13C NMR and 2D (H,H and H,C COSY) Spectra of Triazolo-triazino-indole Derivatives and the Conformational Analysis of the Respective C-Nucleoside Analogues

¹³C NMR and 2D (H,H and H,C COSY) spectra of selected examples of sugar (5H-1,2,4-triazino[5,6-b]-indol-3-yl) hydrazones, peracetylated sugar-1-acetyl -1- (5-acetyl-1,2,4-triazino[5,6-b]indol-3-yl)hydrazones, and 10-acetyl-3-(per-0-acetylalditol-1-yl)-1,2,4-triazolo[4′, 3′:2,3][1,2,4]triazino[5,6-b]indole have been reported. The conformation of the latter C-nucleoside analogues have been determined by analysis of their ¹H NMR spectra. The D-galacto, D-manno and L-arabino isomers are preponderantly existing in the planar zigzag arrangement of carbon atoms.     

Structure Elucidation and Assignment of 1H and 13C Spectra of the New Fused Cyclobutane-Naphthofuran Derivative by Two-Dimensional NMR in Different Solvents

One of the major product from the photodimerization of 2-[2-(2-methyl-phenyl)ethenyl)]naphtho[2. 1-b]furan (1) is a new fused cyclobutane-naphthofuran derivative, 6-(2-methylphenyl)-1-[2-(2-methylphenyl)ethenyl]-7-(2-naphtho-[2,1-b]furyl)-3-[2,1]naphtho-2-oxabicyclo[3.2.0]hept-3-ene (2). Its ¹H and ¹³C NMR spectra were fully assigned by the application of COSY, LR COSY, NOESY, APT and HETCOR experiments in deuterated chloroform, acetone and benzene solutions.     

Spectral Characteristics of the Reaction Products of 5-Phenyl-2,3,4-furantrione with o-Diamines

The ¹H and ¹³C NMR and mass spectra of 2-(2-amino-4,5-dimethylphenylcarbamoyl)-3-(hydroxyphenylmethyl)-6,7-dimethylqinoxaline (2), 3-(hydroxyphenylmethyl)-6,7-dimethylquinoxalin-2-carboxylic-γ-lactone (5), 3-(hydroxyphenylmethyl)-6,7-dimethylquinoxalin-2-carboxylic acid phenylhydrazide (6), 3-[2-hydroxy-2-phenyl-1-(phenylhydrazono)ethyl]-6,7-dimethyl-2(1H)-quinoxalinone (7), 2,3-dihydro-6,7-dimethyl-3-phenylhydrazono-2-phenylfuro[2,3-b]auinoxaline (8), 3-(hydroxyphenylmethyl)-6,7-dimethyl-1-phenylflavazole (9), and 3-(acetoxyphenylmethyl)-6,7-dimethyl-1-phenylflavazole (10) have been studied.     

TOTAL ASSIGNMENT OF 1H AND 13C NMR SPECTRA OF A BRIDGED TRIRUTHENIUM CLUSTER-POLYPYRIDINE DIMER BASED ON 2D (COSY,HMQC, AND HMBC) TECHNIQUES

The bridged ruthenium cluster-polypyridine dimer [Ru₃O(CH₃COO)₆(py)₂(tmbpy)Ru(bpy)₂(Cl)](PF₆)₂ (py = pyridine, = 2, 2′-bipyridine and tmbpy = 4, 4′-trimethylenedipyridine) has been synthesized and structurally characterized based on ¹H and ¹³C NMR spectroscopy. This species exhibits a complex pattern of NMR signals due to the presence of a paramagnetic [Ru₃O] core and seven non-equivalent aromatic rings. 2D NMR (COSY, HMQC and HMBC) correlation techniques have been required for the total assignment of the ¹H and ¹³C NMR spectra.     

1H and 13C NMR Determination of the Enantiomeric Purity of Substituted 4-Amino-3- (thien-2-Yl)-Butyric Acids and 4-Amino-3-(Benzo[b]Furan-2-yl)-Butyric Acids,Ligands of the GabaB Receptor.

The enantiomeric composition and absolute configuration of 4-Amino-3-(benzo[b]furan-2-yl)-Butanoic Acids and of 4-Amino-3-(thien-2-yl)-Butanoic Acids 1 may be accurately determined by ¹H and ¹³C nuclear magnetic resonance analysis of the corresponding derivatives 3 prepared by reaction with chiral reagents. Correlation with HPLC is signaled.     

2-(2-苯并噁唑啉酮-3-甲基)-6-芳基-咪唑[2,1-b][1,3,4]噻二唑的NMR谱研究

许多文献已报道,含有咪唑[2,1-b][1,3,4]噻唑环的衍生物具有抗癌、抗结核、抗菌、抗真菌、抗惊厥、止痛等活性. 该文合成了一个新的在医药方面具有潜在应用价值的咪唑[2,1-b][1,3,4]噻二唑衍生物,即2-(2-苯噁唑啉酮-3-甲基)-6-苯基-咪唑[2,1-b][1,3,4]噻二唑,并利用2D NMR技术对其¹H NMR 和¹³C NMR谱进行了全归属.      

Analysis of 1H and 13C{1H} NMR Spectral Parameters and Geometries of Three Isomeric Diphenylbicyclo[2.2.1]Hept-5-Ene-2,3-Dicarboxylic Anhydrides

Diels-Alder adducts of 1,4-diphenyl-1,3-cyclopentadiene and maleic anhydride were investigated by recording the ¹H and ¹³C{¹H} NMR spectra of three isomeric diphenylbicyclo[2.2.1]hept-5-ene endo and exo 2,3-dianhydrides. the spectra were recorded in CD₂Cl₂ and analysed completely. the effect of the endo and exo configuration of the anhydride ring on the chemical shifts of the bridgehead phenyl protons is discussed. the ortho protons of the exo isomers resonate at higher field than those of the endo isomer, and the resonance pattern of the aromatic protons is narrower in the exo than the endo anhydride. the aromatic regions of the spectra are compared with the same regions of the ¹H NMR spectra of the earlier investigated addition products of 1,4-di-p-tolyl-1,3-cyclopentadiene and 1-phenyl-4-p-tolyl-1,3-cyclopentadiene with maleic anhydride. Chemical shifts of the bridge protons are explained on the basis of X-ray data of the compounds and MacroModel calculations on the minimum energy conformations.     

13C NMR Chemical Shifts of Heterocycles: Empirical Substituent Effects in 5-Halomethylisoxazoles

Evaluation by empirically derived equations for the Substituent effect (α, β, γ, δ) on the ¹³C NMR chemical shifts for C-3, C-4. C-5 and halomethyl-substituent carbon (C-6) in isoxazoles 1-5 [where C-3 substituent (R¹) = H, alkyl or phenyl, C-4 Substituent (R²) = H, alkyl, and C-5 substituent (R³) = di-or trihalomethyl, methyl and H], taking as reference the compound la, is reported. From the calculated values for the α, β, γ, δ effects for each substituent it was possible to estimate the chemical shift of each carbon of the compounds 1–5. The ¹³ C chemical shifts of the C-3, C-4, C-5, C-6 of these compounds, can be estimated with good precision: 94% of the calculated chemical shifts are found to be within ±1.0ppm, and 100% are found to be within ±1.5ppm.     

Structural Assignment of Isomeric S‐ and S,N‐1‐Alkoxycarbonylalkylated 6‐Amino‐2‐thiouracil Derivatives by Means of 1H and 13C NMR Spectroscopy

Abstract

The structures of new isomeric 2‐alkoxycarbonylalkylthio‐ and 2‐alkoxy‐ carbonylalkylthio‐1‐alkoxycarbonylalkyl‐6‐aminouracils (1–21) have been established on the basis of the ¹H NMR and ¹³C NMR spectroscopic data. The ¹H NMR and ¹³C NMR spectra of 1–21 have been fully assigned by a combination of two‐dimensional experiments [heteronuclear multiple quantum coherence (HMQC) and heteronuclear multiple bond correlation (HMBC)]. The ¹³C NMR spectra have been shown to be able to differentiate between isomers.     

1H NMR Studies on the Methylation,Protonation, and Hydration Sites in Some Benzo[b]Naphthyridines (Azaacridines)

Abstract

The 300.13 MHz ¹H NMR spectra of the methylated and protonated 6(9)-methylbenzo[b][1,x] naphthyridines (x=5, 6, 7, 8) (5-methylazaacridines) were collected at 298 K in deuterated dimethyl sulfoxide and chloroform, respectively. The methylation and protonation sites were assigned by comparisons of these data with those of the free bases. The results were compared with similar data for related heterocycles and showed that both methylation and protonation occur at the nitrogen in the outer pyrido ring in all four series.

The hydration site in some 2-and 3-azaacridines was determined by specific line broadening in their ¹H NMR spectra to be the same nitrogen as that involved in methylation and protonation. Variable temperature ¹H NMR demonstrated that the specific line broadening results from some changes of ¹⁴N quadrupolar relaxation produced by the slow chemical exchange between unhydrated and hydrated species. Deuterium exchange experiments indicated that the direct spin-spin interaction of a water proton and the protons alpha to the hydrated nitrogen may also have some contribution.     

Acyclic Analogues of Purine Nucleosedes: One- and Two-Dimensional 1H and 13C NMR Evidences for N-9 and N-7 Regioisomers

It has been established by means of one-and two-dimensional ¹H and ¹³C NMR Spectroscopy that adenine acyclonucleosides are substituted at either N-9 or N-7 with 2',3'-dihydroxyprop-1-yl (2 and 3) or 2'-hydroxyprop-1-yl (4 and 5) aliphatic chains. The N-3 isomer has not been formed, as claimed previously. This was deduced on the basis of chemical shifts, substituent induced chemical shifts, magnitude and multiplicity of C-H couplings as well as connectivities in 2D homo-and heteronuclear correlation spectra.     

The 2D {P} Spin-Echo-Difference Constant-Time [C, H]-HMQC Experiment for Simultaneous Determination of JH3′P and JC4′P in C-Labeled Nucleic Acids and Their Protein Complexes

A two-dimensional {³¹P} spin-echo-difference constant-time [¹³C, ¹H]-HMQC experiment (2D {³¹P}-sedct-[¹³C, ¹H]-HMQC) is introduced for measurements of ³J_C4′P and ³J_H3′P scalar couplings in large ¹³C-labeled nucleic acids and in DNA–protein complexes. This experiment makes use of the fact that ¹H–¹³C multiple-quantum coherences in macromolecules relax more slowly than the corresponding ¹³C single-quantum coherences. ³J_C4′P and ³J_H3′P are related via Karplus-type functions with the phosphodiester torsion angles β and ε, respectively, and their experimental assessment therefore contributes to further improved quality of NMR solution structures. Data are presented for a uniformly ¹³C, ¹⁵N-labeled 14-base-pair DNA duplex, both free in solution and in a 17-kDa protein–DNA complex.     

NMR Studies of Hindered Rotation. The Diels-Alder Adduct of 4-Methyl-1, 2, 4-triazoline-3, 5-dione with Phencyclone: Restricted Motion of Unsubstituted Bridgehead Phenyls.

4-Methyl-1, 2, 4-triazoline-3, 5-dione was produced by lead tetraacetate oxidation of 4-methylurazole and allowed to react with phencyclone, 1-The resulting Diels-Alder adduct, 2, has been characterized by one-and two-dimensional ¹H and ¹³C NMR at 300 and 75 MHz, respectively, at ambient temperatures in different solvents. The NMR data are consistent with hindered rotation of the bridgehead unsubstituted phenyl groups about the C(sp²)-C(sp³) bonds, based on numbers of absorption signals in the ¹H and ¹³C NMR aryl region, together with magnetic anisotropic effects in the ¹H spectrum. The spectral simplicity suggests further that stereochemistry at the ring junction nitrogens involves only a single isomer or very rapidly interconverting “exo”/“endo” isomers (if the ring junction nitrogens are pyramidalized).     

Structural Elucidation of Novel Derivatives of Pyranobisquinolines 1H-NMR, 13C-NMR and Mass Spectroscopic Study of (7H)-6,8-Dichloro-7-methyl-pyrano(3,2-c:5,6-c′)bisquinoline and (7H)-6,8-dichloro-7-methyl-pyrano (3,2-c:5,6-b′)bisquinoline

Elucidation of the structure of hitherto unknown novel pyranobisquinoline derivatives, (7H)-6,8-Dichloro-7-methyl -pyrano(3,2-c;5,6-c′)bisquinoline 5 and (7H)-6,8-Dichloro-7-methyl-pyrano(3,2-c:5,6-b′)bisquinoline 4 obtained as unexpected products¹ in the Michael type reaction of vinylacetate on 4-hydroxyquinoline-2(lH)-one 1 by NMR methods is reported.     

Assignment of the 1H and 13C NMR Chemical Shifts of (3,4-Dihydro-2H-pyran-5-yl)-oxo-acetic Acid Methyl Ester Using the Two Dimensional HMBC Technique

The identification of (3, 4-dihydro-2H-pyran-5-yl)-oxo-acetic acid methyl ester has been realized by combination of two dimensional HETCOR and HMBC techniques. ¹³C and ¹H chemical shifts asignements are described.     

NQR, NMR and Crystal Structure Studies of [C(NH2)3]2HgX4 (X = Br, I)

The crystal structure of [C(NH₂)₃]₂HgBr₄ has been determined at room temperature: monoclinic, space group C2/c, with a = 10.035(2), b = 11.164(2), c = 13.358(3) Å, β = 111.67(3)°, and Z = 4. The crystal consists of planar [C(NH₂)₃]⁺ and distorted tetrahedral [HgBr₄]^2? ions. The Hg atom is located on a two-fold axis such that two sets of inequivalent Br atoms exist in an [HgBr₄]^2? ion. In accordance with the crystal structure, two ⁸¹Br NQR lines widely separated in frequency were observed between 77 and ca. 380 K. [C(NH₂)₃]₂HgI₄ yielded four ¹²⁷I NQR lines ascribable to m = ±1/2 ? ±3/2 transitions, indicating that its crystal structure is different from the bromide complex. The ¹H NMR T ₁ measurements showed a single minimum for the bromide but two minima for the iodide. The analyses based on the C₃ reorientations of the planar [C(NH₂)₃]⁺ ions gave the activation energies of 29.8 kJ mol^?1 for the bromide, and 30.2 and 40.0 kJ mol^?1 for the iodide.     

1H and 13C NMR Determination of 1-Naphtyl-Polymethoxylated Diphenylwiethanes

The complete structural analysis of 1-[(4-methoxyphenyl)-(3,4,5-trimethoxyphe- nyl)methyl]naphtalene 5a and 1-[(2,5-dimethoxyphenyl)-(3,4,5-trimethoxyphenyl) methyljnaphtalene 5b, prepared by alkylation of 1-[chloro-(3,4,5-trimethoxyphenyl) methyl]naphtalene without by-products such as benzofluorene 2, may be accurately determined by ¹H, ¹³C NMR and 2D NMR analysis.     

1H and 13C n.m.r. Conformational Analysis of Adrenergic Drugs. Part 2. N-Isopropyl-N- {3-[4(4-Methoxybenzoylamino)Phenoxy]-2-Hydroxypropyl} Ammonium Chloride,a New β1-Blocking Agent

Abstract

Dynamic and structural features of N-Isopropyl-N- {3-[4(4-Methoxybenzoylamino)Phenoxy]-2-Hydroxypropyl} Ammonium Chloride in [²H₆]DMSO were investigated by measuring ¹³C and ¹H spin-lattice relaxation rates and ¹³C- {¹H} and ¹H- {¹H} n.O.e. Correlation times for main and internal reorientational motions were interpreted in terms of internal rotation around the two planal axes. Selective and double-selective ¹H spin-lattice relaxation rates were measured, wherefrom relevant proton-proton intramolecular distances were calculated. It was shown that the β₁? blocking agent assumes a preferred conformation where extensive intramolecular H-bonding prevents segmental motion along the quaternary ammonium sidechain.     

瓜环与喹啉及其衍生物的相互作用

利用荧光光谱分析方法考察六、七及八元瓜环与喹啉、异喹啉、7-甲基喹啉相互作用的结构特征以及光学特性。与核磁共振技术比较,荧光光谱分析方法具有高灵敏性的特点,不仅可观察到喹啉及其衍生物与七元瓜环相互作用而引起的荧光性质变化;还能观察到它们与六元瓜环或八元瓜环相互作用所产生的变化,这是通常的NMR方法所不能实现的。实验表明喹啉、异喹啉、7-甲基喹啉与六、七及八元瓜环有包结作用,形成多种不同包结比的稳定包结配合物。实验也证实,瓜环与客体之间相互作用受到3种效应的协同影响:(1)疏水性的笼体效应(瓜环以其特殊的疏水性笼状结构,可与多种有机物发生疏水性的笼体作用);(2)亲水性的端口效应(瓜环端口环绕的羰基氧通过离子-偶极相互作用来键合金属离子或有机分子的带电部分);(3)相互作用的客体分子或瓜环笼体空间大小,即尺寸效应。     

2,3-二羟基萘钼多酸有机衍生物的合成及1H NMR和IR谱学研究

本文对二种新合成的2，3－二羟基萘二钼和四钼多酸有机衍生物[n-Bu)4N]2[Mo2O5(OC10H6O)2](Ⅰ）和[n-Bu)4N]2[Mo4O10(OC10H6O)2(OCH3)2](Ⅱ)进行了红外光谱与核磁共振波谱研究，发现[Mo2O5]^2 中钼氧多桥键的红外振动频率较[Mo4O10(OCH3)2]^2 中钼氧多桥键的红外振动频率红移，而在配合物Ⅱ中2，3－二羟基中芳环的^1H化学位移较配合物Ⅰ中向低场移动。同时还发现含二钼配位中心[Mo2O5]^2 的[Mo2O5(OC10H6O)2]^2-与含四钼配位中心[Mo4O10(OCH3)2]^2 的[Mo4O10(OC10H6O)2(OCH3)2]^2-生成条件的差异仅仅只在反应体系的pH值的微小变化，说明钼多酸有机衍生物阴离子是对体系酸碱度极为敏感的物质。