The obstinated amino acid,Boc-Asn(or Boc-Gln),was directly anchored onto the Merrifield's resin using DCHA as the base in present reaction.The yield(71.88%)of Boc-Asn-OCH_2-resin was much better than those(0-33.5%...The obstinated amino acid,Boc-Asn(or Boc-Gln),was directly anchored onto the Merrifield's resin using DCHA as the base in present reaction.The yield(71.88%)of Boc-Asn-OCH_2-resin was much better than those(0-33.5%)using Cs_2CO_3,KOH,KF.DEA and TEA as the base.which are efficient reagents for other amino acids in the same reaction.展开更多
Aromatic nitro compounds were reduced to the corresponding anilines by refluxing with potassium selenated borohydride (KBH2Se3) prepared from potassium borohydride and selenium in refluxed formamide.
The electrochemi luminescence <ecl> of a new reagent 6-<2-hydroxy-4-diethylaminophenylazo>-2, 3-dihydro-1, 4-phthatazine-1, 4-dione <HDEA> in basic aqueous solution was studied. Trace amount of silve...The electrochemi luminescence <ecl> of a new reagent 6-<2-hydroxy-4-diethylaminophenylazo>-2, 3-dihydro-1, 4-phthatazine-1, 4-dione <HDEA> in basic aqueous solution was studied. Trace amount of silver showed significant effect on the efficiency of light emission of HDEA during a positive trigonometrical wave pulse was exerted on the electrodes In the present paper, the ecl spectra of HDEA have been measured. λ_(max) is 410 nm. The reaction of HDEA chemiluminescence and the circular voltammetry, ultraviolet-visible spectrometry for the system have been investigated. The possible mechanism of the ecl of HDEA-KCL-KOH-Ag(I) system has been proposed.展开更多
This paper reports the synthesis and general properties of the new reagent CPFP. Its dissociation constants have been determined. The characterization in determinating total RE with CPAP reagent has been investigated ...This paper reports the synthesis and general properties of the new reagent CPFP. Its dissociation constants have been determined. The characterization in determinating total RE with CPAP reagent has been investigated in detail. Analytic data for synthetic sample are satisfactory.展开更多
Subject Code:B02 With the support by the National Natural Science Foundation of China,the research group led by Prof.Tang Pingping(汤平平)from Nankai University reported the asymmetric and direct trifluoromethoxylatio...Subject Code:B02 With the support by the National Natural Science Foundation of China,the research group led by Prof.Tang Pingping(汤平平)from Nankai University reported the asymmetric and direct trifluoromethoxylation with trifluoromethyl aryl sulfonate(TFMS)as a new展开更多
A new convenient method for epoxidation of olefins by sodium percarbonate-acetic anhydride is reported.It is found that the epoxides in 60—80% yields can be obtained in 18—24 h without ultrasonication.However,higher...A new convenient method for epoxidation of olefins by sodium percarbonate-acetic anhydride is reported.It is found that the epoxides in 60—80% yields can be obtained in 18—24 h without ultrasonication.However,higher yields(some nearly quantitative)can be reached only within 1—3 h under ultrasonication.A comparison between the ultrasonicated epoxidations by use of sodium percarbonate and sodium perborate is also made.The experimental results have revealed that ultrasonication plays a main role in accelerating the interaction of both sodium percarbonate and sodium perborate with acetic anhydride,but it does not alter the mechanism of these two epoxidations.展开更多
-This paper first presents a new potassium reagent and efficient enrichment agent for direct recovery of potassium from seawater, i. e. , 1, 2, 4, 5-tetrahydroxybenzen -O, O' , O', O'''- tetraaceti...-This paper first presents a new potassium reagent and efficient enrichment agent for direct recovery of potassium from seawater, i. e. , 1, 2, 4, 5-tetrahydroxybenzen -O, O' , O', O'''- tetraacetic acid (TTAH4). The synthetic method of TTAH4, its enrichment behaviour for potassium ion in low concentration solution and seawater, and the chemical structure of its corresponding potassium salt have been investigated. A mechanism which caused the uptake of potassium ion is suggested. Elementary analysis and IR-spectrum determination of the potassium salt proved correct evidence for a polynuclear complex, i. e. , (TTAH3K)n. Thus, the mechanism which caused the uptake of potassium ion may be interpreted in terms of the formation of polynuclear chains as a continual sandwich type coordination complex.展开更多
The reaction of perfluoroalkyliodides,perfluoroalkylbromide,1,1, 1-trifluoro-2,2,2-trichloro-ethane,and carbon tetrachloride with thiourea dioxide in aqueous acetonitrile solution gave the corresponding sulfinate in g...The reaction of perfluoroalkyliodides,perfluoroalkylbromide,1,1, 1-trifluoro-2,2,2-trichloro-ethane,and carbon tetrachloride with thiourea dioxide in aqueous acetonitrile solution gave the corresponding sulfinate in good yield.展开更多
基金The yield was evaluated by monitoring the SD(substitution degree of Asn on the resin)value from quantitative ninhydrin test5 after due time reaction and the de-Boc treatment.
文摘The obstinated amino acid,Boc-Asn(or Boc-Gln),was directly anchored onto the Merrifield's resin using DCHA as the base in present reaction.The yield(71.88%)of Boc-Asn-OCH_2-resin was much better than those(0-33.5%)using Cs_2CO_3,KOH,KF.DEA and TEA as the base.which are efficient reagents for other amino acids in the same reaction.
文摘Aromatic nitro compounds were reduced to the corresponding anilines by refluxing with potassium selenated borohydride (KBH2Se3) prepared from potassium borohydride and selenium in refluxed formamide.
基金This work was supported by National Natural Science Foundation of China
文摘The electrochemi luminescence <ecl> of a new reagent 6-<2-hydroxy-4-diethylaminophenylazo>-2, 3-dihydro-1, 4-phthatazine-1, 4-dione <HDEA> in basic aqueous solution was studied. Trace amount of silver showed significant effect on the efficiency of light emission of HDEA during a positive trigonometrical wave pulse was exerted on the electrodes In the present paper, the ecl spectra of HDEA have been measured. λ_(max) is 410 nm. The reaction of HDEA chemiluminescence and the circular voltammetry, ultraviolet-visible spectrometry for the system have been investigated. The possible mechanism of the ecl of HDEA-KCL-KOH-Ag(I) system has been proposed.
文摘This paper reports the synthesis and general properties of the new reagent CPFP. Its dissociation constants have been determined. The characterization in determinating total RE with CPAP reagent has been investigated in detail. Analytic data for synthetic sample are satisfactory.
文摘Subject Code:B02 With the support by the National Natural Science Foundation of China,the research group led by Prof.Tang Pingping(汤平平)from Nankai University reported the asymmetric and direct trifluoromethoxylation with trifluoromethyl aryl sulfonate(TFMS)as a new
文摘A new convenient method for epoxidation of olefins by sodium percarbonate-acetic anhydride is reported.It is found that the epoxides in 60—80% yields can be obtained in 18—24 h without ultrasonication.However,higher yields(some nearly quantitative)can be reached only within 1—3 h under ultrasonication.A comparison between the ultrasonicated epoxidations by use of sodium percarbonate and sodium perborate is also made.The experimental results have revealed that ultrasonication plays a main role in accelerating the interaction of both sodium percarbonate and sodium perborate with acetic anhydride,but it does not alter the mechanism of these two epoxidations.
文摘-This paper first presents a new potassium reagent and efficient enrichment agent for direct recovery of potassium from seawater, i. e. , 1, 2, 4, 5-tetrahydroxybenzen -O, O' , O', O'''- tetraacetic acid (TTAH4). The synthetic method of TTAH4, its enrichment behaviour for potassium ion in low concentration solution and seawater, and the chemical structure of its corresponding potassium salt have been investigated. A mechanism which caused the uptake of potassium ion is suggested. Elementary analysis and IR-spectrum determination of the potassium salt proved correct evidence for a polynuclear complex, i. e. , (TTAH3K)n. Thus, the mechanism which caused the uptake of potassium ion may be interpreted in terms of the formation of polynuclear chains as a continual sandwich type coordination complex.
文摘The reaction of perfluoroalkyliodides,perfluoroalkylbromide,1,1, 1-trifluoro-2,2,2-trichloro-ethane,and carbon tetrachloride with thiourea dioxide in aqueous acetonitrile solution gave the corresponding sulfinate in good yield.
