Thiol-induced nitric oxide donation mechanisms in substituted dinitrobenzofuroxans

- Dinitrofuroxans with π-donor substituents in the position 7 are prone to N-oxidic tautomerism.
- Furoxans easier donate NO in the 3-N-oxide form than in 1-N-oxide form.
- 7-Substituted furoxans are not affected by the Boulton-Katritzky reaction.
- 7-Substituted dinitrofuroxans exist in two atropisomeric forms.
- NO donation is easier in anti atropisomer.

The goal of present work is the quantum chemical study of NO donation mechanism in dinitrobenzofuroxan aryl derivative. Mechanisms of its structural non-rigidity (1,3-N-oxidic and Boulton-Katritzky rearrangements) and minimum energy pathways of NO donation under the action of sulfanyl radical SH· were considered in details. DFT calculations were performed using B3LYP and UB3LYP functionals in the 6-311++G(d,p) basis set. Obtained results showed that a high experimentally proven NO-donor activity of dinitrobenzofuroxan aryl derivative is connected with its existence in the form of mixture of 1-N-oxide and 3-N-oxide, where the 3-N-oxide is more reactive towards SH·. The thiol-induced low-barrier mechanism of NO-donation is a result of para-aminophenyl substituent availability in position 7 of dinitrobenzofuroxan.

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