Several cyclic amino acids (1-4) were synthesized from glycine. Isocyanate ester was prepared as the key intermediate and reacted with dibromoalkanes to afford the target compounds.
Chiral amino cyclic phosphoric acids, 5-amino-2-hydroxy-4-(4-nitrophenyl)-1,3,2-dioxaphosphorinane 2-oxide and 2-hydroxy-4-(4-methylsulfonylphenyl)-5-phthalimido-1,3,2-dioxaphos phorinane 2-oxide are synthesized in go...Chiral amino cyclic phosphoric acids, 5-amino-2-hydroxy-4-(4-nitrophenyl)-1,3,2-dioxaphosphorinane 2-oxide and 2-hydroxy-4-(4-methylsulfonylphenyl)-5-phthalimido-1,3,2-dioxaphos phorinane 2-oxide are synthesized in good over yields (64.2%and 72.8%respectively) from 2-amino-1-aryl-1,3-propanediols. The different reaction conditions are necessary in hydrolysis reactions of amino cyclic phosphonyl chlorides.展开更多
This paper reports the determination of stability constants for complexes of Pb(Ⅱ) with Gly, Ala, Asp and Gly-Gly using both micro-pH-metric titrations and the application of convolution-de- convolution cyclic voltam...This paper reports the determination of stability constants for complexes of Pb(Ⅱ) with Gly, Ala, Asp and Gly-Gly using both micro-pH-metric titrations and the application of convolution-de- convolution cyclic voltammetry at 25℃ and I = 0.10 mol.dm^(-3)(KNO_3). Stability constants were calculated from pH-metric data using the SUPERQUAD computer program and cyclic voltammograms were collected, stored and manipulated using the E G and G CONDECON 300 software. A consider- ably larger ligand: metal ratio (e.g. 50:1) was possible using voltammetry. Under these conditions, hydroxy complex formation was minimised and the formation of bis-complexes optimised. Computer based calculations were carried out on PC-compatible microcomputers fitted with mathematics co- processors. Evaluation of results from the two techniques suggests that stability constants for the species [PbL_2] are reliable when calculated from voltammetry while those for [PbL] are mote reliable when determined by pH-metric titration.展开更多
基金the National Natural Science Foundation of China(No.20272001)
文摘Several cyclic amino acids (1-4) were synthesized from glycine. Isocyanate ester was prepared as the key intermediate and reacted with dibromoalkanes to afford the target compounds.
基金Supported by the Science and Technology Fund of Wuhan City(No:996001016G)
文摘Chiral amino cyclic phosphoric acids, 5-amino-2-hydroxy-4-(4-nitrophenyl)-1,3,2-dioxaphosphorinane 2-oxide and 2-hydroxy-4-(4-methylsulfonylphenyl)-5-phthalimido-1,3,2-dioxaphos phorinane 2-oxide are synthesized in good over yields (64.2%and 72.8%respectively) from 2-amino-1-aryl-1,3-propanediols. The different reaction conditions are necessary in hydrolysis reactions of amino cyclic phosphonyl chlorides.
文摘目的探究绿原酸(chlorogenic acid,CGA)氧化形成的CGA醌与氨基酸侧链基团在不同pH条件下的反应效率,为CGA与蛋白质共价互作反应位点的调控提供理论依据。方法利用循环伏安法研究了酸性(pH 5.0)、中性(pH 7.0)和碱性(pH 8.0)条件下CGA与氨基酸侧链基团的反应效率,采用超高效液相色谱-四极杆飞行时间串联质谱法(ultra performance liquid chromatography-quadrupole time of flight-tandem mass spectrometry,UPLC-QTOF-MS/MS)对反应产物进行结构鉴定。结果在pH7.0、扫描速率10mV/s,0.20mmol/LCGA与10.00mmol/L封闭α-氨基的氨基酸的反应效率依次为Nα-乙酰-L-半胱氨酸(~100.00%)≈Nα-乙酰-L-色氨酸(~100.00%)>Nα-乙酰-L-酪氨酸(39.20%±2.19%)>Nα-乙酰-L-赖氨酸(10.25%±0.83%)>Nα-boc-L-组氨酸(~0.00%)≈Nα-乙酰-L-精氨酸(~0.00%);在其他反应条件相同的情况下,缩小扫描电压范围至-0.4~0.4V,CGA与Nα-乙酰-L-半胱氨酸、Nα-乙酰-L-色氨酸及Nα-乙酰-L-酪氨酸的共价互作效率分别为~100%、12.83%±1.16%及~0%;pH 7.0或8.0时,GCA与氨基酸残基的共价互作效率高于pH 5.0;CGA醌与Nα-乙酰-L-赖氨酸、Nα-乙酰-L-精氨酸的反应产物以氧化态的醌-氨基酸形式存在,而CGA醌与Nα-乙酰-L-半胱氨酸、Nα-boc-L-组氨酸、Nα-乙酰-L-色氨酸的反应产物以还原态的酚-氨基酸形式存在。结论CGA氧化形成的CGA醌可与蛋白质中半胱氨酸、色氨酸、赖氨酸、组氨酸及精氨酸残基发生反应,其中半胱氨酸残基是CGA醌与蛋白质共价互作的主要位点,可通过调整食品体系的pH和绿原酸醌浓度实现绿原酸-蛋白质共价互作位点的调控。
文摘This paper reports the determination of stability constants for complexes of Pb(Ⅱ) with Gly, Ala, Asp and Gly-Gly using both micro-pH-metric titrations and the application of convolution-de- convolution cyclic voltammetry at 25℃ and I = 0.10 mol.dm^(-3)(KNO_3). Stability constants were calculated from pH-metric data using the SUPERQUAD computer program and cyclic voltammograms were collected, stored and manipulated using the E G and G CONDECON 300 software. A consider- ably larger ligand: metal ratio (e.g. 50:1) was possible using voltammetry. Under these conditions, hydroxy complex formation was minimised and the formation of bis-complexes optimised. Computer based calculations were carried out on PC-compatible microcomputers fitted with mathematics co- processors. Evaluation of results from the two techniques suggests that stability constants for the species [PbL_2] are reliable when calculated from voltammetry while those for [PbL] are mote reliable when determined by pH-metric titration.
