Synthesis of N-urethane protected α-aminoalkyl-α-cyanomethyl ketones; Application to the synthesis of 3-substituted 5-amino-1H-pyrazole tethered peptidomimetics

摘要

The preparation of N-protected amino/peptide α-cyanomethyl ketones through cyanation of the corresponding α-bromomethyl ketones is described. The utility of the resulting α-cyanomethyl ketones in the synthesis of 3-substituted-5-amino-1H-pyrazoles has also been demonstrated. In both steps a wide range of N-protected amino/peptide acids has been employed and the products are obtained in good yield. The enantiomeric purity of both the α-cyanomethyl ketones and pyrazoles were confirmed by chiral HPLC analysis of the corresponding Z-protected d- and l-Ala-OH as model substrates. The synthesis of peptide pyrazolecarboxamides is also delineated.