Mechanistic studies on nitrosation-deaminocyclization of mono-carbamoylated vicinal amino alcohols and diols: A new preparative in situ formation of ethanediazo hydroxide for the ethylation of carboxylates under mild conditions

Masumi Suzuki, Takeshi Sugai

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While the cyclization of N-carbamoylamino alcohols into oxazolidinones via the activation with NO+ underwent smoothly, we found that similar reactions of vicinal diol monocarbamates were very slow. Mechanistic studies by means of time-resolved IR measurements of the former reaction suggested that the initial O-nitrosation was the rate-determining step. Indeed, the introduction of an ethyl group on the nitrogen terminus of diol monocarbamate promoted the desired cyclic carbonate formation. The concomitantly formed ethanediazo hydroxide, the precursor of the protonated form of diazoethane, was evidenced by trapping with p-nitrobenzoic acid as an ethyl ester. The formation of ethyl ester accelerates the reaction in an irreversible manner. Based on an elaboration of the substrates and reaction conditions, 2,3-dimethyl-2,3- butanediol mono-N-ethyl-N-nitrosocarbamate, which is easily prepared in situ from the corresponding ethylcarbamate and t-butyl nitrite, was developed as a new ethylation reagent of various carboxylic acids under mild conditions.

Original languageEnglish
Pages (from-to)1217-1227
Number of pages11
JournalBulletin of the Chemical Society of Japan
Issue number6
Publication statusPublished - 2004 Jun 1


ASJC Scopus subject areas

  • Chemistry(all)

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