Nuclear magnetic resonance spectrum, obtaining

The nuclear magnetic resonance spectrum of sodium valproate as shown in Figure 3 was obtained on a Varian Associates T-60 NMR Spectrometer in deuterium oxide containing tetramethylsilane as the internal standard. The spectral peak assignments (2) are presented in Table I. 

FIGURE 4.9 60-MHz H -nuclear magnetic resonance spectrum of Bz-D/L-Val-L-Lys(z)-OMe obtained by coupling Bz-L-Val-OH with H-L-Lys(Z)-OMe, using DCC in the presence of HOBt in dimethylformamide at 25°C.45 See text for details of quantitation. 

The C nuclear magnetic resonance spectrum of cortisone acetate was obtained on a Joel FT 100 MHz spectrometer system, using tetramethylsilane as the internal reference. To obtain the spectrum, the substance was dissolved in CDCI3. The full C-NMR spectrum is shown in Figure 8, and assignments for the observed resonance bands are provided in Table 5. 

The carbon-13 nuclear magnetic resonance spectrum of a 4.7% (w/v) solution of dorzolamide hydrochloride was obtained in deuterated dimethyl sulfoxide, and is shown in Figure 9. The spectrum was recorded using a Brucker model AM-400 NMR spectrometer. The band assignments were referenced relative to dimethyl sulfoxide-ds (39.5 ppm), and the carbon atom assignments (using the same numbering system as just described) are collected in Table 5. 

Using diethylene glycol diethyl ether, b.p. 188°, as the solvent, it has been shown from the nuclear magnetic resonance spectrum and infrared spectrum of the crudely distilled product that A,A, A"-trimethylborazine is obtained in comparable yield. However, the product cannot be separated efficiently from the solvent. 

Acid hydrolysis of 5-amino-5-deoxy-l,2-0-isopropylidene-o -D-xy-lofuranose (15) might be expected to afiFord 5-amino-5-deoxy-D-xylose, but instead, at 70 , 3-pyridinol (21) is the main product. If the acid hydrolysis of compound 15 is conducted at room temperature, there is obtained, besides 3-pyridinol (21), the crystalline hydrochloride of l-amino-l,5-anhydro-l-deoxy-D-fhreo-pentulose hydrate (22). The crystalline hydrate exhibits no carbonyl band in its infrared and ultraviolet spectra. The water content cannot be removed without decomposition of the compound, and is, therefore, water of constitution. The nuclear magnetic resonance spectrum of 22 lacks the signal characteristic of an anomeric proton. The free ketone group is, however, detectable by the preparation of a (2,4-dinitrophenyl)-hydrazone. 

In general, on reaction with lithium aluminum hydride, secondary sulfonic esters are desulfonylated, with formation of the corresponding secondary alcohol. An exception is provided in an observation by Reist and coworkers, who treated 6-0-benzoyl-l,2-0-isopropyli-dene-5-O-p-tolylsulfonyl-a-D-glucofuranose, with lithium aluminum hydride in ether and obtained a product thought to be 6-deoxy-l,2-0-isopropylidene-y3-L-idofuranose, derived from an intermediate 5,6-anhydro-L-ido derivative later, Ryan and coworkers showed, from its nuclear magnetic resonance spectrum, that the product was 5-deoxy-l,2-0-isopropylidene-a-D- t/Zo-hexofuranose. The problem has been re-examined by Overend and coworkers the repetition experiment under the conditions of Reist and coworkers afforded 5-deoxy-... 

Transfer the ether to a tared reaction tube and evaporate the solvent to leave crude triphenylmethane. Remove a sample for melting point determination and recrystallize the residue from an appropriate solvent, determined by experimentation. Prove to yourself that the compound isolated is indeed triphenylmethane. Obtain an infrared spectrum and a nuclear magnetic resonance spectrum. 

Figure 5. Carbon-13 nuclear magnetic resonance spectrum of a typical aquatic humic acid obtained from a sample of bog water.

The proton nuclear magnetic resonance spectrum of lomefloxacin mesylate obtained in D2O at 25° C is given in Figure 5 (9). The spectrum was obtained on a Bruker AM-500 NMR Spectrometer operating at 500.13 MHz and was referenced to external TSP [3-(trimethylsilyl)propionic-2,2,3,3-d4 acid]. The chemical shifts and spectral assignments are provided in Table 2 (9,10). The effect of increasing concentrations of Al3+ on the... 

The 300-MHz proton nuclear magnetic resonance spectrum of tolnaftate was obtained on a Bruker AM 300 NMR spectrometer and is shown in Figure 2. The spectrum was recorded... 

The enol ether (23) has been obtained from 2-0-methyl-D-glucose and from 2,3-di-O-methyl-D-glucose. Klemer, Lukowski, and Zerhusen isolated a crystalline form of (23) with C ]d + 16° no mutarotation was mentioned. They assumed their compound to be pyranoid by analogy with (24). The nuclear magnetic resonance spectrum of the reaction mixture from 2,3-di-O-methyl-D-glucose showed the presence of equimolar amounts... 

Attempts to prepare esterified glycals by the reduction of glycofuranosly halides with zinc in acetic acid failed, because of the reactivity of this class of compound (see p. 92). When, however, 3,5-di-0-benzoyl-2-0-(p-nitrophenylsulfonyl)-/3-D-ribofuranosyl bromide (8) in acetone is treated at 5° with sodium iodide, a facile elimination takes place and 3,5-di-O-benzoyl-1,2-dideoxy-D-er2/i/iro-pent-l-enofuranose (9) is obtained crystalline, in 72% yield. The product was characterized by identifying its hydrogenation product as the known l,4-anhydro-3,5-di-0-benzoyl-2-deoxy-D-er2/nuclear magnetic resonance spectrum, which showed clearly that the glycal structure was present. 

Comparison of the nuclear magnetic-resonance spectrum of methyl 4-0-acetylmycaroside with the spectra of some model compounds, and the failure to obtain an isopropylidene derivative of methyl a-L-mycaroside, led Foster and coworkers to propose for mycarose the ij-xylo configuration. However, the more detailed analysis made of the nuclear magnetic-resonance spectrum of di-O-acetylmycarose by Hofheinz and coworkers as well as the stereospecific syntheses of mycarose by Korte and coworkers and by Woodward and coworkers, leave little doubt that mycarose is 2,6-dideoxy-S-C-methyl-L-nho-hexose (61) and that cladinose is its 3-methyl ether (62). 

The AlP nuclear magnetic resonance spectrum of a corundum or a-AlgOg single crystal is an orientation-dependent quintet arising from the quadrupole moment = - - 0.149 (136-139). O Reilly (140) obtained the Al dispersion mode envelope (141) powder pattern spectrum which results when y-alumina is heated to 1400°, and thereby eonverted to a-AlaOs. He interpreted the line shape in terms of the Redfield modification (142,143) of the Bloch equations. 

Fig. 8.—The Partial, H Nuclear Magnetic Resonance Spectrum of Sucrose Octaacetate (8) in Solution in Acetone-rid, With a Diagrammatic Representation of the First-order Assignment of the n-Glucose Protons is Shown in A. [The set of INDOR traces (B, C, D, and E) was obtained by sequentially monitoring transitions 1, 8, 5, and 3.]...

Completely decoupled solution-phase and (2) solid-state nuclear magnetic resonance spectra obtained for benoxaprofen. The solution phase spectrum is compared with the sohd-state spectram of Form I. (The figure was adapted from data contained in Ref. 152.)... 

The carbon-13 nuclear magnetic resonance spectrum of lovastatin shown In Figure 3 was obtained using a Bruker instruments Model AM-300 NMR spectrometer and an approximately 4% w/v solution of the compound In deuterochloroform. Signal assignments are tabulated below and refer to the numbered structure shown in Section 4.2... 

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