preparation of the phosphate ester results in a product that substantially reduces or eliminates volatile phosphorus, which is phosphorus impurities that distill up to 250° C., and increases the high temperature viscosity of the hydrocarbon gels formed using the phosphate esters.
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Page/Page column 8
(2011/04/14)
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- Synthesis of AZT 5′-O-hydrogen phospholipids and their derivatives
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A series of AZT 5′-O-hydrogen phospholipids 5a-e were synthesized by a tandem transesterification of diphenyl phosphite (DPP) with AZT and a long-chain alcohol. This method has the merits of easy operation and high yields. The corresponding phosphonates, phosphorothionates and phosphoroselenoates of 5d and 5e and the phosphoramidates conjugated with L-amino acid methyl ester 9a and 9b were also synthesized.
- Xiao, Qiang,Sun, Jing,Sun, Qi,Ju, Yong,Zhao, Yu-fen,Cui, Yu-xin
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p. 107 - 111
(2007/10/03)
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- Novel approach to the synthesis of AZT 5′-O-hydrogen phospholipids
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A series of AZT 5′-O-hydrogen phospholipids were synthesized by a tandem transesterification of diphenyl phosphite with AZT and a long-chain alcohol. The method possesses the merits of ease of operation and high yields. It can also be extended to synthesize other biological phospholipids.
- Xiao, Qiang,Sun, Jing,Ju, Yong,Zhao, Yu-Fen,Cui, Yu-Xin
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p. 5281 - 5283
(2007/10/03)
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- Synthesis of N-phosphoamino Acids With Long Dialkoxyl Chains
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In this paper, a series of N-phosphoamino acids with long dialkoxyl chains were synthesized with phosphites and amino acid esters. The data of these compounds were given.
- Deng, Chang-Hui,Li, Yan-Mei,Xu, Ning,Zhao, Yu-Fen
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p. 2552 - 2560
(2007/10/03)
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- A SIMPLE AND CONVENIENT SYNTHESIS OF 2-PHOSPHONOMETHYL PYRIDINES
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The Michaelis-Becker-Nylen reaction is well suited for the synthesis of 2-phosphonomethyl pyridines.We have improved this four steps method in a one pot reaction using commercial reagents.By this general procedure we have prepared seven new 2-phosphonomethyl pyridines (Ia-g) under mild conditions with higher yields.Key words: 2-phosphono pyridines; 2-phosphonomethyl pyridines; Michaelis-Becker-Nylen reaction; new phosphonates; potential ligands.
- Page, Patrick,Mazieres, Marie-Rose,Bellan, Jacques,Sanchez, Michel
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p. 205 - 210
(2007/10/02)
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