Table of Contents
Introduction………………………………………………………………………..
Background…………………………………………………………………………
Previous Work……………………………………………………………………
Results and Discussion……………………………………………………………
Future Work………………………………………………………………………..…
Experimental Procedures………………………………………………………………
References………………………………………………………………………………
Introduction
Synthesis of molecules is very important in the development of natural products used in medicine today.1 However, there are many problems with the current synthesis method that conflict with many of the guidelines in the 12 Principles of Green Chemistry and are potentially hazardous.2 The proposed research plan includes the formation of a salt by allylation followed by the Aza-Claisen rearrangement which has shown success using benzothiazole. Ultimately, this research seeks to eliminate these costly, inefficient factors and create a more productive, safer plan to achieve the natural products used in medicine today.
Azoles are 5-membered ring heterocycles containing a nitrogen atom and at least one other non-carbon atom.
Azole derivatives are most frequently found in medicines that treat fungal infections. Some very common examples are fluconazole, miconazole, and ketoconazole which work by inhibiting cytochrome P450-dependent enzymes that are part of ergosterol synthesis within the cell membrane.3
Azoles can also be found in medication that treats AIDS, cancer, and acid reflux disease. The synthesis of azole derivatives is a key step in acquiring the compounds used in these drugs; and because azoles are widely used in today’s society, it is important to make this process as efficient as possible.
Over the past few decades, people in our society have become much more aware o...
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...ecent Advances in Carbon–Carbon Bond-Forming Reactions Involving Homoenolates Generated by NHC Catalysis. Nair, V.; Vellalath, S.; Babu, B. P. Chem. Soc. Rev. 2008, 37, 2691-2698.
11. Addition of N-Heterocyclic Carbenes to Imines: Phenoxide Assisted Deprotonation of an Imidazolium Moiety and Generation of Breslow Intermediates Derived from Imines. Simonovic, S.; Frison, J.-C.; Koyuncu, H.; Whitwood, A. C.; Douthwaite, R. E. Org. Lett. 2009, 11, 245-247.
12. Anti-Plasmodium Activity of Imidazolium and Triazolium Salts, Bioorganic and Medicinal Chemistry. Jason Z. Vlahakis, Carmen Lazar, Ian E. Crandall , Walter A. Szareka. 2010, 18, 6184-6196.
13. 13C NMR Spectroscopic Determination of Ligand Donor Strengths Using
N-Heterocyclic Carbene Complexes of Palladium(II). Han Vinh Huynh,* Yuan Han, Ramasamy Jothibasu, and Jie An Yang. 2009, 5395-5405.
This week’s lab was the third and final step in a multi-step synthesis reaction. The starting material of this week was benzil and 1,3- diphenylacetone was added along with a strong base, KOH, to form the product tetraphenylcyclopentadienone. The product was confirmed to be tetraphenylcyclopentadienone based of the color of the product, the IR spectrum, and the mechanism of the reaction. The product of the reaction was a dark purple/black color, which corresponds to literature colors of tetraphenylcyclopentadienone. The tetraphenylcyclopentadienone product was a deep purple/black because of its absorption of all light wavelengths. The conjugated aromatic rings in the product create a delocalized pi electron system and the electrons are excited
The goal of this lab is to exemplify a standard method for making alkyne groups in two main steps: adding bromine to alkene groups, and followed by heating the product with a strong base to eliminate H and Br from C. Then, in order to purify the product obtained, recrystallization method is used with ethanol and water. Lastly, the melting point and IR spectrum are used to determine the purity of diphenylacetylene.
We successfully achieved our goal of synthesizing benzhydrol, but we did not successfully reach the goals of the completion of the synthesis or purification of benzhydrol.
In addition to this, these compounds also display antagonist activity to calcium 23. For this reason, and for their associated pharmacological properties, a lot of interest and attention has been drawn to them in the recent years by researchers 22. A couple of methods have consequently been developed for the preparation of the octahydroquinazolinone derivatives 2. The most common of which include the Biginelli one pot reaction that involves urea/ thiourea, aromatic aldehydes and dimedone 24. Other methods include synthesis with the help of catalysts like concentrated sulfuric acid, Nafion-H, ionic liquid, and TMSCI 24. Synthesis in low ethanol could also be adopted but it is characterized with product yields that are between 19-69% and these are
By comparing the overall percent yields based upon pathway, the statistically superior pathway proved to be the Red pathway, which also happens to be the synthesis pathway I implemented. I determined that this was the best pathway based on the mean, median, and maximum overall percent yields of each pathway and are shown on Table 2. I hypothesize that this pathway was most successful because of the order of the reagents used, specifically that the nitration was the second step. I hypothesize that the addition of the nitro group to the benzoic acid was more successful than other reaction pathways because the attached carboxylic acid group is a moderate deactivator and meta director, more so than the attached ketone in the Blue pathway or the attached ester in the Green
Staudt, Maureen, and Michael Stranz, eds. General Chemistry for Engineering and Science II. Mason,Ohio: Cengage Learning, 2012. Print.
.This experiment was performed to determine the structure of alkyl-halides formed as a result of substitution reactions, and whether the reaction used an SN1 or SN2 mechanism. The structure of the starting alcohol determined the mechanistic pathway of the substitution reaction. Reaction 1 involved the substitution of a primary alcohol which produced one primary alkyl-halide via SN2 reaction. Reactions 2 and 3 began with a secondary alcohol, forming two products as the result of direct substitution and/or a hydride shift, via SN1 reaction. Reaction 2 formed two secondary alkyl-halides, and Reaction 3 formed one secondary and one tertiary alkyl-halide.
Traditionally cyanide was used as a catalyst in this reaction since Von Liebig first discovered it in his research with almond oil. However, cyanide is very poisonous and harmful to health. More recently it was discovered that Vitamin B1, a coenzyme by the name of thiamine hydrochloride may be used to catalyze the benzoin condensation, which is preferable to using cyanide. This experiment will test whether thiamine can effectively catalyze the reaction (2).
W. A. Konig, D. H. Hochmuth, D. Joulain, Library of MassFinder 2.1 University of Hamburg, Institute of Organic Chemistry, Hamburg 2001
The purpose of conducting this experiment was to synthesise and characterise for the preparation of benzocaine via a fishcer esterification reaction by the means of amino benzoic acid alongside ethanol. The product was also precipitated from a solution in order to gain a pH of 8.The secondary aim was to esterify the reaction in an equilibrium reaction catalysed via the addition of acid shown below:
For the reaction, thiamine was used in our reaction in the formation of the product. Thiamine attacks the carbonyl carbon of an aldehyde in the same way a cyanide ion does. By removing a relatively acidic proton on the five-membered thiazolium ring of thiamine by a base, carbanion that is nucleophilic is produce and can attack the carbonyl. Moreover, thiamine hydrochloride was chosen as the reagent over cyanide because of dangers involved in the use of cyanide, which is a lethal poison that can kill with little warning. Thiamine HCL has been shown to be an efficient and safer catalyst for the condensation of benzaldehyde, which could qualify this reaction as a green chemistry reaction. This reaction turned the aldehyde into a hydroxy ketone by adding a benzyl alcohol, forming a new C-C bond. The Cannizzaro reaction did not occur in this reaction, as benzoic acid or benzyl alcohol would have formed instead of
In the reaction conducted in this experiment, three mechanisms were possible: Anti Addition, Syn Addition, and Anti and Syn Addition. Addition mechanisms involve removing a double bond between two adjacent carbons and adding one nucleophile (bromine in this case) to each of the carbons. Anti Addition results in a product in which the two bromines are anti-periplanar (or trans) to one another. Syn Addition results in a product in which the two bromines are syn-periplanar (or cis) to one another. Anti and
Plontke, R. (2003, March 13). Chemnitz UT. TU Chemnitz: - Technische Universität Chemnitz. Retrieved April 1, 2014, from http://www.tu-chemnitz.de/en/
1) By oxidation: Aromatic acids can be obtained by the oxidation of ‘side chain’ of benzene derivatives.
One of the most important uses of organic compounds is in medicine. All living things have four organic molecules - carbohydrates, proteins, lipids and nucleic acids. Without carbon chains and nucleic acids, DNA would not exist. Enzymes which produce chemica...