Chemoselective Substitution in 4-Toluenesulfonamides and Carbamates by Di-tert-butyl Dicarbonate in the Presence of 4-Dimethylaminopyridine.
作者:Leif Grehn、Ulf Ragnarsson、Anders Kjær、Carl E. Olsen、Birgitte R. Rassing、Connie N. Rosendahl、Inger Søtofte、Bengt Långström
DOI:10.3891/acta.chem.scand.52-0627
日期:——
Three novel derivatives of 1,2-ethylenediamine 1, 3 and 5 with 4-toluenesulfonyl and/or carbamate moieties have been prepared and submitted to reaction with a limiting amount of di-tert-butyl dicarbonate in the presence of catalytic amounts of 4-dimethylaminopyridine. All the reagents underwent completely selective substitution under these conditions and gave rise to the products 2a, 4 and 6 in 93-100% yields and the results were rationalized in terms of higher NH-acidity at the reaction sites. The products might be useful in synthesis of substituted 1,2-ethylenediamines. A similar approach might be applicable to many other diamines.