Final Organic Blog

Our final blog assignment for Organic Chemistry was to go to Christina White’s (U. Illinois) webpage and find a publication to read and comment on. After a little browsing, I found an article, titled Synthesis of Complex Allylic Esters via C-H Oxidation vs C-C Bond Formation, that interested me. In this publication, there are many many reactions and compounds, but there were two things that caught my eye when looking for something related to our class. (Sorry I don't have any illustartions, I couldn't copy or save the pictures. I don't know if it was the article, my computer, or me, but if you would like to see them, follow the link below.) The first was the table on page 2, that shows linear allylic oxidation. The general scheme shows a linear alkene reacted with a carboxylic acid to form an ester. The article takes the specific esters in the table and explains how to prepare each and talks about their specific properties. The other thing that I found interesting were the schemes on page 7 and 8. Both schemes show two paths to arrive to the same molecule, which is something I have always found neat about organic chemistry. The scheme on 7 has one step that uses a Grignard reagent, something we learned about not too long ago, and the scheme on 8 uses a Grubbs catalyst, something we will have learned about by the time anyone reads this. Those were the two steps of all the reactions that stood out to me, but the publication was full of reactions and catalysts that we have learned about in organic chemistry.


Signing off one last time
-The High School Chemist


Source
Vermeulen, Nicolass A. et al. Synthesis of Complex Allylic Esters via C-H Oxidation vs C-C Bond Formation. JACS, 2010, 132, 11323. http://www.scs.illinois.edu/white/index.php?p=publications (accessed May 1, 2011).

Potential Test Question for Exam 5

This week (second to last... whoot whoot) in organic chemistry, we were assigned to come up with a potential question for our upcoming exam. My question would be... Draw the reactants that would undergo a Claisen Reaction to give the following product.

The answer would be

(For anyone who might be impressed, I had to draw these backward so they would come out straight when I took the picture)
-The High School Chemist

Dr. Steven R. Myers Seminar

Last week, I attended a seminar given by Dr. Steven Myers, from the University of Louisville School of Medicine Department of Pharmacology and Toxicology, titled "Tobacco Smoking During Pregnancy: Biomarkers of Exposure and Relationship to Genetics." I really enjoyed this seminar because I plan on going into the medical field and find subjects such as this fascinating, and because he gave the seminar on an undergraduate level, making it easy to follow. He began his seminar by telling of all the different possible side effects of smoking while pregnant: higher rates of miscarriage, still born babies, premature birth, low birthweight, SIDS, lower I.Q., asthma, and many others. I did feel that this part of the seminar was a little slow because of repetition; he had the same side effects on multiple slides. He continued the seminar with smoking related facts: smoking is the leading cause of avoidable cancers, smoking contributes to cardiovascular, cerebrovascular, respiratory, and pediatric diseases, cigarette smoke gives off 4,000 different chemicals (e.g. 4-aminobiphenyl),

and the first 6-8 weeks of pregnancy is when the baby is most susceptible to cigarette smoke. Dr. Myers then got into what biomarkers are and what their use is to determine the effects of smoking on unborn babies. He defined a biomarker as a molecular, biochemical, or cellular alteration that can be measured (e.g. biological fluids). The questions that you have to ask when choosing a biomarker are what is the relationship between the biomarker and the disease, how long does it take the biomarker to pick up the disease, can the biomarker be obtained unobtrusively, is the biomarker easy to process, and how do genetics and race affect the biomarker? Some of the most effective biomarkers are amniotic fluid, for the first trimester, and blood. I thoroughly enjoyed Dr. Myers' seminar and have no negative comments other that it started off slow (not really a big deal door a good seminar).

-The High School Chemist

Source
http://en.wikipedia.org/wiki/File:4-aminobiphenyl_structure.svg

Hell-Volhard-Zelinsky Halogenation Reaction

This week in Organic Chemistry, we were assigned to find a piece of literature that has a Hell-Volhard-Zelinsky (HVZ) halogenation and talk about that specific reaction. I found this blog to be the most difficult one yet due to not being able to access most chemistry journal articles without paying a large fee. HVZ is when a carboxylic acid is treated with a tri-halogenated P (PCl3, PBr3, ect.), and this reaction halogenates the alpha carbon of the carboxylic acid. HVZ begins by replacing the OH group of the C.A. with a halogen. Then another halogen is added to the alpha carbon of the C.A. Finally, the original halogen is replaced with an OH group, thus making the molecule a C.A. again. The picture below is the mechanism for an HVZ reaction.

The specific HVZ that I found reacts cyclohexanecarboxylic acid with PCl3 to yield
1-chlorocyclohexanecarboxylic acid. The OH group of the C.A. is replaced with Cl, followed by chlorination of the alpha carbon. Then the molecule undergoes hydrolysis to form the final product. The reactant and product can be seen in example 1 below.

-The High School Chemist


































Sources
http://www.springerlink.com/content/t2ur113r36720270/
http://en.wikipedia.org/wiki/Hell-Volhard-Zelinsky_halogenation

Isobutyl propionate

Our assignment for Organic this week was to research and report on an ester that was assigned to us. I had isobutyl propionate (for the sake of length, I will abbreviate it IP), on which I was surprised to find a lot of information. IP has a molecular formula C7H14O2 and a molecular weight of 130.185. This ester is a colorless clear liquid, has a specific gravity of 0.86500 to 0.87100 at 25.00 °C, a melting point of -71.00 to  -70.00 °C at 760.00 mm Hg, and a boiling point of 137.00 to 138.00 °C. at 760.00 mm Hg. I expected to find this general information, but I did not expect to find information such as the odor description at 100% being, and I quote, "fruity green ether sweet tutti frutti banana" and the taste description at 10.0 ppm being "sweet, fruity, banana, tutti frutti, with rummy nuances." After further reading, it made sense when I found that IP is used as a flavor and fragrance agent. Propanoic acid and 2-methylpropanol would be the carboxylic acid and alcohol pair from which this ester is derived. IP could be reacted with NH3 to form the primary amide propanamide. That was a lot of information and I hope you find it interesting. Here is a picture of IP if you are interested.

-The High School Chemist


Sources
http://www.thegoodscentscompany.com/data/rw1020241.html
http://www.caslab.com/Isobutyl_propionate_CAS_540-42-1/

Grignard reagent in synthetic step

This week in organic chemistry, we were assigned to search for a reaction that involves the use of an organolithium, organocuprate, or Grignard reagent in at least one synthetic step. I searched for a Grignard step, and found one in the synthesis of bis[3,5-bis(trifluoromethyl)phenyl]phosphine oxide. As seen in the diagram below, i-PrMgCl and THF are added to 3,5-bis(trifluoromethyl)bromobenzene. This inserts an Mg between the benzene ring and the Br (this first step of a Grignard reagent reaction). Then, (EtO)2POH and more THF are added to the middle reactant, linking two of the substituted benzene rings together through phosphorous, and the final product ([3,5-bis(trifluoromethyl)phenyl]phosphine oxide) is made. The CAS number for this compound is 15979-14-3, the molecular weight is 474.18, and the molecular formula is C16H7F12OP. I included the second part of this synthesis because DIBAL-H (a reagent that we studied along with the Grignard reagent) is used in the reduction of the phosphorous, thus removing the double bonded oxygen.

-The High School Chemist

Sources
-http://orgsyn.org/orgsyn/default.asp?formgroup=basenpe_form_group&dataaction=db&dbname=orgsyn
-http://www.guidechem.com/cas-159/15979-14-3.html

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