1H and 13C NMR spectra

Sketch what you might expect the 1H and 13C NMR spectra of the following compound to look like (yellow-green = Cl) ... 

Although the o-xylylene complex is thermally unstable, it was characterized at — 50 °C by its 1H- and 13C-NMR spectra showing the exocyclic methylene at 5 = 5.04,4.42 ppm (JH) and 5 = 144.8 ppm (13C) using C6D5CD3 as the solvent. Its reaction with benzoyl chloride on the exocyclic carbon leaves a very acidic methylene group which transfers a proton onto the adjacent methylene unit. The double bond is benzoylated again in in situ and a di-cation of the [bis(arene)Fe]2+ type is obtained [47] Scheme VIII. 

The 1H and 13C NMR spectra of the three fluorides are given in Figures 4 and 5 respectively. The peak assignments for various groups in each compound are given in Tables II and III, while calculated and observed peak ratio values are given in Tables IV and V. 

Analysis of the 1H and 13C NMR spectra of the tin complexes, being derivatives of various di-Schiff bases, [46] has revealed the dependence of the position of tin centre on the type of linker between the two imine units and the metal coordination number.110... 

Hufford et al [57] used proton and 13C NMR spectrometric data to establish the novel sulfur-containing microbial metabolite of primaquine. Microbial metabolic studies of primaquine using Streptomyces roseochromogenus produced an A-acety-lated metabolite and a methylene-linked dimeric product, both of which have been previously reported, and a novel sulfur-containing microbial metabolite. The structure of the metabolite as an S-linked dimer was proposed on the basis of spectral and chemical data. The molecular formula C34H44N604S was established from field-desorption mass spectroscopy and analytical data. The 1H- and 13C NMR spectra data established that the novel metabolite was a symmetrical substituted dimer of primaquine A-acetate with a sulfur atom linking the two units at carbon 5. The metabolite is a mixture of stereoisomers, which can equilibrate in solution. This observation was confirmed by microbial synthesis of the metabolite from optically active primaquine. 

The so-prepared compounds are very sensitive toward air and moisture, in particular in solution. 1H- and 13C-NMR spectra prove the formation of 1 1 adducts of the type dmap—M(R2)E(Tms)2. The proton resonances of the dmap molecule are shifted to higher field, as was observed for similar borane adducts... 

IR spectra were recorded on a Perkin-Elmer 577 instrument 1H and 13C NMR spectra were recorded on a Varian XL 200 instrument. GC analysis were performed on a Hewlett-Packard 5880 instrument, FI detector, equipped with a Methyl Silicone fluid capillary column (35 m), by using n-esadecane as internal standard. GC-MS analysis were performed using a Hewlett-Packard 5995 C instrument. 

Exercise 9-43 Figure 9-50 shows the 1H and 13C nmr spectra of a compound C6H10O. With the aid of these spectra, deduce the structure of C6H10O. It will be seen that the 13C spectrum is quite simple, even though the proton spectrum is complex and difficult to interpret. 

The reaction of 1-azidoadamantane with ethyl acrylate affords exclusively a 4-substituted triazoline.155 The assigned regiochemistry is supported by 1H-and 13C-NMR spectra. The H-NMR spectral characteristics of the triazoline ring protons are similar to those reported for the corresponding adduct from phenyl azide.32, 3C-NMR spectra reveal a characteristic triplet at 8 61.9 assignable to C-5. 55 Different NMR techniques have been used in structure assignments of isoindolo[2,l-c]-A2-triazolines,324 spiroanthrone-triazolines,193,194 5-heteroaryl-substituted A2-1,2,3-triazolines,329 and some l-fluoro-(5-trifluoromethyl)-A2-l,2,3-triazolines.356... 

The observed fivefold symmetry in the 1H and 13C NMR spectra even at very low temperature (— 150°C) with no line broadening leaves only two alternatives for the structure of the dication the nonclassical fivefold symmetrical, static structure 437 or... 

Chemical two-electron oxidation of the corresponding 1,2-dithiin resulted in the formation of a stable solution of dication 95 (no decomposition was observed at 18°C for months)256 [Eq. (4.73)]. 1H and 13C NMR spectra of the dication exhibited resonances at considerably lower fields compared with those of the neutral starting material suggesting aromatic stabilization. Calculated geometries (B3LYP/6-31G ) indicate a planar ring and calculated chemical shifts are in fair agreement with observed values. The related 1,4-dithiin dication was also characterized.257... 

The unusual telluronium dication analogous to 79 [see Eq. (4.47)] has also been prepared by Furukawa and Sato.197 198 The 1H and 13C NMR spectra are consistent with those of dication 79. The X-ray crystallographic analysis of the triflate salt indicates, however, a nearly hexagonal structure for the telluronium dication. This results from the strong interaction of the anions with the Te center forming ahexavalent structure. 

When a stream of oxygen containing 15% ozone was passed through a solution of isobutane in HSC F-SbFs-SOiClF solution held at —78°C, the colorless solution immediately turned brown in color. 1H and 13C NMR spectra of the resultant solution were consistent with the formation of the dimethylmethylcar-boxonium ion in 45% yield together with trace amounts of acetylium ion (CH3CO+). Further oxidation products (i.e., acetylium ion and C02) were reported to be observed in a number of reactions studied. Such secondary oxidation products, however, are not induced by ozone. Similar treatment of isopentane, 2,3-dimethylbutane, and 2,2,3-trimethylbutane resulted in formation of related carboxonium ions as the major products (Table 5.37). 

Finally, a fourth class of alkaloids has been discovered, apparently specific to the leaves of P. Lyallii (57). It consists of two unseparable products, 37 and 38, in the ratio 2 to 1, which readily give lyaloside (23) on mild methanolysis, along with two esters, namely, methyl ferulate and methyl sinapate (39 and 40, respectively). Elucidation of their structure was essentially based on NMR considerations (57). Graphical correlations between 1H- and 13C-NMR spectra, associated with analysis of the residual constant coupling during a step by step [200 Hz per 200 Hz from 0 (TMS) to 2000 Hz] off-resonance procedure, permitted the precise assignment of all the carbon atoms of the products (58). 

Nuclear magnetic resonance (NMR) spectrometry [4] Both the 1H NMR and 13C NMR spectra of zaleplon have been obtained in DMSO- as a solvent and using tetramethylsilane as the internal standard (IS). The assignments for both the 1H and 13C NMR spectra make use of the following numbering scheme ... 

Use 1H and 13C NMR spectra with other data or spectra to deduce a structure. 

Nuclear magnetic resonance spectroscopy is a powerful technique for investigating structure of biomolecules. The 1H- and 13C-NMR spectra of L-a-amino acids have been compiled (Wiithrich, 1986) and can be retrieved from SDBS. Design a database for 1H- or 13C-NMR data that can be used in the identification of amino acids. 

Temperature variations of 1H- and 13C-NMR spectra of allyl and pentadienyl compounds of the alkali metals have given information about barriers to rotation about the C—C bonds. The endo and exo isomers of the allyl anions [Eq. (1)] are formed stereospecifically at low temperatures from Z-and E-alkenes, respectively (75,76). 

The tin complexes LXIXa-d are colorless, crystalline, and very air-sensitive compounds, monomeric in solution and in the gas phase. The species LXIXc,d tend to disproportionate in solution. Averaged resonance signals with no (117,119) tin coupling are observed in the 1H- and 13C-NMR spectra of these compounds (228 30). 

The 1H and 13C NMR spectra indicate the absence of regioisomers. Solubility in pentane... 

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