- Efficient, scalable and economical preparation of tris(deuterium)- and 13C-labelled N-methyl-N-nitroso-p-toluenesulfonamide (Diazald) and their conversion to labelled diazomethane
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A method for the preparation of multi-gramme quantities of N-methyl-d3-N-nitroso-p-toluenesulfonamide (Diazald-d3) and N-methyl-13C-N-nitroso-p-toluenesulfonamide (Diazald-13C) and their conversion to diazomethane-d2 and diazomethane-13C, respectively, is presented. This approach uses robust and reliable chemistry, and critically, employs readily commercially available and inexpensivemethanol as the label source. Several reactions of labelled diazomethane are also reported, including alkene cyclopropanation, phenolmethylation and α-diazoketone formation, as well as deuteriumscrambling in the preparation of diazomethane-d2 and subsequent methyl esterification of benzoic acid.
- Shields, Samuel W.J.,Manthorpe, Jeffrey M.
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p. 674 - 679
(2015/01/16)
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- Partial oxygen migration in the photochemical wolff rearrangement - α-Oxocarben-Oxiren-isomerization or intermolecular mechanism?
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Crossover experiments between isotopomeric species of 2-diazo-1-oxo-1-phenylethane (18O, 13C, D) establish beyond doubt that the oxygen migration accompanying the photochemical Wolff rearrangement is not the result of intermolecular
- Haiss, Peter,Zeller, Klaus-Peter
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p. 595 - 605
(2007/10/03)
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- Methyl Trideuteriomethyl (E)-(α-Bromoarylidene)malonates: Simple Stereochemical Probes in Nucleophilic Vinylic Substitution near the Retention/Stereoconvergence Borderline
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Methyl trideuteriomethyl (E)-(α-bromo-p-methyl- and -p-nitrobenzylidene)malonates (4 and 5) were prepared.These electrophilic bromo olefins are activated to vinylic substitution by ywo chemically identical but isotopically distinguishable CO2Me groups.The
- Rappoport, Zvi,Gazit, Aviv
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p. 6698 - 6710
(2007/10/02)
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- Onium Ylide Chemistry. 4. Alkylhalonium Methylides
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Alkylhalonium methylides were generated by two independent routes, proving their formation through derived product analysis.The reaction of singlet methylene, produced by photolysis of diazomethane, with methyl and ethyl halides gives in competition with C-H insertion evidence of methylenation of halogen atom, i.e., alkylhalonium methylide formation.The unstable halonium methylides are immediatly protonated or alkylated in the reaction medium to give dialkylhalonium ions which then undergo cleavage to the corresponding alkyl halides.Methyliodonium methylide was also generated via the deprotonation of dimethyliodonium hexafluoroantimonate with sodium hydride in competition with the expected methylation of fluoride and hydride, giving the major products.Subsequent methylation of the methyliodonium methylide by excess dimethyliodonium ion gives methylethyliodonium ion followed by cleavage leading to the formation of ethyl halides and via hydride reduction to ethane, respectively.Attempted formation of alkylhalonium methylides via fluoride cleavage of methylhalonium hexafluoroantimonates was unsuccessful due to ready disproportionation of the halonium ions.
- Olah, George A.,Doggweiler, Hans,Felberg, Jeff D.
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p. 4975 - 4978
(2007/10/02)
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- Stereochemical studies on the reactions catalyzed by the PLP-dependent enzyme 1-aminocyclopropane-1-carboxylate deaminase
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The stereochemical course of 1-aminocyclopropane-1-carboxylate deaminase which catalyzes the fragmentation of the cyclopropane substrate to alpha -ketobutyrate and ammonia has been unraveled with the help of substrates stereospecifically labeled with deuterium and/or tritium, and this has afforded important information about the process occurring at the active site during enzymatic conversion.
- Liu,Auchus,Walsh
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p. 5335 - 5348
(2007/10/07)
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