SYNTHESIS OF A PYRAZOLE ISOSTERE OF PYRROLES FORMED BY THE REACTION OF THE EPSILON-AMINO GROUPS OF PROTEIN LYSYL RESIDUES WITH LEVUGLANDIN E(2)

A pyrazole isostere of pyrroles that are formed in the reaction of lev uglandin E(2) (LGE(2)) with proteins was prepared. The heterocycle was generated, together with a structural isomer, by condensation of a mo noalkylhydrazine with a 1,3-diketone. Structures of the isomeric pyraz oles were established by NOE experiments. Coupling with proteins to pr ovide antigens was achieved in the presence of alkene, carboxyl, and a llylic hydroxyl functionality by reductive alkylation with an aldehyde group at the end of an n-alkyl tether to the 1-position of the pyrazo le isostere.