Naslov
Revisited Mechanism of Reaction between a Model Lysine Amino Acid Side Chain and 4-Hydroxynonenal in Different Solvent Environments

Autori
Škulj, Sanja ; Vazdar, Katarina ; Margetić, Davor ; Vazdar, Mario

Izvornik
Journal of organic chemistry (0022-3263) 84 (2019), 2; 526-535

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
lysine ; 4-hydroxynonenal ; reaction mechanism ; quantum chemical calculations

Sažetak
We revisit the reaction mechanism of reaction between model lysine side chain and reactive aldehyde 4-hydroxynonenal in different solvents with increasing water content. We show by model organic reactions and qualitative spectrometric analysis that non-polar pyrrole adduct is dominantly formed in non-aqueous solvents dichloromethane and acetonitrile. On the other hand, in aqueous acetonitrile and neat water, other polar products are also isolated including Michael adducts, hemiacetal adducts and pyridinium salt adducts, at the same time decreasing the ratio of non-polar products vs polar products. The experiments are supported by detailed quantum chemical calculations of the reaction mechanism with different computational setups showing that the pyrrole adduct is the most thermodynamically stable product compared to Michael adducts and hemiacetal adducts and also indicating that water molecules released along the reaction pathway are catalyzing reaction steps involving proton transfer. Finally, we also identify the mechanism of the pyridinium salt adduct which is formed only in aqueous solutions.

Izvorni jezik
Engleski

Znanstvena područja
Kemija

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