Senior Katelyn Bercaw syn­the­sized nine quinoline com­pounds as a part of her syn­thetic chem­istry research. Katelyn Bercaw | Courtesy

Syn­the­sizing a group of mol­e­cules and testing their bio­logical appli­ca­tions can be dif­ficult to accom­plish in a six-week span, according to senior bio­chem­istry major Katelyn Bercaw. To help future researchers, Bercaw spent part of her summer syn­the­sizing several types of quino­lines, a group of mol­e­cules known to have med­i­cinal appli­ca­tions.

The quinoline library she con­structed with Assistant Pro­fessor of Chem­istry Courtney Meyet, her research adviser, will allow future research projects to focus on testing the quino­lines’ effects on bac­terial growth.

“The reason we were syn­the­sizing them in the lab was twofold: Dr. Meyet worked on these during graduate school, so she knows about them and how to syn­thesize them, and also because of their med­i­cinal appli­ca­tions,” Bercaw said.

Her project was a con­tin­u­ation of pre­vious research projects involving quino­lines. Last year, Stevan Lukich ’17 syn­the­sized several quino­lines and then worked with biology department chair Frank Steiner and applied them to bac­teria.

“He found that they have the ability to kill MRSA, methi­cillin-resistant bac­teria, which is cool because we’re always looking for ways to kill antibiotic-resistant bac­teria,” Bercaw said.

Lukich and Naomi Vir­nelson ’16 both worked with quino­lines to see which spe­cific quinoline com­pounds would have the most impact against bac­teria.

“Naomi had actually found the com­pound that had the most activity,” Meyet said. “Stevan also syn­the­sized that and found it to be the case as well. What we were trying to do was to take that quinoline and syn­thesize quino­lines like it that could increase their activity.”

Quinoline mol­e­cules consist of two con­nected ring struc­tures, and the group of quino­lines Bercaw worked to syn­thesize also have addi­tional com­po­nents that branch off from certain parts of the ring struc­tures.

Within the quino­lines’ ring struc­tures, alter­nating single and double bonds con­tribute to the mol­e­cules’ antibac­terial prop­erties, Bercaw said. The posi­tions of the single and double bonds cause the quinoline’s elec­trons to become excited when exposed to ultra­violet light, and the energy they release after exposure to ultra­violet light allows them to kill bac­terial cells.

To make these spe­cific quino­lines, Bercaw used a method called one-pot syn­thesis, a system Meyet worked with while still in graduate school.

“She used a method that I had pre­vi­ously pub­lished on, so I was con­fident that the method would work very well,” Meyet said. “There were some com­pounds that she was syn­the­sizing that I don’t believe had been tried in that com­bi­nation.”

The one-pot syn­thesis involves adding the chemical pre­cursors for each quinoline — in this case, an amine, aldehyde, and alkyne — to a single test tube. Under certain con­di­tions, the mol­e­cules will react to form a quinoline with spe­cific groups attached to the quinoline ring.

Once the reaction occurs, Bercaw used several tech­niques, including column chro­matog­raphy, to sep­arate the quinoline mol­e­cules from the other com­pounds present in the test tube.

“It’s a fairly simple process,” Bercaw said. “Getting the column to run is probably the most chal­lenging step because you have to get a feel for how the dif­ferent mate­rials sep­arate.”

Bercaw said she was able to suc­cess­fully make nine dif­ferent quino­lines for future researchers to use in their own projects. She ini­tially struggled to isolate pure quino­lines, and found that other unwanted com­pounds were mixed in with her product. Meyet said they were able to identify the problem about halfway through the project: a sta­bi­lizing com­pound that was mixed in with one of the chem­icals they used in the syn­thesis.

“At least we have that issue worked out, so when it’s time for others to go and syn­thesize, we hope­fully won’t run into that same issue,” Meyet said.

Junior Rosemary Pynes said she will be con­tinuing Bercaw’s work in some capacity next summer, either by syn­the­sizing addi­tional quino­lines using the same method as Bercaw or by testing the quino­lines Bercaw syn­the­sized to see how they will impact bac­teria.

Bercaw, who plans to attend pharmacy school next year, said she enjoyed working on the project this past summer.

“It was fun to work with Dr. Meyet and just be ded­i­cated to one thing in a way that we aren’t able to when we’re doing labs for classes,” Bercaw said.