Synthesis and antioxidant properties of (dodecylsulfanyl)methyl quercetin derivatives

Mono-, bis-, and tris[(dodecylsulfanyl)methyl]-substituted quercetin derivatives were obtained by the reaction of quercetin with (N,N-diethylaminomethyl) dodecyl sulfide. These compounds under the conditions of AIBN-initiated oxidation of styrene (37 °C) terminated oxidation chains with a stoichiometric inhibition coefficients of 2.0±0.1 and rate constants of 5.1 · 105, 4.8 · 105, and 2.9 · 105 L mol-1 s-1, respectively. Based on the rate constants, the O-H bond energy values in the molecules of quercetin and its mono-, bis-, and tris- [(dodecylsulfanyl) methyl]-substituted derivatives were calculated and found to be equal to 334.4, 341.4, 341.7, and 344.7 kJ mol-1, respectively. It was established that the ability of the synthesized thio derivatives of quercetin to inhibit thermal autooxidation of lard (133 °C) is 1.3-2.7 times higher than that of the reference antioxidants (a-tocopherol, BHT, and BHA). According to the in silico assessment of acute toxicity for rats, the synthesized derivatives are low-toxic and non-toxic compounds.