排序方式: 共有19条查询结果,搜索用时 15 毫秒
1.
M. Meisel 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-4):137-140
Abstract Some new results, especially on the fluoride degradation of phosphorus sulfides and phosphorus oxide sulfide are reported. Possible reaction mechanisms are discussed. 相似文献
2.
Ryszard Andruszkiewicz Ewa Liedke-Przybysz 《Phosphorus, sulfur, and silicon and the related elements》2013,188(12):2274-2278
Abstract Reaction of succinimide with diphenylchlorophosphate in the presence of lithium bis(trimethylsilyl)amide followed by aqueous work-up led to the formation of amidophosphate 3. The same reaction performed in the presence of sodium hydride yield N-(diphenylphosphoryl)succinimde 4, which undergoes nucleophilic ring opening with sodium alkoxides resulted in the formation of phosphoroamidate analogues 5 a-d in good yields. GRAPHICAL ABSTRACT 相似文献
3.
Leandro F. Pedrosa William P. de Macedo Antonia C. R. Furtado Guilherme P. Guedes Luiz C. S. Pinheiro Jackson A. L. C. Resende 《合成通讯》2013,43(24):3373-3386
New thieno[2,3-b]pyridine phosphoramidates compounds were synthesized and characterized by infrared; 1H, 13C, and 31P NMR spectroscopy; and high-resolution mass spectrometry. The products were obtained in good yields (64–82%) under mild conditions by nucleophilic aromatic substitution reaction of aminoalkylphosphoramidates over 4-chlorothieno[2,3-b]pyridine-5-carbonitrile. The crystal structures of two compounds were solved by x-ray diffraction and showed a network of intermolecular interactions involving phosphoramidate groups. Druglike properties and toxicity of the new compounds were studied with the help of the software Molinspiration, Osiris, and Toxtree, and were compared with the standard drugs amphotericin B, miltefosine, benznidazole, and nifurtimox. [Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.] 相似文献
4.
5.
Several amino acid ester cyclohexyl phosphoramidates of AZT as anti-HIV prodrugs were synthesized and investigated by electrospray ionization tandem mass spectrometry (ESI-MS(n)). A novel methoxy group migration from the carbonyl group to the phosphoryl group was observed in ESI-MS2. This migration is believed to be a general pathway for ions with a methyl ester moiety at the gamma-position to a phosphoric acid moiety, which is assisted with metal ions such as Li(+), Na(+) and K(+). Coordination between metal ions with both the carbonyl oxygen and phosphoryl oxygen might be a key factor responsible for this migration. 相似文献
6.
J. S. Pizey K. Symeonides 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1):41-45
Abstract Isopropyl β-ketosulfinyl chlorides may be prepared in high yields by treating the appropriate isopropyl ketone with thionyl chloride under mild conditions. β-Ketosulfinyl chlorides do not appear to have been previously reported in the literature. Analytical and spectral data indicate that in cases where α and α' protons are adjacent to the carbonyl group only the α-proton of the isopropyl group is substituted giving a monosulfinyl chloride. In certain cases where the α'-proton is activated cyclization and reduction may occur to give the substituted thietan-3-one. Comparable chloro-compounds have been prepared by treating the ketone with sulfuryl chloride. Anomalous nmr spectra obtained for certain compounds have been further studied using variable temperature techniques and various solvents. An attempt was made to prepare the β-ketosulfinamides, and the compounds obtained were found to be unstable. 相似文献
7.
Dr. Mo Wang Lu Zhang Dr. Xiaohong Huo Dr. Zhenfeng Zhang Dr. Qianjia Yuan Panpan Li Dr. Jianzhong Chen Yashi Zou Dr. Zhengxing Wu Prof. Dr. Wanbin Zhang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(47):21000-21005
The catalytic asymmetric synthesis of the anti-COVID-19 drug Remdesivir has been realized by the coupling of the P-racemic phosphoryl chloride with protected nucleoside GS441524. The chiral bicyclic imidazole catalyst used is crucial for the dynamic kinetic asymmetric transformation (DyKAT) to proceed smoothly with high reactivity and excellent stereoselectivity (96 % conv., 22:1 SP:RP). Mechanistic studies showed that this DyKAT is a first-order visual kinetic reaction dependent on the catalyst concentration. The unique chiral bicyclic imidazole skeleton and carbamate substituent of the catalyst are both required for the racemization process, involving the phosphoryl chloride, and subsequent stereodiscriminating step. A 10 gram scale reaction was also conducted with comparably excellent results, showing its potential for industrial application. 相似文献
8.
9.
10.
To obtain detailed data on the kinetics of hydrolytic reactions of triester-like nucleoside 5'-O-aryl-N-alkylphosphoramidates, potential prodrugs of antiviral nucleoside monophosphates, the hydrolysis of diastereomeric (Rp/Sp) thymidine 5'-{O-phenyl-N-[(1S)-2-oxo-2-methoxy-1-methylethyl]phosphoramidate} (3), a phosphoramidate derived from the methyl ester of L-alanine, has been followed by reversed-phase HPLC over the range from Ho=0 to pH 8 at 90 degrees C. According to the time-dependent product distributions, the hydrolysis of 3 proceeds at pH<4 by two parallel routes, namely by nucleophilic displacement of the alaninyl ester moiety by a water molecule and by hydrolysis of the carboxylic ester linkage that allows intramolecular attack of the carboxy group on the phosphorus atom, thereby resulting in the departure of either thymidine or phenol without marked accumulation of any intermediates. Both routes represent about half of the overall disappearance of 3. The departure of phenol eventually leads to the formation of thymidine 5'-phosphate. At pH>5, the predominant reaction is hydrolysis of the carboxylic ester linkage followed by intramolecular displacement of a phenoxide ion by the carboxylate ion and hydrolysis of the resulting cyclic mixed anhydride into an acyclic diester-like thymidine 5'-phosphoramidate. The latter product accumulated quantitatively without any indication of further decomposition. Hydroxide-ion-catalyzed P--OPh bond cleavage of the starting material 3 occurred as a side reaction. Comparative measurements with thymidine 5'-{N-[(1S)-2-oxo-2-methoxy-1-methylethyl]phosphoramidate} (4) revealed that, under acidic conditions, this diester-like compound is hydrolyzed by P--N bond cleavage three orders of magnitude more rapidly than the triester-like 3. At pH>5, the stability order is reversed, with 3 being hydrolyzed six times as rapidly as 4. Mechanisms of the partial reactions are discussed. 相似文献