Catalytic deuteriation

The title compound, (4a, 5a, 17/ )-4, 5-epoxy-[6,7-2H2]-3, 17-dihydroxyandrost-2-ene-2-carbonitrile, 78,9, has been found to be of benefit in the treatment of some forms of breast cancer9. It has been synthesized10 in 6 steps as shown in equation 4. The label has been introduced into 7 in the first reaction step by catalytic deuteriation of androsta-4,6-dien-3,17-dione, 8. Similarly, [4-14C]trilostane (sp. act. 95 pCi/g, r.p. >98%, 57% overall yield) has been prepared10,11 in four steps from [4-14C]testosterone, 9. 

In an interesting paper it is revealed that di-t-butylnitroxide (DTBN) radical induces upheld contact shifts for the X-H proton donor molecules and conforma-tionally dependent downfield shifts for C—H protons in accordance with the W-rule. Methyl protons in close spatial contact with the N-H or O-H proton donor groups exhibit marked DTBN-induced downfield pseudo-contact shifts. The origin of these effects and their potential uses are discussed. Proton shifts for various monoterpenes e.g. camphor, camphor quinone, and pinocarvone) in hexafiuorobenzene are compared with the shifts obtained in other, more conventional, solvents. Unusually large couplings between the OH and adjacent CH protons have been observed for extremely pure samples of syn- and anrt-7-hydroxynorbomene in particular solvents. " The simplification in the spectra of these compounds, of 7-hydroxynor-bornadiene, and of the catalytically deuteriated (exo-addition) derivatives, with the aid of Eu(dpm)3 and Eu(fod)3 is reported in a companion communication. ... 

The IR spectra of the normal and deuteriated form have been reported [937]. It is evident that the cis form is the thermodynamically stable one [940] and it is this which is likely to be the initial species in catalytic reactions. 

Because the reaction is catalytic in ferf-butyl cation and the deprotonation/ reprotonation steps are very fast, extensive regioselective deuteriation of the isoalkane is observed at room temperature as shown by GC-MS analysis. The absence of mass 68 (d10-isobutane) and the presence of mass 64 due to S02 formation in the oxidative process are typical features in accord with the oxidative activation of the alkane and the Markovnikov-type addition of deuterons on the intermediate isobutylene (14). However, the exchange process does not take place in the presence of carbon monoxide, which traps the ferf-butyl cation and prevents deprotonation (Scheme 5.7). 

Low-energy electron bombardment of monolayers of ethylene on a silver(lll) surface brings about C—H bond fission. The H is absorbed on the surface and the vinyl radical dimerizes to yield buta-1,3-diene. Higher doses of electrons lead to the formation of ethyne Olefins can undergo catalytic oxidation when they are irradiated in the presence of silver catalysts either as silver powder or supported silver metals on anatase titania, sihca and porous glass. Irradiation under these conditions increases the reaction rate. When the surface is coated with ethene and deuterium, partly deuteriated ethene is formed on irradiation, presumably as a result of a vinyl radical reacting with deuterium. UV... 

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