Tyrosine

This week for Organic Chemistry, we were assigned an amino acid, and given a list of items to research and report on. I was assigned Tyrosine (2-Amino-3-(4-hydroxyphenyl)propanoic acid), which is a non-essential amino acid with a polar side chain.
The abbreviated names for Tyrosine are Tyr or Y. Tyrosine is found in a polypeptide called Peptide YY, which "is a short (36-amino acid) protein released by cells in the ileum and colon in response to feeding. In humans it appears to reduce appetite." The pKa values are COOH - 2.20, NH3+ - 9.11, and side chain (phenol) 10.07. The isoelectric point (pH) is 5.66. An interesting fact about Tyrosine is the word comes from the the Greek tyri, which means cheese (it was first discovered in cheese). Tyrosine can be found in many high protein food products such as soy products, chicken, turkey, fish, peanuts, almonds, avocados, milk, cheese, yogurt, cottage cheese, lima beans, pumpkin seeds, and sesame seeds. In the medical field, research has shown that Tyrosine can increase plasma neurotransmitter levels (particularly dopamine and norepinephrine). I really enjoyed doing this blog and found the research very interesting. There was a lot of info on this amino acid and a short paper could be written on the subject.


-The High School Chemist


Sources
- http://en.wikipedia.org/wiki/Peptide_YY
- http://en.wikipedia.org/wiki/Tyrosine
- http://www.chemie.fu-berlin.de/chemistry/bio/aminoacid/tyrosin_en.html

Electrophilic Aromatic Substitution

This week in organic chemistry, we were assigned to find a journal with at least one electrophilic aromatic substitution (EAS) step and talk about the step specifically. After much searching, I was able to find an article that did not require me to purchase it. The article is titled "Selective Nitration of Aromatic Compounds with Bismuth Subnitrate and Thionyl Chloride" and is written by Hussni A. Muathen. In part of the article, Muathen talks of how "polycyclic aromatic hydrocarbons can be efficiently mononitrated in good yields. Biphenylene, in particular, afforded 2- nitrobiphenylene as the only product in high yield." The image of this reaction would not let me save it or copy it, so if you would like to view the reaction, you can go to the source below. This nitration is performed very similarly to the nitrations in the book. The only difference between the two is the compound used to make the electrophile (NO2+) in the article is SOCl4 and the one used in the book is H2SO4. These two reagents achieve the same goal. Anyway I found this to be an interesting article and I'm glad I was able to share it. =)

-The High School Chemist

Source
http://www.mdpi.com/1420-3049/8/7/593/pdf