Deuterated acetophenone

FIGURE 6.42 Oxidation of 3-oxa-chromanol 58 in the presence of 1 equivalent of water mechanistic study hy means of selectively deuterated starting material. The initially formed ortho-quinone dimethide 63 rearranges into styrene derivative 64, which then reacts with water to provide acetophenone 61. 

TABLE 5.6. Calculation of the Abundance of Isotopic Peaks in the Mass Spectrum of Deuterated Acetophenone... 

Recently, a series of derivative ligands, [L19]4-—[L23]4-, has been reported (32,62), where the acetophenone chromophore in [L18]4- is replaced by a dipyrazolylpyridine chromophore. These form lanthanide complexes that are stable in aqueous solution, and which possess very promising photophysical attributes. The europium and terbium complexes of all these ligands have long lifetimes (1.3-1.4 ms for europium and 2.3-2.8 ms for terbium) in water that are largely unchanged by solvent deuteration, indicating the effective exclusion of solvent from the primary coordination sphere. 

Deuterated standards (dio-xylene ds-phenol ds-acetophenone cfc-phenylethanol cfc-nitrobenzene ds-propiophenone dg-naphthalene cfe-acridine di2-perylene) accumulator column 9 55-93 78 4-21 10 d... 

To specify the position and the nature of the transferred hydride, the reaction was performed with 2-propanol-dj as solvent/donor, sodium 2-propylate as base and Fe3(CO)12/PPh3/TerPy as catalyst under optimized conditions. In the transfer hydrogenation of acetophenone a mixture of two deuterated 1-phenylethanols was obtained (Scheme 4.7, 9a and 9b). The ratio between 9a and 9b (85 15) indicated a specific migration of the hydride, albeit some scrambling was detected. However, the incorporation is in agreement with the monohydride mechanism, implying the formation of metal monohydride species in the catalytic cycle. 

Carbonyl groups are most significant in triplet state photochemistry. Spectroscopic studies include time resolved ESR studies of enols of -hydroxybenzaldehyde 2 energy transfer from acetophenones to 9, 1 0-d ibr omoa n t hr a ce ne (S.,) which involves higher triplet states of the donor283, two photon excitation of substituted triplets of acetophenone , transient resonance Raman spectra of deuterated benzophenones , and diffuse reflectance of... 

Mercury as an environmental pollutant is sometimes found as dimethyl mercury. Look up the natural abundance of the mercury isotopes and calculate the pattern to be expected in the molecular-ion region. The methyl group in acetophenone can be deuterated by refluxing a mixture of acetophenone and D2O with a little base catalyst. 

The differential method has also been used to determine deuterium isotope effects in the formation of the 2,4-dinitrophenylhydrazones of acetophenone-mef l-dg and other deuterated ketones (Baaen et ah, 1964), using carbon-14 as the tracer. The procedure requires that the isotope effects caused by the carbon-14 itself be known, and these were determined in separate experiments. Known mixtures of deuterated and undeuterated species were then prepared—one of which was always labeled with carbon-14— and the rate of change of carbon-14 content as a function of fraction of reaction was determined by removing small aliquots of reaction product at selected known intervals (or fractions f) of reaction. The data were then fitted to equations (35) or (36) by means of linear or non-linear least-squares codes, respectively, with an IBM 7090 computer. Some typical experimental results are given in Table 7. 

Chiral ruthenabicyclic complexes, where a BINAP and a diamine provide chelation to produce the rings, provide excellent catalysis of hydrogenation of ketones, giving >99% ee and turnover frequency of 35000min for acetophenone. Spectroscopic and deuteration experiments suggest that the ruthenabicyclic structure is retained throughout. ... 

The rearrangement is found to be of intramolecular nature. The radical pair remains in the solvent cage and their recombination in the cage affords the acyl migration products, while hydrogen abstraction by the phenoxy radical from the solvent leads to the formation of phenol as by-product. When the reaction of phenyl acetate was carried out with deuterated phenol in methanol, the major products were ortho- and para-hydroxy acetophenones and phenol. Only trace amounts of crossover products were obtained [42]. The presence of methoxy substiment at meta- and para-positions increases the yield of ortho-Vries product [43]. For example, 39 gives 40. 

Scheme 18 Catalytic transfer hydrogenation and deuteration of acetophenone. ...

The uncatalyzed thermal oxidation of atactic polystyrene has been studied extensively, including main chain deuterated derivatives. Such studies are usually conducted around 475 K over the course of hours. However, in preliminary infrared studies with cast films of anionic polystyrene (molecular weight 4,(X)0) on a AgQ plate, carbonyl bonds were first detected after 10 minutes heating in air at 403 Oxidation is an exothermic reaction. We have not located a measured heat of oxidation. However, comparisons with the heats of combustion for ethylbenzene and acetophenone in the Handbook of Chemistry and Physics indicate a liberation of 102 kcal/mol for the oxidation of ethylbenzene to acetophenone. The course of oxidation of polystyrene is a complex chain reaction but we will assume a net heat of liberation of = 100 kcal/mol to hold. 

Another example of 1,5-biradicals disproportionating to enols is provided by o-(2,4,6-triisopropylphe-nyl)acetophenone, which forms an enol that is long lived due to its steric congestion. Table 58.8 indicates that the cychzation yield of the compound is larger for the a-deuterated form, thanks to a primary isotope effect on the biradical disproportionation. However, Lewis-base solvents greatly diminish cychzation yields, probably because the solvated OH group presents a steric barrier to cychzation. 

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