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Photo-Dealkylation
of 1,4-Naphthoquinone Derivatives by Irradiation
Here we study a novel dealkylation
reaction of 2-alkylamino-3-bromo-1,4-naphthoquinone and its analogs
under irradiation. Due to the fact that 1,4-naphthoquinone derivatives
play an important role in our biological system, understanding how
irradiation affects certain derivatives of 1,4-naphthoquinone is
imperative. For instance, 2-isopropylamino-3-bromo-1,4-naphthoquinone is
known to dealkylate under irradiation, yielding
2-amino-3-bromo-1,4-naphthoquinone. On the other hand,
2-isopropylamino-1,4-naphthoquinone has no reaction when irradiated. As
to examine why this reaction occurs, we are currently focusing on three
aspects: the nature of alkylamino substituents at the 2-position, the
role of substituents at the 3-position, and the effect of reaction
environments. Furthermore, the fate of the dealkylated moiety must be
identified to disclose the reaction mechanism. One product was
characterized as cyclohexanone during the irradiation of
2-bromo-3-cyclohexylamine-1,4-naphthoquinone. In regards to varying
alkyl-amino groups attached at the 2-position, a secondary alkyl group
was found to be favored for dealkylation.Similarly, substituents at the
3-position that are viable for dealkylation to occur include: bromine,
methoxy, methyl, and chlorine. This suggests that the size of the
3-substituent is pertinent for dealkylation. Lastly, we suspect that
oxygen is necessary for this photo-dealkylation to take place. Through
examining various factors, we plan to be able to determine the
fundamental chemical necessities needed for this unique photo-dealkylation
reaction to occur. Support provided by: Fletcher Jones Research in Chemistry/Biochemistry Fellowship |
