Deuterated compounds Acetone

The H NMR spectra of organic compounds are usually obtained in an aprotic solvent at concentration levels of a few percent. The most widely used solvent is deuterated chloroform (CDC13), sufficiently polar to dissolve most organic compounds. Acetone-r/6 (C3D60), methanol-e 4 (CD3OD), pyridinc-r/5 (C5D5N) and heavy water (D20) are also used. 

Data for the primary kinetic isotope effect, corresponding to the replacement of the simple aldehyde or ketone by the fully tr-deuterated compound, are roughly in agreement with transition state models in which the proton is not far from being half-transferred. For example, the value observed [6.5 (Hine et al., 1972) 6.7 (Toullec and Dubois, 1974)] for fully dissociated acid-catalysed enolisation of acetone are close to the theoretical maximum value which can be calculated for half proton transfer. 

In synthetic organic and organometaUic chemistry, solution-state NMR means a 300—500 MHz NMR spectrometer, high-precision glass sample tubes, 2 ml of deuterated solvent (typicaUy fully deuterated chloroform, acetone, benzene, or dichlorobenzene), several milligrams of pure sample, and a basic suite of H and NMR experiments [3 7]. With several hours of spectrometer time and data interpretation, the stuctures of new compounds with molecular weights up to 2000 Da can be determined, espedaUy when analyzed along with results from NMR databases and mass spectroscopy. 

Unlike ketones and alkenes, aliphatic imines are reluctant to undergo photoinduced (2 + 2) cycyoadditions. For example, the cyclohexanimines of acetone and its derivatives were studied149. Compound 155 undergoes photoaddition with deuterated acetone, but the oxazetidine 156 decomposes to acetone and hexa-deuterioimine 157 (equation 89). 

Deuterated troponoids, e.g., 32 and 33 [Scheme 9 80BSF(1)327], result from condensations involving mono- or dideuterated diformyl compounds (D enters positions 4 and 8 in 32) and/or perdeuterated acetone (D enters... 

One of the best procedures for the synthesis of 1,3-diphenylbenzo[c]furan (138) consists of the reaction of 3-phenylphthalide (102) with phenylmagne-sium bromide, 2- especially when the reaction mixture is worked up in the presence of hydroquinone. The primary product can be isolated as colorless crystals with mp 145°C (decomposition above 100°C) in the presence of acid this unstable compound loses water very rapidly. The stereochemistry of the hydroxyphthalan is not known with certainty presumably the cis isomer (137a) is formed first. In deuterated acetone equilibrium with the trans isomer (137b) is established. ° For the synthesis of 1,3-diphenylbenzo [cjfuran, the hydroxyphthalan need not be isolated. 

Fifolt [ 130] reported this chemical shift additivity method for fluorobenzenes in two deuterated solvents d6 acetone and d6 dimethyl sulfoxide (DMSO) Close correlations between experimental and calculated fluorine chemical shifts were seen for 50 compounds Data presented in Table 18 result from measurements in deuterochloroform as (he solvent [56] Fluorine chemical shifts calculated by this additivity method can be used to predict approximate values for any substituted benzene with one or more fluorines and any combination of the substituents, to differentiate structural isomers of multisubstituted fluorobenzenes [fluoromtrotoluenes (6, 7, and 8) in example 1, Table 19], and to assign chemical shifts of multiple fluorines in the same compound [2,5 difluoroamline (9) in example 2, Table 19] Calculated chemical shifts can be in error by more than 5 ppm (upfield) in some highly fluonnated systems, especially when one fluonne is ortho to two other fluorines Still, the calculated values can be informative even in these cases [2,3,4,6-tetrafluorobromobenzene (10) in example 3, Table 19]... 

The exact mechanism of propylene glow discharge polymerization is not known. The presence of a terminal acetylene (presumable propyne) in the gaseous products of propylene polymerization was indicated by the interaction of the cold trap gaseous condensates with 1% alcoholic or ammonlacal AgNO sol.(22) after the polymerization was over. An immediate formation of an explosive silver acetyllde was detected. Intermediate formation of propyne is also indicated by the IR spectra of the yellow relatively less volatile liquid left in the cold trap after the polymerization was over. Sharp but weak absorptions at 3310 cm l and 1270 cm are indications of a substituted acetylenic compound. The IR spectra of the yellow liquid also points to the presence of mono, dl- and trl-substituted aromatic compounds in the mixture (i.e. sharp absorption bands at 3080 cm l, 1640 cm l, 920 cm , 810 cm and a multiple band in the 1000-1120 cm l region are observed). The NMR spectra in deuterated acetone indicated the presence of an aromatic nucleus in the yellow liquid obtained from the cold trap. The formation of aromatic compounds can be explained if a propynyllc Intermediate is involved. 

After drying, usually overnight, the sample Is transferred with the deuterated solvent (preferably acetone or methanol) Into the micro NHR tube. The qualities of the NMR solvents often fluctuate (even from the same manufacturer). Therefore, each batch of solvent Is checked by NMR spectroscopy for contaminants prior to use with an unknown compound. 

The most widely used solvent is deuterated chloroform (CDCI3) which is sufficiently polar to dissolve the majority of organic compounds. Also used are acetone-d5(C3DgO), methanol-d4(CD30D, pyridine-d5(C5D5N) or heavy water (D2O). 

Most NMR experiments with resveratrol oligomers are performed in deuterated acetone. This solvent has proven itself ideal for this class of compounds due to the high degree of solubility of the resveratrol oligomers and the lack of overlap between the solvent and analyte peaks. The second most commonly employed solvent is deuterated methanol, with deuterated dimethyl sulfoxide and pyridine used only occasionally. In some cases the NMR spectra of some O-methyl and O-acetyl resveratrol oligomer derivatives have been collected in deuterated chloroform [51,57,93,103]. 

Figure 7.19 shows the H NMR spectra of water and methyl groups in acetone and DMSO (for the proton-containing solvents) and only water in the case of the deuterated solvents. In contrast to nonpolar solvents, these organic compounds possess high electron-donor ability and can form mixtures with water at any concentration in the bulk. Water dissolved in these organics at excess of them is characterized by the chemical shifts at 8h=2.5-3.0 ppm. 

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