Synthesis of New Lipophilic Rosin-based Methanofullerenes from Bromoand Chloromethylketones N-substituted Proteinogenic Amino Acids

Title:Synthesis of New Lipophilic Rosin-based Methanofullerenes from Bromoand Chloromethylketones N-substituted Proteinogenic Amino Acids

Volume: 14 Issue: 8

Author(s): Ilshat M. Sakhautdinov*, Rauilya N. Malikova, Oksana V. Akchurina, Svetlana F. Petrova and Marat S. Yunusov

Affiliation:

• Ufa Institute of Chemistry, Russian Academy of Sciences, Prospect Oktyabrya, 71, 450054, Ufa,Russian Federation

Keywords: [2+1]-cycloaddition, the Arndt-Eistert reaction, methyl maleopimarate, methanofullerenes, the Bingel reaction, amino acids.

Abstract: Background: Synthesis of lipophilic mitochondria-targeted antioxidants is a topical problem of modern biochemistry. The so-called "radical sponges" effect is a very high ability of fullerene C₆₀ and its derivatives to catch free radicals. The experiments showed that the fullerene derivatives increase resistance of animals towards oxidative stress and prevent passing of neurodegenerative processes.

Objective: Synthesis of lipophilic fullerene C₆₀ conjugates based on maleopimaric acid derived from resin.

Methods: Synthesis of new diterpene containing fullerene C₆₀ conjugates based on the bromo- and chloromethylketones by primary functionalization of the fullerene core by the Bingel cyclopropanation reaction was shown. Bromo- and chloromethylketones were obtained from methyl maleopimarateproteinogenic amino acids condensation products by the Arndt-Eistert reaction.

Results: Diazoketones and chloromethylketones were received from carboxylic acids and corresponding chlorides under Arndt-Eistert reaction conditions. Chloromethylketones formed due to a Nierenstein side reaction. The IR spectra of diazo compounds 2a-e contained a strong absorption band for the diazo group at 2103-2115 cm^–1. The reaction of diazoketones with HBr produced bromomethylketones in excellent yield. Bromo- and chloromethylketones were reacted with fullerene C₆₀ in the presence of 1,8-diazabicyclo(5.4.0)undec-7-ene (DBU) in toluene to give diterpene containing fullerene conjugates. Fullerene conjugates formed 6% oil solutions in different sunflower oils. The structures of all compounds obtained were proved using 2D NMR HSQC, HMBC, COSY, NOESY experiments.

Conclusion: Rosin-based methanofullerenes were synthesized for the first time under Bingel conditions by [2+1]-cyclopropanation of the chloro- and bromomethylketones to fullerene C₆₀ in the presence of DBU. In our case chloromethylketones gave better yields in the Bingel reaction than bromomethylketones. The obtained diterpene containing fullerene conjugates have the ability to dissolve in sunflower oils.

Cite this article as:

Sakhautdinov M. Ilshat *, Malikova N. Rauilya , Akchurina V. Oksana , Petrova F. Svetlana and Yunusov S. Marat , Synthesis of New Lipophilic Rosin-based Methanofullerenes from Bromoand Chloromethylketones N-substituted Proteinogenic Amino Acids, Letters in Organic Chemistry 2017; 14 (8) . https://dx.doi.org/10.2174/1570178614666170614091621

DOI https://dx.doi.org/10.2174/1570178614666170614091621	Print ISSN 1570-1786
Publisher Name Bentham Science Publisher	Online ISSN 1875-6255