This blog lists that research that I have conducted as a part of the Bradley Research Group in the Chemistry Department at Drexel University and documents significant events in my young career as a scientist. I am participating in the Open Notebook Science Challenge for which I am performing experiments to measure the solubility of certain compounds (ex. carboxylic acids) in organic solvents. One of the goals of this challenge is to promote transparency in the scientific process. Every reported scientific finding is only as reliable or as meaningful as the steps incorporated to obtain that finding. This challenge requires that a detailed log of all steps completed in the experiment be recorded and posted in order that anyone attempting to repeat the experiment or desiring to better understand the meaning of the reported result is able to observe exactly what steps were carried out. From these solubility experiments, mathematical models are built to predict solubility. These models are used to choose recrystallization solvents and plan synthesis reactions. The products of these reactions are investigated as potential treatments for various diseases such as cancer and malaria.

Tuesday, September 11, 2012

STAR Scholar Research

This past summer I participated in the 10-week research program known as the STAR Scholars Program.  I was able to work approximately 40 hours a week dedicated to scientific research.  I will summarize the research I conducted.

The solubility of trans-dibenzalacetone was measured at 25°C using NMR in the solvents benzene, THF, cyclohexane, cyclohexanone, and toluene (EXP308), the solvents methanol, cyclohexanol and acetonitrile (EXP311), the solvents diethyl ether and acetone (EXP313), and the solvents n-hexane, cyclohexane, methanol, 2-propanol and a ethanol/water(50:50)vol mixture (EXP324).  All of the solubility measurements can be found here (may take a moment to load).  The ADmodel003 provides a predicted solubility measurement using no experimental values (uses predicted Abraham Descriptors for the compound).  The ADmeasured model provides predicted solubility measurements using measured Abraham Descriptors for the compound generated from at least five experimentally measured solubilities.  The experimental lists the available experimental measurements.  The model003 is the most useful, because it removes the need for any experimental values, but this model is still being investigated for accuracy.

These solubility values for trans-dibenzalacetone were acquired as a part of the Recrystallization Project.  Through this project, a smartphone app was created for choosing recrystallization solvents, obtaining melting point data, obtaining LogP data and obtaining the MSDS for compounds.  Here is an image of the home page of the app:


This app uses the solubility data obtained at room temperature (25°C) to predict what the recrystallization yield for a compound will be depending on the solvent.  If experimental solubility measurements are not available, a predicted solubility is used and this allows for a solvent to be chosen for the recrystallization of a compound never synthesized before.

In addition to this solubility work, a library of compounds that could be synthesized through the dibenzalacetone procedure, but using different aldehydes was created.  Dibenzalacetone is synthesized using benzaldehyde and acetone.
By changing the aldehyde used (as long as there is a hydrogen on the alpha carbon of the aldehyde), the product can be altered.  A library of compounds that could be synthesized was run against the docking site of Taxol.  Taxol is a drug used in the treatment of cancer.  The top hit is a compound synthesized using the aldehyde phenanthrene-9-carboxaldehyde. 
In UCEXP286, this product was synthesized and results are pending regarding the activity of the compound in the docking site of Taxol.  Below is a picture of the yellow product:



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