1H‐, 13C‐, and 15N‐NMR chemical shifts for selected glucosides and ribosides of aromatic cytokinins

The ¹H and ¹³C NMR resonances of 16 purine glucosides were assigned by a combination of one‐ and two‐dimensional NMR experiments, including gs‐COSY, gs‐HSQC, and gs‐HMBC, in order to characterize the effect of substituent and the position of glucose unit on the NMR chemical shifts. In addition, ¹⁵N NMR chemical shifts for selected derivatives were investigated by using ¹H? ¹⁵N chemical shift correlation techniques. To map the influence of sugar moiety on the directly bonded nitrogen atom, selected N⁹‐glucosides and their ribose analogs were compared. Characteristic long‐range ¹H? ¹⁵N coupling constants, measured by using ¹H? ¹⁵N gradient‐selected single‐quantum multiple bond correlation (GSQMBC), are also reported and discussed. All compounds investigated here belong to cytokinins, an important group of plant hormones. Copyright © 2010 John Wiley & Sons, Ltd.     

1H‐ und 13C‐NMR‐Spektroskopie

The present state of the routine 1D ¹H‐ and ¹³C‐NMR spectroscopy is reported. After a short introduction into the basic theory the current spectrometer and software systems are discussed. Using an example from natural product chemistry the procedures during the analysis of the NMR spectra are explained.     

Complete assignment of 1H and 13C NMR spectra of α‐phenylsulfinyl‐N‐methoxy‐ N‐methylpropionamide and some p‐substituted derivatives

The complete assignment of the ¹H and ¹³C NMR spectra of the diastereomeric pairs of some α‐arylsulfinyl‐substituted N‐methoxy‐N‐methylpropionamides with the substituents methoxy, methyl, chloro, nitro is reported. Copyright © 2008 John Wiley & Sons, Ltd.     

1H, 13C and 15N NMR assignments for N‐ and O‐acylethanolamines,important family of naturally occurring bioactive lipid mediators

The complete ¹H, ¹³C and ¹⁵N NMR signal assignments of some N‐ and O‐acylethanolamines, important family of naturally occurring bioactive lipid mediators, were achieved using one‐dimensional and two‐dimensional experiments (gs‐HMQC and gs‐HMBC). Copyright © 2012 John Wiley & Sons, Ltd.     

Characterization of 4,5‐Dihydro‐1H‐Pyrazole Derivatives by 13C NMR Spectroscopy

The ¹³ C NMR resonances of 19 1‐acyl‐3‐(2‐nitro‐5‐substitutedphenyl)‐4,5‐dihydro‐1H‐pyrazoles, and 19 1‐acyl‐3‐(2‐amino‐5‐substituted)‐4,5‐dihydro‐1H‐pyrazoles, were completely assigned using the concerted application of one‐ and two‐dimensional NMR experiments (DEPT, gs‐HSQC and gs‐HMBC). Copyright © 2012 John Wiley & Sons, Ltd.     

Complete assignment of NMR data of 22 phenyl‐1H‐pyrazoles' derivatives

Complete assignment of ¹H and ¹³C NMR chemical shifts and J(¹H/¹H and ¹H/¹⁹F) coupling constants for 22 1‐phenyl‐1H‐pyrazoles' derivates were performed using the concerted application of ¹H 1D and ¹H, ¹³C 2D gs‐HSQC and gs‐HMBC experiments. All 1‐phenyl‐1H‐pyrazoles' derivatives were synthesized as described by Finar and co‐workers. The formylated 1‐phenyl‐1H‐pyrazoles' derivatives were performed under Duff's conditions. Copyright © 2011 John Wiley & Sons, Ltd.     

Deuterium Quantification through Deuterium‐Induced Remote 1H and 13C NMR Shifts

Partial labeling by deuterium may be quantified through simple integrations of those ¹H (200 or 400 MHz ) and ¹³C (100.6 MHz ) NMR resonances that are split into pairs by chemical shifts ⁿΔ=δ(deuterated)?δ(nondeuterated) as induced by deuterium across n>2 chemical bonds. The relative intensities of the two components of a pair are shown to be influenced to practically equal degrees by relaxation effects, so that a deuterium fraction may be determined from ¹H and ¹³C integral pairs at more remote molecular positions under the routine conditions of fast accumulative spectral acquisition.     

1H and 13C NMR analysis of 2‐acetamido‐3‐mercapto‐3‐methyl‐N‐aryl‐butanamides and 2‐acetamido‐3‐methyl‐3‐nitrososulfanyl‐N‐aryl‐butanamide derivatives

The complete assignment of the ¹H and ¹³C NMR spectra of various 2‐acetamido‐3‐mercapto‐3‐methyl‐N‐aryl‐butanamides and 2‐acetamide‐3‐methyl‐3‐nitrososulfanyl‐N‐aryl‐butanamides with p‐methoxy, o‐chloro and m‐chloro substituents is reported. Copyright © 2013 John Wiley & Sons, Ltd.     

1H and 13C NMR spectral assignments of pyridinium salts linked to a N‐9 or N‐3 adenine moiety

¹H and ¹³ C NMR spectral data of 13 new compounds containing a 4‐(dimethylamino)‐ or 4‐(pyrrolidin‐1‐yl)pyridinium moiety linked to the N‐9 or N‐3 nitrogen atom of an adenine moiety were assigned. 1D and 2D NMR experiments (DEPT, HSQC and HMBC) allowed the unequivocal identification of N‐9 and N‐3 isomers. Copyright © 2012 John Wiley & Sons, Ltd.     

1H, 13C and 15N NMR spectroscopic,x‐ray structural and ab initio/HF studies on nitramino and N‐alkylamino‐4‐nitro derivatives of pyridine N‐oxides and pyridines

The ¹H, ¹³C and ¹⁵N NMR spectra in DMSO‐d₆ were measured for eight nitraminopyridine N‐oxides, ten 4‐nitropyridine N‐oxides, four 2‐nitraminopyridines and five 4‐nitropyridines. Their chemical shift assignments are based on PFG ¹H,X (X = ¹³C and ¹⁵N) HMQC and HMBC experiments. The relative energies for the tautomers of two nitraminopyridine N‐oxides were determined by ab initio HF/6–311G** calculations. A single‐crystal x‐ray structural analysis was made for 4‐methyl‐2‐nitraminopyridine: C₆H₇O₂N₃, M = 153.15, triclinic, space group P‐1 (No. 2), a = 7.0275(4), b = 6.8034(3), c = 8.6086(5) Å, α = 103.620(2), β = 90.309(2), γ = 122.215(3)°, V = 334.11(3) ų, Z = 2. Copyright © 2003 John Wiley & Sons, Ltd.     

1H, 13C and 15N NMR investigation of a new,condensed hexahydro‐1,3,5‐triazine

Treatment of 2‐acetyl‐2‐methylcyclopentanone with hydrazine hydrate yielded a new condensed hexahydro‐1,3,5‐triazine (3b), which is the first example of the ketimine‐type trimers. A complete ¹H, ¹³C and ¹⁵N NMR assignment of the compound was achieved. Copyright © 2003 John Wiley & Sons, Ltd.     

Synthesis and NMR characteristics of N‐acetyl‐4‐nitro,N‐acetyl‐5‐nitro,N‐acetyl‐6‐nitro and N‐acetyl‐7‐nitrotryptophan methyl esters

N‐acetyl‐4‐nitrotryptophan methyl ester (2), N‐acetyl‐5‐nitrotryptophan methyl ester (3), N‐acetyl‐6‐nitrotryptophan methyl ester (4) and N‐acetyl‐7‐nitrotryptophan methyl ester (5) were synthesized through a modified malonic ester reaction of the appropriate nitrogramine analogs followed by methylation with BF₃‐methanol. Assignments of the ¹H and ¹³C NMR chemical shifts were made using a combination of ¹H–¹H COSY, ¹H–¹³C HETCOR and ¹H–¹³C selective INEPT experiments. Copyright © 2008 Crown in the right of Canada. Published by John Wiley & Sons, Ltd     

Theoretical and experimental 1H, 13C and 15N NMR studies of N‐alkylation of substituted tetrazolo[1,5‐a]pyridines

The ¹⁵N as well as ¹H and ¹³C chemical shifts of nine substituted tetrazolopyridines and their corresponding tetrazolopyridinium salts have been determined by using NMR spectroscopy at the natural abundance level of all nuclei in CD₃CN. In this paper, we report, for the first time, the N‐alkylation reaction of electron deficient tetrazolopyridines. The treatment of tetrazolopyridines 5–13 with one equivalent of trialkyloxonium tetrafluoroborate leads to a mixture of two isomers, i.e. N3‐ and N2‐alkyl tetrazolo[1,5‐a]pyridinium salts. It has been observed that the N3‐isomer is always the major isomer, except in the case of the CF₃ substituent, where the two isomers are obtained in the same amount. The quaternary tetrazolopyridinium nitrogen N3 is shielded by around 100 ppm (parts per million) with respect to the parent tetrazolopyridine. Experimental data are interpreted by means of density functional theory (DFT) calculations, including solvent‐induced effects, within the conductor‐like polarizable continuum model (CPCM). Good agreements between theoretical and experimental ¹H, ¹³C and ¹⁵N NMR were found. The combination of multinuclear magnetic resonance spectroscopy with gauge including atomic orbital (GIAO) DFT calculations is a powerful tool in the structural elucidation for both neutral and cationic heterocycles and in the determination of the orientation of N‐alkylation of tetrazolopyridines. Copyright © 2009 John Wiley & Sons, Ltd.     

NMR analysis of 6‐(2′,3′‐dihydro‐1′H‐inden‐1′‐yl)‐1H‐indene

¹H, ¹³C and two‐dimensional NMR analyses were applied to determine the NMR parameters of 6‐(2′,3′‐dihydro‐1′H‐inden‐1′‐yl)‐1H‐indene. The measurements were accomplished with 0.5 mg of the substance, this quantity being sufficient to determine the chemical shifts of all the H and C atoms, and also the appropriate coupling constants and to give the complete NMR resonance assignments of the molecule. The predicted patterns of the four different H atoms of the methylene groups of the indane structural element coincided completely with the complex patterns in the NMR spectra. Copyright © 2002 John Wiley & Sons, Ltd.     

1H, 13C and 15N NMR chemical shifts of substituted pyrazolo[1,5‐a]pyrimidines

¹H, ¹³C and ¹⁵N NMR chemical shifts of 10 substituted pyrazolo[1,5‐a]pyrimidines were assigned based on DQF ¹H, ¹H COSY, PFG ¹H, ¹³C HMQC and PFG ¹H,X (X = ¹³C and ¹⁵N) HMBC experiments and on literature data. Copyright © 2002 John Wiley & Sons, Ltd.     

1H and 13C NMR data of methyl tetra‐O‐benzoyl‐D‐pyranosides in acetone‐d6

Complete assignments of ¹H‐ and ¹³C‐NMR resonances of five methyl tetra‐O‐benzoyl‐D‐pyranosides based on ¹H, ¹³C, 2D DQF–COSY, HMQC, HMBC and HSQC–TOCSY experiments have been performed. Copyright © 2009 John Wiley & Sons, Ltd.     

1H and 13C NMR spectral assignment of N,N′‐disubstituted thiourea and urea derivatives active against nitric oxide synthase

The ¹H and ¹³C NMR resonances of seventeen N‐alkyl and aryl‐N′‐[3‐hydroxy‐3‐(2‐nitro‐5‐substitutedphenyl)propyl]‐thioureas and ureas ( 1–17 ), and seventeen N‐alkyl or aryl‐N′‐[3‐(2‐amino‐5‐substitutedphenyl)‐3‐hydroxypropyl]‐thioureas and ureas ( 18–34 ), designed as NOS inhibitors, were assigned completely using the concerted application of one‐ and two‐dimensional experiments (DEPT, HSQC and HMBC). NOESY studies confirm the preferred conformation of these compounds. Copyright © 2016 John Wiley & Sons, Ltd.     

Synthesis and 1H and 13C NMR structural analysis of cis‐ and trans‐2‐imino‐1,3‐ and ‐3,1‐perhydrobenzoxazines and their 3‐ and 1‐N‐methyl derivatives

cis‐ and trans‐2‐imino‐1,3‐ and ‐3,1‐perhydrobenzoxazines and the N‐methyl derivatives of the latter were synthesized from the corresponding cyclic 1,3‐amino alcohol with cyanogen bromide. The configurations of the studied compounds were confirmed by ¹H and ¹³C NMR spectra. All trans‐fused compounds exist in biased chair–chair conformations as expected, whereas the cis‐fused 1,3‐benzoxazines attain exclusively the O‐in conformations. The cis‐fused 3,1‐benzoxazines, especially the 1‐methyl‐substituted derivatives, tend to favor the N‐out form, obviously owing to the favorable axial orientation of this N‐methyl. Copyright © 2003 John Wiley & Sons, Ltd.     

13C‐NMR detection of STD spectra

We have investigated the use of ¹³C for the detection of saturation transfer difference (STD) NMR spectra. By detecting the STD spectrum in the ¹³C channel it is possible to eliminate the residual water signal in the STD‐NMR spectrum. We have employed an INEPT transfer in order to shift the magnetization from the proton channel to ¹³C. As a sample system to check our method we have used human serum albumin and phenylalanine. We have shown that such a transfer can be accomplished and gives reasonable signal intensities. Copyright © 2009 John Wiley & Sons, Ltd.