Synthesis of polyesters as binders for deinkable inks. V. Structural analysis of the polyesterification between o-phthalic anhydride and trimethylolpropane in bulk at 165°C by high resolution 13C and 1H nuclear magnetic resonance

Structural analysis of the polyesterification in bulk without external catalyst at 165°C between o-phthalic anhydride (P) and trimethylolpropane (1,1, 1-tri(hydroxymethyl)propane) (T) with a mole ratio ([−COOH]/[−OH])=0·70 has been carried out by high resolution ¹³C nuclear magnetic resonance (¹³C NMR) in DMSO-d₆ and CDCl₃ solutions and by ¹H nuclear magnetic resonance (¹H NMR) in CDCl₃ solution. The use of CDCl₃ as NMR solvent has allowed us to identify several signals, which have been assigned to trimethylolpropane monoesters with different esterification degree in the o-phthalate residue. Identically, we have detected signals assignable to chain-end monoesters in structures with different chain lengths. These monoesterified structures have also been confirmed by analysing, by the same procedures, samples modified by diazomethane addition to the samples in chloroformic solution. These modified samples have also been used to determine free acid groups as their methoxylic derivatives by ¹H NMR in CDCl₃ solution. The values compare very well with those obtained by ¹³C and ¹H NMR spectro-scopies in both solvents in some other regions of the spectra. It has been found that NMR allows quantitative determination as a function of the reaction time, of the conversion of acid P and alcohol T functions, as well as monoester and diester of P distributions and those of free, mono- di- and tri-esterified T. We have not observed any detectable signs of gelation. ©1997 SCI     

Stereochemistry of Neolignans - A Revised Structure for a Neolignan Isolated from the Roots of Piper capense

The erythro8-O-4′ neolignan IIIb was synthesized and was found to have identical ¹H and ¹³C NMR characteristics to a neolignan reported as a component of the roots of Nardostachys jatamansi. The NMR spectral characteristics of compound IIIb were also identical with those of a neolignan previously obtained from the roots of Piper capense, for which the unlikely 8-O-3′ structure IVa had been proposed. Two further erythro 8-O-4′ compounds IIIc and IIId were prepared, and their assigned ¹³C NMR signals were consistent with those of IIIb. At this time, there appears to be no evidence for the existence of 8-0-3′ neolignans as plant extracts.     

3-三氟甲基-4-[（4-甲基哌嗪-1-基）甲基]苯胺的核磁共振研究

通过1H-1H COSY、HSQC和HMBC等2D NMR技术对3-三氟甲基-4-[（4-甲基哌嗪-1-基）甲基]苯胺的1H NMR和13C NMR谱进行了全归属,给出了相应的耦合常数。     

苯氧菌胺及其Z-异构体的NMR数据全归属

应用核磁共振技术(1H NMR、13C NMR、1H-1H COSY、HSQC、HMBC)解析了苯氧菌胺及其Z-异构体的化学结构,准确归属了1H NMR和13C NMR信号。     

Stereochemical assignments of the nuclear magnetic resonance spectra of isobornyl acrylate/methacrylonitrile copolymers

Isobornyl acrylate (B)/methacrylonitrile (N) copolymers with different compositions were synthesized by the free‐radical bulk polymerization with azobisisobutyronitrile as the initiator under a nitrogen atmosphere at 70°C. The copolymer compositions were calculated from quantitative ¹³C(¹H)NMR spectra. The reactivity ratios of the comonomers in the B/N copolymers determined from the linear Kelen–Tudos method and nonlinear error‐in‐variable method were r_B = 0.66 ± 0.11 and r_N = 1.54 ± 0.22 and r_B = 0.74 and r_N = 1.65, respectively. The complete spectral assignments of the ¹H‐NMR and ¹³C(¹H)‐NMR spectra were carried out with the help of distortionless enhancement by polarization transfer, two‐dimensional (2D) heteronuclear single quantum coherence, and 2D total correlation spectroscopy. The nitrile carbon of the N unit and the methine and OCH carbons of the B unit were assigned to triad compositional sequences, whereas the β‐methylene carbons of the B and N units were assigned to the tetrad compositional and configurational sequences. The α‐methyl carbon of the N unit was also assigned to the triad level of configurational and compositional sequences. Similarly, the nitrile and quaternary carbon resonances with the methine, methylene, and methyl protons were studied in detail with 2D heteronuclear multiple‐bond correlation spectra. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

A study of the products and mechanism of the thermal oxidative degradation of poly(ethylene oxide) using 1H and 13C 1‐D and 2‐D NMR

The products and mechanism of the thermal oxidative degradation of poly(ethylene oxide) at 150 °C have been analysed using ¹H and ¹³C 1‐D and 2‐D NMR spectroscopy, including COSY, HMQC, HMBC and DOSY techniques. Peaks from methanoate ester chain ends (in the majority), in‐chain esters, peroxy groups, acetal links and ethanoyl chain ends have been assigned. Two small molecule degradation products, 2‐hydroxyethyl methanoate and ethylene glycol dimethanoate have been identified. Copyright © 2004 Society of Chemical Industry     

Synthesis and antibacterial activities of some 2-amino-4-(1,1′-biphenyl-4-yl)-6-aryl-6H-1,3-thiazines

A series of new 2-amino-4-(1,1′-biphenyl-4-yl)-6-aryl-6H-1,3-thiazines has been synthesized, characterized by IR, ¹H NMR, ¹³C NMR, mass and elemental analyses and evaluated for in vitro antibacterial activity against some Gram-positive and Gram-negative bacteria. The antibacterial data revealed that the compounds had better activity against tested organisms than the reference norfloxacin.     

Single-Step analysis of individual conjugated bile acids in human bile using 1H NMR spectroscopy

¹H and ¹³C NMR spectra of intact human bile were assigned using one-dimensional (¹H and ¹³C) and two-dimensional (¹H-¹H and ¹H-¹³C) experiments. Individual conjugated bile acids—glycocholic acid, glycodeoxycholic acid, glycochenodeoxycholic acid, taurocholic acid, taurodeoxycholic acid, and taurochenodeoxycholic acid—were identified. The bile acids were quantified accurately and individually in a single step by using distinct and characteristic amide signals. Making use of ¹³C NMR, the study also suggests a way to analyze unconjugated bile acids separately, if present. Chemical shift assignments and rapid single-step analysis of individual conjugated bile acids from intact bile presented herein may have immense utility in the study of bile acid metabolism and deeper understanding of hepatobiliary diseases.     

Assignment of13C nuclear magnetic resonance signals in fatty compounds with allylic hydroxy groups

¹³C Nuclear magnetic resonance (NMR) signals in several fatty compounds with allylic mono- and dihydroxy groups were assigned by comparing compounds with and without other functional groups (allylic hydroxy, carboxylic acid, respectively, methyl ester at C₁). The simple¹³C NMR spectra of hydroxylated compounds derived from symmetrical alkenes are particularly useful in making assignments. The compounds whose signals were partially assigned are 8-hydroxy-9(E)-octadecenoic acid, 11-hydroxy-9(E)-octadecenoic acid, 8, 11-dihydroxy-9(E)-octadecenoic acid, 9(E)-octadecen-8-ol, and 9(E)-octadecene-8, 11-diol. The present evaluation can be used for assigning signals in other fatty compounds.     

3，9-二（4-甲基苯）-2，4，8，10-四氧杂螺[5．5]十一烷的NMR研究

对含有手性轴的螺环化合物3,9-二（4-甲基苯）-2,4,8,10-四氧杂螺[5．5]十一烷的一维、二维核磁共振谱（^1HNMR,^13CNMR,DEPT,2D^1H—^1HCOSY,HSQC,HMBC）进行了解析和报道。认真的分析了两个六元杂环上四个亚甲基出现的信号,对其所有的NMR谱信号进行了全归属,为研究含杂原子的手性螺环化合物提供了参考数据。     

Simplification and assignment of proton and two-dimensional hetero-correlated NMR spectra of petroleum fractions using gradient selected editing pulse sequences

In this paper, gradient selected (gs) NMR experiments are presented for editing the proton, and two-dimensional (2D) ¹H-¹³C-correlation spectra of different fractions of the petroleum according to the carbon multiplicity. The state of the art experiments allow the much sought after simplification and resolution of the proton, and 2D ¹H-¹³C correlated NMR spectra of such fractions in considerably reduced acquisition times. The proton-edited experiments offer a new and much convenient way of unambiguous estimation of cut-off points between signals from α-methyl and α-methylene protons in ¹H NMR spectra of petroleum fractions. The gs edited 2D ¹H-¹³C correlated spectra of the fractions provide carbon multiplicity information and hetero-nuclear correlation with improved sensitivity in a single experiment leading to complete spectral assignment. These experiments have been applied to complex petroleum fractions for the first time, and show lot of potential to resolve various hitherto unanswered issues concerning the interpretation of the complex NMR spectra of the petroleum products.     

Segmental mobility in poly(isoprene) rubber studied by deuterium-carbon NMR correlation spectroscopy

Summary A HMQC based deuterium-carbon correlation method is used for the first time to study the segmental mobility in a fully deuterated poly(isoprene) (PI) rubber network. The isotropic J _CD couplings can be utilized for polarization transfer between ²H and ¹³C spins in a mobile solid polymer. This makes it possible to correlate the ²H resonances with the ¹³C chemical shifts of the attached carbon in a two-dimensional (2D) experiment, and thus allow the extraction of the individual ²H signals. The experimental data obtained from the 2D correlation spectrum indicates differences in the segmental mobility of the C-D vectors in perdeuterated PI. The conclusions are fully consistent with ²H and ¹³C T ₁ relaxation data. The results shown in this paper demonstrate the potential of ²H-¹³C NMR correlation spectroscopy in solid systems which produce overlapped 1D ²H spectra. Received: 11 December 2000/Revised version: 1 March 2001/Accepted: 1 March 2001     

一种新型有机溴类杀菌剂的结构鉴定

利用微量有机元素分析仪、红外光谱仪、核磁共振波谱仪鉴定了一种从杀菌防霉剂中分离出来的新型有机溴类杀菌剂,并且应用1D和2D核磁共振技术包含1H、13C、DEPT、1H—1HCOSY、HSQC、HMBC 6种NMR分析测试方法,对该杀菌剂的结构进行了确定,对其1H、13C信号进行了归属。     

四苄基二苯甲酰基六氮杂异伍兹烷的结构归属

利用^1H和^13CNMR(包括DEPT）及2D NMR（HMQC,HMBC,NOESY）技术确定了2,4,8,10-四苄基-6,12-二苯甲酰基-2,4,6,8,10,12-六氮杂四环[5.5.0.0^5.9.0^3.11]十二烷的结构。对其^1H和^13CNMR谱进行了全归属,并观察到一些有意义的远程^13C-^1H和^1H-^1H耦合。     

Quantitative valuation of composition in vinylformal,vinylacetate and vinylalcohol ter-copolymers by1H- and13C-n.m.r. spectroscopy

The¹³C-n.m.r. signals were assigned to the composing structural groups of the copolymers. The composition of the copolymers was determined by¹³C n.m.r. using the NOE extinction technique. The analyzed samples were synthesized under normal and relatively mild reaction conditions. Despite this and purification methods that avoided elevated temperatures, it was not possible to find hemiformal groups in any amount. Therefore it is possible to analyze these copolymers composed of formal, vinylacetate and vinylalcohol structural groups in a relatively easy way by means¹H n.m.r.     

Characterization of epoxidized natural rubber by 2D NMR spectroscopy

Assignment of signals in aliphatic region of ¹H NMR spectrum for epoxidized natural rubber was carried out through NMR spectroscopy. The epoxidized natural rubber was prepared by epoxidation of purified natural rubber with peracetic acid in latex stage followed by degradation with propanal and ammonium persulfate. The resulting liquid epoxidized natural rubber was characterized through 1D- and 2D-NMR spectroscopy. The unknown signals in the aliphatic region of the ¹H NMR spectrum were assigned through ¹³C NMR and two-dimensional heteronuclear shift correlation (HETCOR) measurement. The assignments were proved by two-dimensional inverse detected heteronuclear long-range shift correlation (HMBC) and two-dimensional homonuclear shift correlation (COSY) measurements, and they were supported with epoxidized squalene as a model compound through NMR spectroscopy.     

依卡倍特钠的核磁共振数据解析

依卡倍特钠是日本田边公司生产的一种具有覆盖作用的抗胃炎、胃溃疡的新型药物。笔者对依卡倍特钠进行了1H NMR、13C NMR检测,并通过DEPT、gCOSY、gHMQC、gHMBC等2DNMR技术对其NMR数据进行较为详细的解析和NMR信号全归属,为今后的分析鉴定工作提供完善的NMR数据。     

Two-dimensional 1H-, 13C- and 15N-NMR Spectra of Azo Dyes Derived from J-Acid,H-Acid and Gamma Acid

The ¹H-, ¹³C- and ¹⁵N-NMR spectra of compounds prepared by coupling benzenediazonium chloride with J-acid, H-acid and Gamma acid under alkaline conditions have been measured. Two-dimensional H,H-COSY, NOESY, H,C-COSY and COLOC spectra and one-dimensional selective INEPT have been used in the assignment of the ¹H- and ¹³C-NMR signals. The results show that the above-mentioned aminohydroxynaphthalene-sulfonic acids undergo diazo coupling of benzenediazonium chloride ortho to the hydroxyl groups under alkaline conditions. Using δ(¹³C), δ(¹⁵N) and ¹J(¹⁵NH) it has been found that the coupling products exist, in hexadeuteriodimethyl sulfoxide solutions, as equilibrium mixtures of the azo and hydrazone tautomers with strongly prevailing naphthoquinone phenyl-hydrazone configurations.     

Characterization of poly(1‐methyl‐1,4‐butanediol‐1,4‐diyl/2,3,4‐trihydro‐5‐methylfuran‐2,5‐diyl) prepared from natural rubber through 2D NMR spectroscopy

Poly(1‐methyl‐1,4‐butanediol‐1,4‐diyl/2,3,4‐trihydro‐5‐methylfuran‐2,5‐diyl) was prepared by epoxidation of deproteinized natural rubber with m‐chloroperbenzoic acid followed by hydrolysis with sulfuric acid. Characterization of the resulting product was performed through FT‐IR, ¹H NMR, and ¹³C NMR spectroscopies. All signals appearing in the ¹H and ¹³C NMR spectra were assigned by distortionless enhancement by polarization transfer (DEPT), quaternary carbon observation (QUAT), correlation spectroscopy (COSY), and heteronuclear multiple quantum correlation (HMQC) measurements. After proving the primary structure of the product, one pot synthesis of poly(1‐methyl‐1,4‐butanediol‐1,4‐diyl/2,3,4‐trihydro‐5‐methylfuran‐2,5‐diyl) from deproteinized natural rubber latex was carried out with peracetic acid and 2‐propanol. The resulting product was characterized by ¹H NMR spectroscopy on the basis of the assignments established in this study, and its gas permeability was measured for a practical application as a film. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.     

Two-dimensional 1H- and 13C-NMR and 15N-NMR spectra of three azo dyes derived from J-acid and 4-nitroaniline

The ¹H-,¹³C- and ¹⁵N-NMR spectra of three azo dyes prepared by coupling 4-nitrobenzenediazonium chloride with J-acid under both alkaline and acidic conditions have been measured. Two-dimensional H, H-COSY; NOESY; H, C-COSY and one-dimensional selective INEPT have been used in the assignment of the ¹H- and ¹³C-NMR signals. Using δ(¹³C), δ(¹⁵N) and ¹J(¹⁵N¹⁵N) it has been found that the coupling products ortho and para to the hydroxyl group exist, in hexadeuteriodimethyl sulfoxide solutions, as equilibrium mixtures of the azo and hydrazone tautomers with strongly prevailing naphthaquinone phenylhydrazone configurations, whilst the coupling product ortho to the amino group exists almost exclusively as the azo compound.