定量核磁共振波谱法测定3种低聚果糖的含量北大核心CSCD

以蔗糖为内标物,氘代水为溶剂,采用氢-1核磁共振波谱法(1H-NMR)测定蔗果七糖、蔗果八糖、蔗果九糖等3种低聚果糖(FOS)的含量。优化后的1H-NMR参数如下:温度25℃,谱宽(2~14)×10^(-6),脉冲角度45°,脉冲延迟时间5 s,采样时间3 s,扫描次数16次。对蔗果七糖、蔗果八糖和蔗果九糖样品进行了仪器精密度和重复性试验,测定值的相对标准偏差(n=6)均小于0.50%。方法用于测定3种样品含量,测定结果与质量平衡法所得结果进行了比较,经F检验法评估,两种方法具有显著性差异。但由于定量核磁共振波谱法作为绝对含量的测定方法,仅需常见的化学品即可直接对待测成分进行测定,可以佐证质量平衡法的赋值结果。     

定量核磁法测定CL-20标准物质中有机杂质的含量

采用定量核磁共振波谱法(qNMR)测定六硝基六氮杂异伍兹烷(CL-20)标准物质中有机杂质的含量。核磁谱图解析证明,主要有机杂质成分为残余溶剂乙酸乙酯和中间体五硝基-乙酰基六氮杂异伍兹烷(MPIW),以不含四甲基硅烷(TMS)的氘代丙酮为溶剂,将六甲基二硅醚的四氯化碳标准溶液加入待测液中作为内标,以其谱峰(δ=0.06)作为内标峰对两种有机杂质进行定量分析。考察了延迟时间和采样次数对准确定量的影响,结果显示为确保定量结果的准确性,延迟时间D_1应不小于20 s,采样次数为32次。采用优化后的实验参数进行纯度分析,测得CL-20标准物质中有机杂质乙酸乙酯和MPIW的质量分数分别为0.03516%和0.156 2%,相对标准偏差(RSD)分别为0.91%和0.86%。     

氯化镁-乙醇络合物中乙醇的NMR定量研究

利用核磁氢谱技术对氯化镁-乙醇络合物中的乙醇进行定量分析研究,结果表明,采样时间和延迟时间的值对定量结果有一定的影响。以四氢呋喃为内标,将采样时间和延迟时间分别设定为4s和20s,利用核磁氢谱内标法测得氯化镁-乙醇络合物中乙醇的质量分数为55.40%,与热重法测定结果相符合。该方法测定结果的相对标准偏差为0.13%(n=6)。     

NMR对MDI在稀溶液中水解反应机理的表征

采用核磁共振波谱(NMR)研究了二苯基甲烷二异氰酸酯(MDI)在稀溶液中的水解反应机理.将同一MDI样品分别溶解在氘代氯仿、氘代丙酮和加入少量水分的氘代二甲基亚砜溶剂(DMSO)中,进行核磁共振氢谱(1H NMR)、核磁共振碳谱(13C NMR)测试.结果显示,MDI在含水的DMSO溶剂中测得的谱图与氘代氯仿、氘代丙酮中的差别显著.对该溶液进行了13C-1H异核近程相关(HMQC)、13C-1H异核远程相关(HMBC)及碳原子级数(DEPT 135)测试,并利用经验公式对其进行了详细归属,确认了反应产物的结构.分析得知MDI在含水溶剂中迅速反应,异氰酸酯基转化为脲基和氨基基团.异氰酸酯与水反应生成氨基基团,其与异氰酸酯反应活性比水高,对位取代氨基与水的竞聚率比值为7.1,邻位为1.4,对位取代氨基活性约是邻位的5倍.     

胺烷基二茂铁衍生物研究(Ⅱ)——(N、N-二乙基)胺甲基二茂铁钯配合物与烯烃的反应

本文报道了(N,N-二乙基)胺甲基二茂铁钯配合物的合成及其与烯烃的反应,以及(N,N-二乙基)胺甲基二茂铁(Ⅰ)、钯配合物(Ⅱ)和反应产物的波谱性质。 1 实验 1.1 仪器 IR光谱用Shimadzu IR-450红外分光光度计测定,固体用KBr压片,液体用CsI涂片。Ⅰ和反应产物的~1H NMR谱用Varian EM-390核磁共振仪测定,氘代氯仿作溶剂;Ⅱ用Varian XL-200核磁共振仪测定;氘代二甲亚砜作溶剂。均以TMS作内标。     

端羟基超支化聚酯分子结构的表征

采用一维~1H-NMR、~(13)C-NMR、无畸变极化转移增强(DEPT)谱、二维核磁异核单量子相干谱(HSQC)和~1H-~(13)C异核远程相关谱(HMBC)等方法,对第2代超支化脂肪族聚酯HB-20的分子结构进行了表征。~1H-NMR和~(13)C-NMR谱图中各出峰得到归属,同时HB-20的分子骨架结构得以明确解析;由~1H-NMR中树枝状、线形和端基甲基(D-CH_3、L-CH_3和T-CH_3)三种结构相对峰面积计算得到HB-20的平均支化度为0.47;由羟值测试和核磁共振结果分别计算得到HB-20的数均分子量为1 878、1 876,两者接近。HB-20的分子结构得到明确的表征。     

反门控去耦技术-定量核磁共振法测定染料木素的含量北大核心CSCD

以香草扁桃酸为内标物,提出了测定染料木素的定量核磁共振法(qNMR).采用反门控去耦模式采集氢谱,驰豫延迟时间为40 s,扫描次数为32次,采集时间为4.0 s,溶剂为氘代二甲亚砜,以染料木素中化学位移(δ,×10^(-6))6.38的峰为定量峰,香草扁桃酸中δ6.96为内标物信号峰.结果表明,染料木素与内标物香草扁桃酸的质量比在0.83~7.50内,与其定量峰和内标物信号峰的峰面积比值呈线性关系,检出限(3.3s/k)为0.2 g􀅰L^(-1).在精密度试验中,测定值的相对标准偏差(n=6)均小于0.35%;稳定性试验显示供试品溶液在避光条件下24 h内稳定.方法用于实际样品的分析,测定结果与国家标准GB/T 23788-2009的一致.     

核磁氢谱法测定葡萄酒中的乙醇

以 3 三甲基甲硅烷基 2 ,2 ,3,3 四氘代丙酸钠 (TSP)为内标物 ,利用核磁氢谱法测定葡萄酒中的乙醇。用核磁氢谱法测得的葡萄酒国际比对样品中乙醇的含量为 (81.11± 0 .2 1)mg/g ,与气相色谱法对葡萄酒中乙醇的定值结果一致。     

~1H核磁共振法测定三氯生的纯度

以丙烯酰胺为内标,氘代二甲基亚砜(DMSO-d6)为溶剂,对用1 H核磁共振法测定三氯生纯度条件进行试验。在脉冲延迟时间20s和扫描次数64等条件下得到1 H-NMR谱图。选择H-11(δ6.88)和δ5.59分别作为样品和内标的定量峰,取其积分峰面积平均值按公式计算三氯生的纯度。结果表明:样品与内标物的质量比在1.01~10.16内,与其定量峰面积比值呈线性关系。平行测定同一样品6份,按所得样品对内标物定量峰面积的比值,计算其相对标准偏差(n=6)为0.12%。按所提出方法分析了三氯生实样,结果的平均值(n=3)为99.78%,与质量平衡法所得结果(99.81%)相符。     

保健食品中壮阳类西药成分的核磁共振氢谱定量分析

建立了保健食品中枸橼酸西地那非、他达拉非、伐地那非的核磁共振氢谱定量(1H q NMR)分析方法。采用布鲁克Avance DRX 500超导核磁共振波谱仪,以氘代二甲亚砜为溶剂,2,3,5-三碘苯甲酸为内标物,优化了仪器采集参数,并进行了方法验证。结果表明:当内标添加量为2 mg、内标与待测化合物摩尔比在1∶0.1~1∶1.2范围时,标准曲线线性良好,相关系数(r2)不小于0.999;枸橼酸西地那非、他达拉非、伐地那非的检出限分别为0.045,0.026,0.033 mg/m L,定量下限分别为0.218,0.128,0.159 mg/m L;日内精密度RSD值分别为0.38%,0.85%,0.34%;日间精密度RSD值分别为0.72%,1.2%,1.4%。利用所建立的方法对13种实际样品进行定量分析;并将测试结果与HPLC-DAD法测试结果进行比较,两种测试结果的RSD在1%~8%之间。     

Synthesis and NMR Spectroscopic Investigation of a Macrocyclic Diphosphine Ligand and its nickel(II) and palladium(II) complexes

The preparation of a macrocyclic diphosphine ligand 5 incorporating a binaphthyl unit and its Ni^II and Pd^II complexes, 6 and 7 , is described. A complete assignment of ¹H,- ¹³C-, and ³¹P-NMR data on the basis of 2D NMR spectroscopy (¹H, ¹H-, ¹³C, ¹H-, ³¹P, ¹H-, ³¹P, ¹³C-COSY) was possible for 5 , and also – in part – for 6 and 7 .     

Facile synthesis, antioxidant and antimicrobial activity of amino methylene bisphosphonates

A green and efficient preparation method for the amino bisphosphonates is accomplished by simple mixing and stirring of diethylphosphite, triethylorthoformate and various amines in the presence of amberlyst-15 as catalyst at room temperature under solvent free conditions. The title compounds are characterized by IR, (1)H-, (13)C-, (31)P-NMR and mass spectra, also studied their antimicrobial and antioxidant activity.     

Synthesis and antimicrobial activity of N-(substituted)-N'-(2,3-dihydro-2-oxido-5-benzoyl-1H-1,3,2-benzodiazaphosphol-2-yl) ureas

N-(substituted)-N'-(2,3-dihydro-5-benzoyl-2-oxido-1H-1,3,2-benzodiazaphosphol-2-yl) ureas were synthesized by reacting 3,4-diaminobenzophenone (4) with different chlorides of carbamidophosphoric acids (3) in the presence of triethylamine at 40-45 degrees C. Their 1H-, 13C- and 31P-NMR spectral data are discussed. The title compounds were screened for antifungal and antibacterial activity against the fungi Aspergillus niger and Fusarium solani and bacteria Escherichia coli and Staphylococcus aureus. These compounds showed higher antibacterial activity when compared with antifungal activity.     

Synthesis, anti-bacterial and anti-oxidant properties of thiadiazaphosphol-2-ones

4-Amino-5-phenyl-4H-1,2,4-triazole-3-thiol (1) underwent facile condensation with various phosphorus dichlorides (2a-j) in the presence of triethylamine in dry tetrahydrofuran at 60-65 degrees C and afforded corresponding thiadiazaphosphol-2-ones (3a-j). Their chemical structures were characterized using IR, (1)H-, (13)C-, (31)P-NMR and Mass spectral studies. All the title compounds were screened for antioxidant properties by radical scavenging methods such as 1,1-diphenyl-2-picryl hydrazyl (DPPH), hydroxyl and lipid peroxidation. They exhibited potent in vitro antioxidant activity dose dependently. Their bioassay showed them to possess significant antibacterial activity.     

Precision 1H-1H distance measurement via 13C NMR signals: utilization of 1H-1H double-quantum dipolar interactions recoupled under magic angle spinning conditions

We applied the POST-C7 DQ-dipolar recoupling pulse sequence to the measurement of (1)H-(1)H distances with high precision. The spectral resolution is enhanced by detecting the (1)H magnetization via (13)C signals. A least-squares fitting of the build-up curve of the transferred magnetization to the exact numerical simulations yielded a (1)H(alpha)-(1)H(beta) distance of 248 +/- 4 pm for fully (13)C-labeled L-valine. This distance agrees with the neutron diffraction study. The negative transferred magnetization clearly indicates that the direct DQ (1)H-(1)H dipolar couplings have the largest effect. The signal for the magnetization transfer builds up rapidly by the direct (1)H-(1)H dipolar coupling, and decreases to zero at longer mixing time when the relayed magnetization transfer becomes significant. This large intensity change of the signal leads to the high precision in the distance measurement. We inspected factors that limit the effective bandwidth of the POST-C7 recoupling for the (1)H and (13)C homonuclear spin systems. The spin interactions at times shorter than the cycle time of the C7 sequence were also evaluated to measure the distances. The carbon-detected 2D (1)H DQ mixing experiment was demonstrated for the measurement of multiple (1)H-(1)H distances.     

Acyl- und Alkylidenphosphane. XVII. Triacetylphosphan aus Tris(trimethylsilyl)phosphan

Acyl- and Alkylidenephosphines. XVII. Triacetylphosphine from Tris(trimethylsilyl)-phosphine Tris(trimethylsilyl)phosphine reacts at 0°C with excess acetyl chloride in cyclopentane to form chlorotrimethylsilane and triacetylphosphine 3a . In contrast to the corresponding 2,2-dimethylpropionyl derivate (Z)- 5b the intermediate compounds (E)- and (Z)-acetyl-[1-(trimethylsiloxy)ethylidene]phosphine 5a are thermally instable. They could not be isolated in a pure state, but were characterized by NMR spectroscopic methods only. The isomers differ scarcely in their chemical shift values, but very much in their coupling constants. If the solution is cooled unsufficiently diacetyl-[1-(trimethylsiloxy)vinyl]phosphine 7 and the keto-enol-tautomers of diacetylphosphine K-/E- 2a are formed to a greater extend. ¹H-{³¹P}-INDOR experiments allowed the correlation between ¹H- and ³¹P-NMR resonances and hence the correct identification of the phosphines formed. Within days the compounds 2a and 7 also react at +20°C with an excess of acyl halide to give triacetylphosphine 3a .     

Living reversible anonic polymerization of N,N-diethylamine-1,3,2-dioxaphosphorinan

Polymerization of the cyclic amide of P^III is described for the first time. The N,N-diethylamine-1,3,2-dioxaphosphorinan was shown to give living reversible polymerization with anionic initiators. Lithium and sodium derivatives were found to be inactive. ¹H-, ¹³C-, and ³¹P-NMR indicated that the polymer strictly reflects the monomer structure and is formed without any isomerization, the polymer chain being $\rlap{--} ({\rm OP}\left( {{\rm NR}_{\rm 2} } \right){\rm O(CH}_{\rm 2} \rlap{--} )_3 )_n $. Initiation involves attack of the anion on the P atom. From the dependence of the equilibrium monomer concentration on temeprature ΔH_1s = 1.5 ± 0.2 kcal·mol^?1 and ΔS_1s = 4.6 ± 0.6 cal·mol^?1·°K^?1.     

[Cu(dien)Cl]+与核苷酸作用的1H、31P NMR研究

本文用~1H-NMR和~(31)P-NMR谱研究了[Cu(dien)Cl]~+与5＇-AMP、5＇-GMP和5＇-CMP在pD=6.00条件下的共价键合作用.氢核磁共振谱研究表明[Cu(dien)]~(2+)与5＇-AMP可以在N-7和N-1位上键合,但N-7是最有利的键合位置.配离子与5＇-GMP、5＇-CMP、分别键合在N-7和N-3位置上.~(31)P核磁共振谱研究结果则表明[Cu(dien)]~(2+)还可以与单核苷酸上的磷酸酯根键合.并根据显著加宽质子峰及~(31)P峰的最低[Cu(dien)Cl]~+浓度,比较了[Cu(dien)]~(2+)对三种核苷酸的碱基与磷酸酯根的亲力.     

Synthesis and application in polypropylene of a novel of phosphorus-containing intumescent flame retardant

A novel phosphorus-containing triazine oligomer poly(2-morpholinyl-4-penta-erythritol phosphate-1,3,5-triazine) (PMPT) was synthesized as a kind of tri-component intumescent flame retardant (IFR). The chemical structure of PMPT was characterized by FTIR, 1H-NMR and 31P-NMR, and the mechanical and flammability properties of FR-PP were measured. The FTIR results showed that the expected chemical reactions had happened at each step. The 1H-NMR and 31P-NMR spectra also agreed with the chemical structure of PMPT. The slight effect of PMPT on the mechanical properties of FR-PP suggested that PMPT and PP are compatible. The high limited oxygen index (LOI) values of FR-PP revealed that PMPT was an efficient IFR and there was the synergistic effect between PMPT and ammonium polyphosphate/ pentaerythritol (APP/PER).     

Use of 13C as an indirect tag in 15N specifically labeled nucleosides. Syntheses of [8-13C-1,7,NH2-15N3]adenosine, -guanosine, and their deoxy analogues

We have previously reported the use of a 13C tag at the C2 of 15N-multilabeled purine nucleosides to distinguish the adjacent-labeled 15N atoms from those in an untagged nucleoside. We now introduce the use of an indirect tag at the C8 of 15N7-labeled purine nucleosides. This tag allows unambiguous differentiation between a pair of 15N7-labeled purines in which only one is 13C8 labeled. Although the very small C8-N7 coupling (<1 Hz) precludes its direct detection in 1D 15N spectra, 2D 1H-15N NMR experiments display the large C8-H8 coupling (>200 Hz) because H8 is coupled to both N7 and C8. The 13C8 atom is introduced by means of a ring closure of the exocyclic amino groups of a pyrimidinone using [13C]sodium ethyl xanthate. Here, we present methods for the syntheses of [8-13C-1,7,NH2-15N3]adenosine, -guanosine, and their deoxy analogues.