Tritiated diazomethane

Diazomethane is a valuable reagent for one-carbon extension of acyl halides and anhydrides, as well as for ring expansion reactions of cyclic ketones " . It is also widely used in small-scale organic synthesis for the esterification of carboxylic acids and the etherification of phenols, enols and alcohols " . In these reactions, however, CH2N2 installs the label in positions that are potentially metabolically labile and usually unsuitable for use in metabolism smdies. For in vitro studies where metabolism is not an issue, tritiated diazomethane is usually preferred because of its higher specific activity. 

In spite of its broad synthetic potential and in contrast to its carbon-14 isotopomer, diazo [ HJmethane has so far found only very few applications. It was originally prepared by basic hydrolysis of A-nitroso-A-[ H]methyl urea in specific activities of 0.5-2 Ci/mmol, following classical synthesis procedures. A newer procedure that makes use of the tritiodesilyla-tion of (trimethylsilyl)diazomethane with tetrabutylammonium fluoride in the presence of tritiated water is discussed in Section 4.4.1. Diazo[ H]methane thus generated in situ can be... 

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