Papain-catalysed synthesis of Z-l-aminoacyl-antipyrine amides from Z-protected amino acid esters and 4-aminoantipyrine

The enzymatic synthesis of Z-l-aminoacyl-antipyrine amides from Z-protected amino acid esters and 4-aminoantipyrine (AAP) was accomplished by papain in aqueous-organic and biphasic media as well as in suspension. Product yields of 80% and 68% for Z-Gly-AAP and Z-Ala-AAP, respectively, could be obtained. The products were purified and characterised by polarimetry and NMR. The following results expand our knowledge of the catalytic potential of proteases, in particular the suitability of papain to accept as nucleophile the 1,2-amino ketone moiety of appropriate heterocyclic compounds.