Synthesis, Reactivity, And Applications Of P-nitrophenyl 3-diazopyruvate And 3-diazopyruvamides (cross-linking, Cyclopeptides).

Abstract

p-Nitrophenyl 3-diazopyruvate (PNPDAP) has been developed as a reagent for the modification of proteins, and as a synthon for organic synthesis. PNPDAP alkylates primary and secondary amines to form 3-diazopyruvamides in high yields. 3-Diazopyruvamide derivatives have been formed from a wide variety of amines including aromatic amines, amino acids, and peptides. 3-Diazopyruvamides undergo photolysis and Wolff rearrangement at 300 nm to produce a ketene amide which efficiently acylates nucleophilic species to form malonic acid amide derivatives. PNPDAP was made available to a number of researchers and has been found to be an efficient photoactivatable cross-linking agent. Metal-catalyzed decompositions of 3-diazopyruvamides to produce carbenoids were not found to be synthetically useful. Lewis acid catalyzed addition of hydroxy nucleophiles to the diazoketone forms 3-aryloxy-, 3-alkyloxy-, and 3-acyloxypyruvamide derivatives. Cyclization of a 3-diazopyruvamide tripeptide by formation of the aryl ether bond of a cyclopeptide ring skeleton failed. 3-Diazopyruvamides react efficiently with hydrochloric acid to produce 3-chloropyruvamides which rapidly alkylate thiol nucleophiles. Reactions aimed at the development of 3-chloropyruvamides as affinity labels and cross-linking agents were investigated. A model 3-chloropyruvamide cross-linking agent could be cleaved after reaction with p-thiocresole, by oxidation with hydrogen peroxide. A family of hetero-bifunctional, photoactivatable 3-diazopyruvamide cross-linking agents was synthesized from amino acids. A cleavable, photoactivatable cross-linking agent as synthesized from cystamine. All of these reagents and the 3-chloropyruvamide reagent were reacted with rabbit muscle aldolase to form dimeric cross-linked species.