Alisha Esmail

Mentor: Dr. Sharon Burgmayer

The transition metal molybdenum plays a crucial role in the active site of more than 40 enzymes that are necessary to sustain life in many species. When Molybdenum is coordinated by a special ligand, it forms the Molybdenum cofactor (Moco). The Moco is known to facilitate redox reactions and also participate in carbon, nitrogen, oxygen and sulfur cycles.  Moco consists of a single molybdenum center coupled to a tricyclic pyranopterin via a dithiolene.

The most immediate goal of this research project will be to replace the depleted supply of 6-chloro-pterin (3), which is the starting material required for making the 2-pivaloyl-6-chloro-pterin (4) that is then used to make one of the pterinyl alkyne precursors called BMOPP (5). In this process I will experiment several techniques such as using the schlenk line, vacuum filtration, column chromatography, FT-IR and 1H NMR.

Structure Figure 1

Figure 1: Synthesis series of BMOPP, a pterinyl alkyne precursor.

Then, I intend to transition ahead into synthesizing the entire Moco model, which is comprised of two parts: (1) the Molybdenum metal bound to the dithiolene ligand, and (2) the pterin moiety. In addition to that, I also want to synthesize and study the different analogs of the molybdenum cofactor complex, which include BMOPP, POPP, MBMOPP, BOPP, PEOPP and BMOP-TMS.  The variations of the steric and electronic nature of the pyrazole substituents could further enable understanding the reactivity and synthesis of the complex.