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1.
Alkyl (2-dimethylamino)ethyl methyl phosphates are prepared and isomerize smoothly to the corresponding alkyl choline phosphates.  相似文献   

2.
A group of crystalline and amorphous calcium-magnesium phosphates were prepared by exchange in solution of sodium orthophosphate and calcium and magnesium chlorides at pH 8-12. The behavior of the phosphates on heating to 1000°C was studied.  相似文献   

3.
Some sugar phosphates, phosphonates and phosphine oxides, Preliminary communication Some new phosphates of 1, 2-O-isopropylidene-α-D-ribofuranose have been prepared. Reactions of 3-C-cyanomethylidene-3-deoxy-1, 2-O-isopropylidene-5-O-trityl-α-D -erythro-pentofuranose (9) have been studied. On treatment with phosphorus nucleophiles, 9 led to phosphorus bearing branched-chain sugar derivatives. Branched-chain cyanosugars as 15 and 16 prepared by cis-vic-dihydroxylation of 9 constitute interesting potential precursors of new types of cyclic sugar phosphates.  相似文献   

4.
Differentially protected glycosyl phosphates prepared by a straightforward synthesis from glycal precursors are used as powerful glycosyl donors. Activation of beta-glycosyl phosphates by TMSOTf at -78 degrees C achieves the selective formation of beta-glycosidic linkages in excellent yields with complete stereoselectivity. Reaction with thiols results in the conversion of glycosyl phosphates into thioglycosides in nearly quantitative yield. An orthogonal coupling strategy using glycosyl phosphate donors and thioethyl glycoside acceptors allows for the rapid synthesis of a trisaccharide.  相似文献   

5.
Cyanohydrin phosphates 2a–2c were prepared in high yield from ketones (or aldehyde), diethyl phosphorochloridate, and sodium cyanide by using acetonitrile as solvent. GC analysis proved that the two reactions of cyanohydrin sodium with diethyl phosphorochloridate and with diethyl phosphorocyanidate resulted in the formation of cyanohydrin phosphates.  相似文献   

6.
磷酸锆催化甘油气相脱水制备丙烯醛   总被引:3,自引:0,他引:3  
以沉淀法、水热合成法和浸渍法制备了磷酸锆催化剂,通过X射线衍射、热重分析、氮气物理吸附、红外光谱和Hammett指示剂法对催化剂进行了表征,并将该催化剂用于甘油气相脱水反应.研究表明,由沉淀法得到的磷酸锆经过400℃焙烧后能达到最佳催化活性,在温和条件下,甘油可完全转化,丙烯醛选择性为81%,反应24h内催化剂失活不明显.不同方法制备的磷酸锆其结构和表面酸性显著不同,催化剂表面酸性对催化剂活性、丙烯醛选择性和催化剂的寿命均有较大影响.  相似文献   

7.
Copper-catalyzed γ-selective coupling between propargylic phosphates and alkylboron compounds (alkyl-9-BBN, prepared by hydroboration of alkenes with 9-BBN-H) affords multisubstituted allenes with various functional groups. The reaction of enantioenriched propargylic phosphates to give axially chiral allenes proceeds with excellent point-to-axial chirality transfer with 1,3-anti stereochemistry.  相似文献   

8.
应用固-液相转移催1化方法合成肌醇磷酸脂   总被引:1,自引:0,他引:1  
丁贻祥  周顺福  沈瑾 《化学学报》1995,53(3):305-309
固-液相转移催化方法已成功地应用于各种肌醇磷酸脂的合成.在固- 液相转移催化条件下,肌醇衍生物O-烷基化的选择性得到了有效的改进;而在固- 液相转移催化条件下的atheron-todd反应,为肌醇衍生物的磷酰化提供了一个良好的新方法.  相似文献   

9.
Amorphous acidic metal(IV) phosphates of zirconium, titanium and tin have been prepared and hydrogen-exchanged for bivalent Pd, Pt and Ni. These bivalent metals were returned to the zero valent state by reducing them with either hydrogen at 400 °C or with sodium tetrahydroborate at room temperature. The resulting Pd0, Pt0 and Ni0 phosphates were investigated as selective catalysts for heterogeneous hydrogenation of alkenes in solution at normal temperatures and pressures and, for Ni, also in the vapour phase. Quantitative studies on rates of hydrogenation are discussed. The usual methods for preparing metal(IV) phosphates give either crystalline or amorphous solids having low specific surfaces areas. A method has been developed, by which metal(IV) phosphates having large surface areas (lsa) may be prepared easily. These lsa supports take up large amounts of transition metal cations by simple exchange. The enhanced incorporation of Pd, Pt or Ni and increases in surface areas of the phosphate supports have provided some active, selective catalysts. Pd/Ti phosphates were the most active and compared well with commercial Pd on carbon. Ni/Ti phosphate is a very selective catalyst for vapour phase hydrogenation of alkenes and, at slightly higher temperatures, it is an efficient hydrocarbon cracking catalyst.  相似文献   

10.
o- and p-Trifluoromethylphenyl phosphates designed as mechanism-based phosphotyrosine phosphatase inactivators have been prepared. Some of them show herbicidal activities.  相似文献   

11.
The ion exchange technique was employed for the preparation of VO2+ modified titanium phosphates as catalysts for the selective reduction of NO with NH3. The samples were prepared by contacting with a vanadyl sulphate solution different precursor materials, amorphous, crystalline or sodium half exchanged titanium phosphate. The vanadium contents of modified phosphates were in the range 0.08–2.3 wt%. XRD and thermal analysis TG/DTA showed that vanadium loading does not cause structural modification in hydrogen titanium phosphate. A vanadyl containing phase was obtained when half sodium titanium phosphate was employed. The NH3 TPD measurements indicated the presence of a wide distribution of NH3 adsorbing sites with medium-high strength. Catalytic activity measurements were performed under dilute conditions. It was found that the presence of vanadium even in low amounts strongly promote the catalytic activity.  相似文献   

12.
Abstract

A number of diphenyl α-glucopyranosyl and xylopyranosyl phosphates (4, 7, 11. 15, 19, and 25) were prepared from their respective glycosyl chlorides by reaction with silver diphenyl phosphate. These sugar phosphates are of interest as enzyme substrates in deoxy sugar biosynthesis.  相似文献   

13.
The use of highly active manganese, prepared by the Rieke method, for the direct preparation of benzylic manganese reagents was investigated. The oxidative addition of the highly active manganese (Mn) to benzylic halides was easily completed under mild conditions. More importantly, benzylic manganese sulfonates and phosphates were prepared by direct oxidative addition of Mn to the carbon-oxygen bonds of benzylic sulfonates and phosphates. The resulting benzylic manganese reagents were found to undergo cross-coupling reactions with a variety of electrophiles. The majority of these reactions were carried out in the absence of any transition metal catalyst under mild conditions. This approach also provided a facile synthetic route to the preparation of resorcinolic lipids.  相似文献   

14.
Dibenzylphosphates of 1-adamantanol and kemantane, 1-adamantyl phosphate, and a series of diphenyl phosphates of bridgehead alcohols have been prepared.  相似文献   

15.
[formula: see text] A beta-(1-->4)-linked trisaccharide was prepared in 53% yield on a polymer support using glycosyl phosphates and released by cross-metathesis of a novel linker to reveal the anomeric n-pentenyl glycoside. Heptasaccharide 33 was prepared in 9% yield in 14 steps.  相似文献   

16.
《Tetrahedron letters》1986,27(36):4265-4268
Enol phosphates, readily prepared from ketone enolates and dialkyl phosphorochloridate, can be converted to the analogous β-ketophosphonates by treatment with strong base.  相似文献   

17.
1-Alkynylphosphonates 4 are prepared by the in situ β-elimination of enol phosphates 3, which are readily generated by the reaction of sodium enolate of 2-oxophosphonate with diethyl chlorophosphate.  相似文献   

18.
Organocopper-mediated anti-SN2' reactions of gamma-phosphoryloxy-alpha,beta-unsaturated-delta-lactams were used to prepare highly functionalized diketopiperazine mimetics. The substrate phosphates 24, 32, and 47 were prepared from alpha-amino acid-derived allylic alcohols 10 by a sequence of reactions that included ring-closing metathesis. In the reactions of phosphates with organocopper reagents, the addition of LiCl dramatically improved anti-SN2' selectivity, indicating that an organocopper cluster containing lithium chloride plays an important role in the determination of regioselectivity. This reaction system was applied to the preparation of novel low molecular weight CXCR4-chemokine receptor antagonists.  相似文献   

19.
Novel iron phosphates microflowers which show SOD-like and peroxidase-like mimic activities were prepared, suggesting potential applications as a biocatalyst and a biosensor for H(2)O(2).  相似文献   

20.
Optically active bis(homoallenyl)amines bearing two chiral axes with the same sense of axial chirality were prepared by a one-pot, palladium-catalyzed sequential homoallenylation of primary amines with 2,3-allenyl phosphates.  相似文献   

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