Shadia Bel Hamdounia
Mentor: Dr. Sharon Burgmayer
The molybdenum cofactor (Moco) is a critical component of oxygen transfer enzymes, which catalyze a variety of biological reactions that are crucial to the survival of all organisms. Moco has been a major focus of Dr. Sharon Burgmayer’s research for nearly two decades particularly due to the unusual redox activity of the Mo center and its molybdopterin ligand. Since Moco is unstable outside of its host environment, any spectroscopic determination of physical and electronic properties requires the synthesis of a model compound.
Figure 1. The general structure of Moco:
The synthesis of Moco is comprised of eight reactions, requiring about twelve days to complete. This summer, I will be working under the guidance of Mica Grantham, to master the final three reactions. Using the 6-chloropterin that Candi Greeman synthesizes over the summer, I will be synthesize the pterin as follows:
Figure 2. Reaction 6: Pivalation
The product will then be used in a recently adopted synthetic pathway to create one of several pterins: acetyl, phenyl, and difluoropheynyl, ethynyl pivulated pterin. (i.e. AEP, PEPP, and diFPEPP, respectively). Finally, AEP and diFPePP will be reacted with Mo so that both Moco models can be studied, as shown:
Figure 3. Forming the Tp*ModiFPEPP Moco Model
Goals for this summer are to master the techniques used for the reaction sequence, to continue to build up stockpiles of intermediates, and to spectroscopically probe Moco’s electronic properties.