Enzymatic nitration of the oleic acid derivatives: Synthesis, isolation and characterization

Abstract

We have synthesized the nitrated derivatives of the oleic acid based on enzymatic synthesis. Under catalysis conditions of horseradish peroxidase (HRP)/H 2 O 2 /NO, nitroalkenes are the main products. Due to the good selectivity, the reaction of HRP/H 2 O 2 /NO with unsaturated fatty acids derivative may represent a convenient and straightforward route for the small scale preparation of nitrated lipid products of potential biological interest. • We have synthesized the nitrated derivatives of the oleic acid based on chemical synthesis and enzymatic synthesis. • Under biological catalysis conditions, nitroalkenes are the main products and there are few by-products. • Due to the good selectivity, the reaction of HRP/H 2 O 2 /NO with unsaturated fatty acids derivative may represent a convenient and straightforward route for the small scale preparation of nitrated lipid products of potential biological interest. Unsaturated fatty acids are nitrated endogenously to produce nitrated lipids. Recent studies have shown that these nitrated lipids have high chemical reactivity and profound biological implications. We report an efficient, enzymatic synthesis of nitrated derivatives of the oleic acid. The methyl oleate could react with NO and horseradish peroxidase (HRP)/H 2 O 2 /NO based nitrating systems to give various nitration products which could be isolated by silica gel column and TLC fractionation, respectively. As reacting directly with NO, the obtained products contain (E)-methyl 9-nitrooctadec-9-enoate ( 1) , (E)-methyl 10-nitrooctadec-9-enoate ( 2) , (E)-methyl 9-nitrooctadec-10-enoate ( 3) and (E)-methyl 10-nitrooctadec-8-enoate ( 4) , characterized by extensive IR, NMR and GC–MS analysis. Whereas the products of the reaction between the methyl oleate and NO with the presence of HRP/H 2 O 2 were mainly composed of (E)-methyl 9-nitrooctadec-9-enoate and (E)-methyl 10-nitrooctadec-9-enoate. The improving selectivity of the products is attributed to the HRP catalysis system.