Oxidative reactions of C-H bonds in nitrogenous compounds in the presence of a iron-ferro catalyst

Author(s)

Kelita Angelo de Paula

• Document type: Master's Dissertation
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Instituto de Química
• Defense date: 2023-05-25

Examining board members

Emilio Carlos de Lucca Júnior; Júlio Cezar Pastre; Marco Antonio Barbosa Ferreira

• Advisor: Emilio Carlos de Lucca Júnior

Abstract

The diversity of organic molecules, drugs and natural products is still mostly obtained through classical methods of organic synthesis, with the manipulation of reactive functional groups (carbonyls, amines, halogenated groups). However, in recent decades, studies of catalytic reactions involving selective oxidation of inactive C-H bonds and with good yields have proven to be a complementary and interesting alternative for obtaining products. In this work, the oxidation reactions of C-H bonds in nitrogenous compounds were carried out at room temperature in the presence of catalyst A, synthesized in the research group itself, H2O2 as a terminal oxidant and carboxylic acid as an additive. Initially, catalytic optimization was carried out by varying the carboxylic acids and solvents. The eight carboxylic acids studied were acetic acid, propanoic acid, isobutyric acid, pivalic acid, cyclopropanoic acid, ethylhexanoic acid, chloroacetic acid and benzoic acid). The solvents were acetonitrile (MeCN), 2,2,2-trifluoroethanol (TFE), 1,1,1,3,3,3-hexafluoroisopropanol (HFIP), tert-amyl alcohol (TAA), eucalyptol and Gamma-valerolactone (GVL). The reaction condition that provided the best yields was in the presence of a mixture of solvents MeCN:TFE (4:1) and isobutyric acid. The studies with the nitrogenous compounds proposed in the scope produced oxidized products with a yield between 30 and 48%. However, the formation of methyl ketones as by-products of the reactions in approximately 10% yield, an unexpected result for this catalytic system, instigated new guidelines for this project. Compounds containing olefin, epoxide, diol and hydroxy-acid have been proposed as possible intermediates leading to the formation of methyl ketone. Oxidative reactions with these compounds formed the product of interest in varying yields. The highest yields were found with diol (88%) and hydroxy-acid (70%), a result considered unprecedented for iron chemistry so far and which probably indicates that they are important intermediates for the formation of methyl ketone (AU)

• FAPESP's process: 20/11568-1 - Development of a catalytic system compatible with olefins and aromatic systems for oxidation of C-H bonds
• Grantee: Kelita Angelo de Paula
• Support Opportunities: Scholarships in Brazil - Master