Summer Undergraduate Research Mentored Experience

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Dr. Katja Michael

Department of Chemistry

Synthesis of new photoreactive compounds: 1-acyl-2,2-dimethyl-5-bromo-7-nitroindolines

Preferred major field of study or minimum required skills

chemistry major, basic organic chemistry skills in theory and practice

Scholarly significance/intellectual merit

N-acyl-7-nitroindolines are photoreactive compounds that are capable of an acyl transfer to a variety of nucleophiles, such as amines, aminals, hydrazine, alcohols, and thiols (see three publications from our research group: Kaneshiro & Michael, Angew. Chem. Int. Ed. 2006, 45, 1077; Hogenauer et al., Org. Biomol. Chem. 2007, 5, 759; and Pardo et al., ChemBioChem 2015, 16, 1884). These photochemical acylation reactions produce amides, oxoesters, thioesters, and hydrazides under mild, neutral conditions, and are therefore very useful synthetic tool. The photochemical reaction is typically carried out in inert organic solvents. In water, a different photolysis mechanism leading to carboxylic acids has been discovered (Morrison et al., Photochem. Photobiol. Sci. 2002, 1, 960). It would be a breakthrough in the field of synthetic photochemistry if the acyl transfer photochemistry could tolerate a wide variety of solvents including aprotic and protic solvents, because it would open doors to the mild, photochemical synthesis of a number of sensitive biomolecules that are only soluble in polar solvents such as water and alcohols. We believe that the installation of two methyl groups at position 2 of the nitroindoline ring changes its photochemical properties and will result in a superior photoreactive compound that tolerates a wide variety of solvents.

Research question(s)

  • Are 1-acyl-2,2-dimethyl-5-bromo-7-nitroindolines capable of the same photochemistry as the non-methylated parent compound? (Our preliminary data suggest that the answer is yes, but more experiments are required.)
  • Are the yields of the photoacylation comparable or even higher?
  • Does the photochemistry of 1-acyl-2,2-dimethyl-5-bromo-7-nitroindolines tolerate protic solvents?
  • Does the photochemistry of 1-acyl-2,2-dimethyl-5-bromo-7-nitroindolines produce any undesired carboxylic acid byproducts?  

Methods/techniques/instruments to be learned/utilized

The undergraduate student will receive training in the laboratory techniques required for the synthesis of small heterocyclic molecules, in synthetic photochemistry, in compound purification by chromatography, and in compound analysis by mass spectrometry, and 1H and 13C nuclear magnetic resonance spectroscopy.