Week 4: July 22nd – July 26th

I was working on 2-tert-Butyl-1,4-benzoquinone and 2-phenol-1,4-benzoquinone for the previous week and managed to isolate some single spots using column chromatography, and then I did NMR spectrum on these isolated molecules. NMR is the abbreviation for nuclear magnetic resonance, and it is a way of obtaining information about the molecule’s structural information. The NMR spectrum showed that both molecules undergo the cyclization reaction. For 2-tert-Butyl-1,4-benzoquinone product, the spectrum shows that it is pretty pure with traces of solvent; however, 2-phenol-1,4-benzoquinone cyclization product is a mixture of isomers. Isomers are compounds with the same chemical formula but different structures. Because of the close similarity of the two isomers, it is difficult to separate them well. I have tried several solvent systems for the purpose of separate, but none of them work. I may keep trying to look for a method to separate the compound. Hopefully, it will work the next time. It is the nature of scientific research that you will face a lot of surprises and failures. Maybe the isomers won’t be able to be isolated; maybe a solvent system will do the job. I will stay optimistic and keep all the trials. Starting from last week, I also started working on the reaction mixture from 2-chloro-1,4-benzoquinone as starting material. It was a crude product from the reaction, meaning it hadn’t been worked up yet. I extracted the reaction mixture with multiple solvents to get rid of the solvent which we used for the reaction. Other than that, it was all of the same experimental procedure of column chromatography, TLC and NMR. It turns out that 2-chloro-1,4-benzoquinone also undergoes the cyclization reaction. It was pretty amazing because halogens usually make things a little bit strange, but the result was exciting. However, after being identified using NMR, the product is a mixture of similar isomers.

Week 3: July 15th – July 19th

At the end of my last blog post, I mentioned working on 2-tert-Butyl-1,4-benzoquinone and 2-phenol-1,4-benzoquinone. The lab techniques I employed working with molecules is called column chromatography and thin-layer chromatography (TLC). We had firstly run an organic chemistry reaction, and we got a reaction mixture. Inside the reaction mixture will be different products or unreacted starting materials mixing together. One of our purposes is to identify the identity of the molecule via some instrumental analysis (more details will be coming in the following posts.) Therefore, it is important for us to separate a single pure molecule from the reaction mixture. Column Chromatography is a common way to separate compounds from a mixture. As different molecules have a different affinity to the column due to varied polarity, they will move through the column at a different rate. We let the reaction mixture flows through the column, flush the column with a suitable solvent system and collect the product in fractions into vales. In order to tell whether the fraction only has a single molecule or not, TLC is needed to do the job. A capillary tube will be utilized to get a tiny amount of the liquid in each fraction vials, and the liquid will be spotted onto the TLC plate. An eluent solution will be used to let the spotted liquid to travel up the plate. The resulting plate will be observed under ultraviolet light because our produce is UV-active, so each dot will represent a molecule. Those fractions with only one dot will be combined for further instrumental analysis to identify their chemical structure. Stay tuned for next week for the instrumental analysis part.

Week 2: July 8th – 12th

I just finished my study abroad program in Germany and went back to William and Mary. I was pretty excited to start my summer research project. The research in our lab focuses on a group of organic molecules called quinone, specifically, 1,4-benzoquinone and its derivatives. Quinones are cyclic organic compounds which have a conjugated dione structure. Quinones are frequently found in natural products in living organisms. A natural product is a chemical compound that is produced by life. In this research project, we previously found that methyl-p-benzoquinone undergoes diels-alder and oxidizing aromatization reaction with prenyl-bromide to produce 2,7-Dimethyl-1,4-naphthoquinone, which is commonly known as chimaphillin. Chimaphillin is a natural product found in pyrola and is found to have anticancer activities. Since in the natural world, the living organism is unable to produce enough amount of the molecule, it is important to be able to synthesis these molecules in the lab with accessible starting materials.

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Week 1: May 6th – 10th

My summer research has a relatively weird time frame. I started my research one week right after the final, paused for 1.5 months because of my study abroad program and continued the rest six weeks starting from early July.

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