Deuterium oxides synthesis

Pyridine, 3-(dimethylamino)-amination, 2, 236 methylation, 2, 342 nitration, 2, 192 iV-oxide synthesis, 2, 342 Pyridine, 4-(dimethylamino)-in acylation, 2, 180 alkyl derivatives pK, 2, 171 amination, 2, 234 Arrhenius parameters, 2, 172 as base catalysts, 1, 475 hydrogen-deuterium exchange, 2, 286 ionization constants, 2, 172 methylation, 2, 342 nitration, 2, 192 iV-oxide synthesis, 2, 342... 

Various organolithium intermediates may be posmlated for the synthesis of functionalized indoles and other heterocyclic compounds, from substituted Af-allylanilines (331a-c) or the cychc analog 332, on treatment with f-BuLi. For example, in equation 81 intermediate 333, derived from 331a, was quenched with deuterium oxide. Participation of benzyne metallated intermediates, such as 334, derived from 332, is surmised in equation 82 and other processes. The products of equations 81 and 82 can be characterized by H and NMR spectra . 

An adaptation of the procedure employing deuterium oxide as the hydrolytic medium permits the synthesis of a-deuterio ketones and esters in high isotopic purity. a,a-Dideuterio... 

As a consequence, benzylic protons in a- and y-alkyl groups (but not in p-positions) are acidic and in water are in equilibrium with the corresponding methylenepyrans water at pH <5. Because the symmetric y-methylenepyrans (y-anhydrobases) are more stable than a-methylenepyrans [57], the isotopic exchange with deuterium oxide proceeds about ten times faster in y than in a, and this allows the synthesis of regiospecifically deuterated alkylpyrylium salts, which can then be converted into other deuterated compounds because the reaction with nucleophiles takes place even faster [58, 59],... 

The apparatus used is a 100-ml. round-bottomed flask equipped with a cold-finger reflux condenser and a magnetic stirring bar. This sj stem is connected to a vacuum line with five U-traps betw een the reactor and pump and two detachable bulbs from which reactants are distilled into the reactor. Prior to the synthesis the entire vacuum system is preconditioned with deuterium oxide, as has been described above (see SiD4 Procedure). 

Seguineau, P., and Villieras, J., The Wittig-Horner reaction in heterogeneous media. Part 10. Synthesis of a-deuterated functional olefins using potassium carbonate with deuterium oxide. Tetrahedron Lett., 29, 477, 1988. 

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