Deuterated compounds

Homogeneous catalytic deuteration of various unsaturated 5a-spirostane derivatives is an excellent method for the preparation of side chain labeled analogs. Thus, saturation of the double bonds at positions 20(21), 23 and 24 provided the corresponding deuterated compounds (144), (145) and (146) in high isotopic purity. The preparation of (146) is a rare example of the saturation of an isolated trisubstituted double bond in the steroid field. 

Ri = N3, R.2 = H), and an equilibrium is observed in the case of the deuterated compound (59 Ri = R2 = N 02). Certain secondary amino-substituted compounds (59, 60 Rj =RNH, R2 = H) show solvent dependence of their equilibria solutions in dimethyl sulfoxide contain mainly form 59, whereas alcohols as solvents favor form 60. ... 

Problem 10.10 How might you replace a halogen substituent by a deuterium atom if you wanted to prepare a deuterated compound ... 

Shono et al. (1979) describe a method for hydro-de-diazoniations which is simple, gives excellent yields, and is claimed to show no unfavorable substituent effects (14 examples). It consists of the addition of thiophenol (7 equiv.) to a suspension of an arenediazonium tetrafluoroborate in a mixture of water and pentane (10 1) at room temperature. After the completion of N2 evolution, excess thiophenol is removed by addition of Na2C03. The usual work-up gave the corresponding hydrocarbon in 84-100% yield and diphenylsulfide. The deuterated compounds are obtained if one uses C6H5SD and D20. 

Cooper and coworkers30 measured also the absorption spectrum of transient species produced in the radiolysis of pure liquid DMSO-d6 and found the same absorption of the first two bands, however, the intensity of the absorption is about 30% larger in the case of the deuterated compound for both of the absorption bands. The intensity of the absorption is given by Ge, but as the same change was found for both bands it seems most reasonable that the 30% difference arises from a change in G rather than in e. This is similar to water, where the fraction of ions which become free ions is substantially larger for the deuterated compound32. 

The major problem in method (a) is that in ion-molecule interchange, considerable momentum in the direction of travel of the incident ion is imparted to both final products. Hence, in a perpendicular type apparatus only transfer of low weight particles can be observed at all and only at very low velocities of the incident ions (1, 9, 10, 11, 12, 13, 19, 20, 23, 27). Cross-sections cannot be measured. The value of these investigations is that some ion-molecule reactions—e.g., proton transfer and hydride ion transfer—can be identified. The energetics and the competition between charge exchange and ion-molecule reactions can be discussed, and by using partially deuterated compounds, one can obtain a detailed picture of the reaction. 

Thierrin J, GB Davis, C Barber (1995) A ground-water tracer test with deuterated compounds for monitoring in situ biodegradation and retardation of aromatic hydrocarbons. Ground Water 33 469-475. 

P212121 Z = 4 Dn = 1.540 R = 0.032 for 1,051 neutron intensities at 123 K. This was an experiment similar to that of the partially deuterated / -L-arabinopyranose already described. The results here were also negative. The room-temperature, neutron-diffraction structure of the un-deuterated compound had been determined previously.11... 

Denitration of nitro compounds with Bu3SnD provides an elegant method for the synthesis of deuterated compounds.98 Recently, the synthesis of deuterium labeled plant sterols has been reported (see Eq. 7.78).99... 

The simplest reaction of zirconacyclopentadienes is their hydrolysis. It is characteristic for organo-early transition metal compounds the metal—carbon bond is easily hydrolyzed with acids to give free organic compounds. Similarly, deuterolysis of zirconacyclopentadienes, rather than protonolysis, affords deuterated compounds as expected (Eq. 2.9). The position of the deuterium is indicative of the position of the metal—carbon bond in the organozirconium compound. 

The power of the system to overcome the problems associated with coeluting compounds is demonstrated in conjunction with the use of deuterated (or13C-labelled compounds) as internal standards. Such techniques could not be used in conventional gas chromatography as the deuterated compounds often co-elute, making quantification difficult if not impossible. With the ion-trap detector, however, it is easily possible to differentiate between the ions arising from the different compounds and the intensities of these ions could then be used for quantification of the compounds involved. The application of such techniques can be shown by... 

The determination of alkyltrimethyl ammonium compounds with the general formula RN (CH3)3X surfactant were performed using CF-FAB and ESI. The compounds examined were dodecyl-, tetradecyl-, and hexadecyl-trimethyl ammonium compounds dissolved in water. The product ion spectra of dodecyltrimethyl ammonium compound and its methyl-deuterated homologue were presented. The product ion at m/z 60 [(CH3)3NH]+of the non-deuterated compound at m/z 228 was the only ion that shifted after deuteration to m/z 69 [38],... 

Further, a large number of examples with simple alkyl substituents [168, 171, 176-184], cyclic alkanes [185], aryl substituents [177, 186-192], olefmic substituents [78, 177, 193-196], deuterated compounds [172], thioether groups [171], ester groups [197], orthoesters [198, 199], acetals [168, 182, 200-204], silyl-protected alcohols [198, 205-211], aldehydes [212], different heterocycles [213-217], alkyl halides [218, 219] and aryl halides [192, 220-223] have been reported. A representative example is the reaction of 92, possessing a free hydroxyl group, an acetal and a propargylic ether, to 93 [224] (Scheme 1.40). 

Although DIOS-MS is mainly a tool for qualitative analysis, many examples have shown that quantitative analysis is possible when internal standards are used. These may either be isotope-labelled - mostly deuterated - compounds or structurally related analogues. For example, subsequent to electrospray deposition, amino acids such as phenylalanine and tyrosine have been successfully quantified by means of DIOS-MS using their deuterated analogues as internal standards. 

As can be seen, the pathway from the cyclohexadienone to the ortho-rearranged phenol does not imply a jump over an energy barrier (34 kcal/mol), but a tunneling from the vibrational energy levels located at E(vo) = 0 kcal/mol and E(vi) = 3.9 kcal/mol (4.4 kcal/mol for the deuterated compound). Analogous results have been reported for the photo-Fries rearrangement of 2,4-dimethoxy-6-( ara-tolyloxy)-v-triazine (28) to give 2,4-dimethoxy-6-(2-hydroxy-5-meth-ylphenyl)-v-triazine (29) (Scheme 11) [43]. 

Nantes following the general methodology of Gumming and Carver (5). All the NOE calculations were performed for a previously described (, ) hexa-deuterio version of Manal-3ManP because the observed NOE S do not overlap and are much larger for this disaccharide than those for the undeuterated version. Thus the NOE s for the deuterated compound can be much more accurately measured. 

NOE Measurements. The one-dimensional NOE data were collected at 300 MHz on a Bruker AM-300 NMR spectrometer operating at 300 K. Because the relaxation times for the protons of the hexa-deuterated compound ranged from O.A s to 3.8 s, delays of 20 s. were used between scans. Values for the T s were also measured and found to range from 0.32 s to 1.5 s all values were consistent with a rotational correlation time of 1.1x10 s. 

Deuteration of one end of the allyl moiety in these compounds removes the equivalence of the two positions and in place of the single line for the terminal position, two separate absorptions should appear (W). One, in the normal decoupled spectrum, is a singlet for the hydrogen substituted carbon, and the other a weak quintet for the deuterated end which would be difficult to observe. These two signals would bracket the normal singlet. If a mixture of deuterated and undeuterated allyl compound is used, therefore, two easily observable peaks should appear, one in the normal position, the other shifted. In the spectra of allyllithium and allylsodium the line from the deuterated compound appeared I and 11 Hz upfield respectively, at 0°C, of the normal lines. The potassium compound only showed a somewhat broadened line. At -80°C the separation for allyllithium was 22 Hz. 

The IR spectra of the CF3S derivatives of urea, as well as of the deuterated compound, have been discussed at great length (71). 

A number of ex situ spectroscopic techniques, multinuclear NMR, IR, EXAFS, UV-vis, have contributed to rationalise the overall mechanism of the copolymerisation as well as specific aspects related to the nature of the unsaturated monomer (ethene, 1-alkenes, vinyl aromatics, cyclic alkenes, allenes). Valuable information on the initiation, propagation and termination steps has been provided by end-group analysis of the polyketone products, by labelling experiments of the catalyst precursors and solvents either with deuterated compounds or with easily identifiable functional groups, by X-ray diffraction analysis of precursors, model compounds and products, and by kinetic and thermodynamic studies of model reactions. The structure of some catalysis resting states and several catalyst deactivation paths have been traced. There is little doubt, however, that the most spectacular mechanistic breakthroughs have been obtained from in situ spectroscopic studies. 

The use of MALDI-MS for the measurement of low molecular mass compounds is widely accepted now [61], but quantification remains problematic. The main problem is the inhomogeneous distribution of the analytes within the matrix [62]. This leads to different amounts of ions and therefore to different signal intensities at various locations of a sample spot. The simplest and most effective way to overcome this problem is the use of an appropriate internal standard [63]. The use of deuterated compounds with a high molecular similarity to the analyte as internal standards leads to a linear correlation between relative signal intensities and relative amount of the compound to be quantified (Fig. 4b) [64]. Using this approach it is possible to quantitate substrates and products of enzyme catalyzed reactions. Two examples were shown recently by Kang and coworkers [64, 65]. The first was a lipase catalyzed reaction which produces 2-methoxy-N-[(lR)-l-phenylethyl]-acetamide (MET) using rac-a-... 

When the temperatures during the CVD process of (fBuOAlH2)2 (and the corresponding deuterated compound) are raised to 450 °C at the target surface, the products of the reaction change (Eqs. 6 and 7). 

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