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Paper | Regular issue | Vol 34, No. 2, 1992, pp.303-314
Published online, 1st January, 1970
DOI: 10.3987/COM-91-5913
The [2-(Trimethylsilyl)ethoxy]methyl Function as a Suitable N-1 Protecting Group in Lithiation Reactions with Pyrazoles and 1,2,4-Triazoles

Natalie Fugina, Wolfgang Holzer,* and Michael Wasicky

*Institute of Pharmaceutical Chemistry, University of Vienna, Währinger Strasse 10, A-1090 Vienna, Austria

Abstract

Metallation of 1-[2-(trimethylsilyl)ethoxy]methyl-1H-pyrazole or 1-[2-(trimethylsilyl)ethoxy]methyl-1H-1,2,4-triazole, respectively, with one equivalent of n-BuLi followed by reaction with appropriate electrophiles leads to 5-substituted 1-[2-(trimethylsilyl)ethoxy]methyl-1H-pyrazoles and 5-substituted 1-[2-(trimethylsilyl)ethoxy]methyl-1H-1,2,4-triazoles. Deprotection can be achieved either by heating with aqueous ethanolic HCl or by treatment with anhydrous tetrabutylammonium fluoride.