Stereochemistry Essays

Chiral phosphorus compounds are of great important in the fields of pharmaceutical chemistry1, materials2 and typically used as versatile ligands3 or oganocatalysts4 in asymmetric catalysis. Generally, transition-metal1a,5 or inorganic base6-promoted asymmetric P-C bond formation constitutes one of prominent strategy for the preparation of chiral phosphorus compounds possessing chiral centers at phosphorus and/or carbon atmos. In the recent years, organocatalytic asymmetric P-C bond formation from

Quantification and separation of chiral compound are considerable appealing because of the difference in pharmacological and toxicological properties of enantiomers. Sometimes one of the enantiomers demonstrates the desirable effect while the other could be less active or inactive or even have adverse effects.44 Several technique such as HPLC, supercritical fluid chromatography (SFC), and GC are used for separation of chiral compound. As a complimentary technique, capillary electrophoresis is also

Cyclohexanes give off an extremely high, unfavorable energy due to the spatial orientation of the atoms. Since these atoms are proximally close steric hindrance is observed. When comparing planar cyclohexanes with a chair conformation of a cyclohexane it is important to note how severe the angle strain, torsional strain, and steric strain could be. In planar cyclohexanes the torsional strain and angle strain is quite severe; this is because all C-C bonds are eclipsed (torsional) and all of the internal

Introduction Chiral molecules chemical structures that are non-superimposable mirror images of one another, much like the way a person’s hands are. Also known as stereoisomers, these compounds have the same molecular formula with different spacial orientation. Each chiral molecule contains a pair of enantiomers, each of which represents the two structures for each molecule (ie left hand and right hand). Chiral molecules play a huge part in pharmaceutical compounds, making up 56% of the drugs currently

There are several different reactions that can be used to synthesize an alkene product, however the main reaction being utilized for this experiment is the Wittig reaction and the Horner-Wadsworth-Emmons modification. The Wittig reaction involves a reaction between an aldehyde or ketone and ylid, which is also referred to as the Wittig reagent. The Wittig reagent is synthesized from a phosphonium salt and a strong base (Wittig Reaction, 2006). The reaction between the Wittig reagent and the ketone

After the assigned reaction was complete, samples of authentic cis-cyclohexene-1,2-diol, authentic trans-cyclohexene-1,2-diol, a 50:50 mix of the cis and trans cyclohexene-1,2-diols, and the product were each spotted on the Thin Layer Chromatography (TLC) plate. Then the TLC plate was placed inside a saturated beaker filled ethyl acetate in order to develop the plate. Once the solvent traveled up the solvent front, the plate was stained with anisaldehyde solution and then heated with a heat gun so

halogenation reaction through the addition of two bromides from pyridinium tribromide. This was accomplished by reacting trans-cinnamic acid with pyridinium tribromide. After the reaction took place, melting point analysis was conducted to find out the stereochemistry of the product, which could either be syn-addition, anti-addition, or syn + anti-addition. 2. Vacuum filtration was performed on the crude product, then it was recrystallized for purification. Melting point analysis was conducted on the recrystallized

Using this information to analyze the alkene peaks of the NMR spectra of the reactions using NaOH, KOH, or LiOH, one can conclude that the counter ion of the base used had no effect on the stereochemistry of the alkene formed from all three Wittig reactions ran in lab: all the NMR spectra show the same trans-alkene. Since there are two alkene protons in the product formed from all three Wittig reactions, there are two sets of peaks in the alkene

determined. In order to identify the stereochemistry of the alcohol, it will have to undergo an esterification reaction in which propionic anhydride, two enantiomers of HBTM(each used in different reactions), and triethylamine are used. Thin layer chromatography will be run at a specified time in the reaction, and the results will be examined both quantitatively(via ImageJ) and qualitatively to which reaction reacted more quickly. With this information, the stereochemistry of the alcohol can be deduced

to both the diene and the dienophile. A cis-dienophile gives cis-substituents in the product and a trans-dienophile gives trans-substituents. If the diene substituents have the same stereochemistry, the diene substituents would be on the same face of the product. If the diene substituents have opposite stereochemistry, the diene substituents would be on opposite faces of the product. The limiting reagent in the case of the experiment was the maleic anhydride. The

Chem 51LB Report Ngoc Tran - Student ID # 72048507 The purpose of this lab is to examine the composition of three components of gas products of elimination reaction under acidic condition by conducting the dehydration of primary and secondary alcohol, and under basic condition by conducting the base-induced dehydrobromination of 1-bromobutane and 2-bromobutane. Then gas chromatography is used to analyze the composition of the product mixtures. Gas chromatography (mobile phase) is used to analyze

group departs, forming a carbocation C+. In the second step, the nucleophilic reagent (Nuc :) attaches to the carbocation and forms a covalent sigma bond. If the substrate has a chiral carbon, this mechanism can result in either inversion of the stereochemistry or retention of configuration. Usually both occur without preference. The result is racemization. For an example (the reaction of tert-butyl chloride with water.) The SN2

Louis Pasteur (1822-1895) was a French chemist and microbiologist who became the face of many scientific practices used today. His discoveries can be categorised into molecular asymmetry, germ theory and immunology. His research has stood the test of time and his legacy remains in the form of the Pasteur Institute in Paris, where in 1888 the first ever course in microbiology was taught. Undoubtedly Pasteur has made a name and contribution in science, however; the significance can be questioned in

Experiment 7: Dihydroxylation of Cyclohexene and TLC Analysis Introduction The purpose of this experiment is to observe the formation of diol through two different reactions that are carried out with microscale techniques. It is to distinguish between stereoisomers, which means structures that differ in the spatial arrangement of atoms. The obtained products are then analyzed through TLC analysis to determine which stereoisomer of 1,2-cyclohexanediol is trans or cis compounds. Further on, this

One of the most used methods for the formation of six-membered rings is using the reactions of 1,3-diene with an alkene. The Diels-Alder reaction is a unique reaction in organic chemistry because it is a cycloaddition reaction. The Diels-Alder reactions are also known as 1,4 addition reactions due to the formation of new carbon-carbon σ bonds and π bonds. Electron-withdrawing groups like cyano (C≡N) and carbonyl (C=O) to increase the reaction rates and reaction yields (1). Often times there are

to being a synthetic organic chemist, and also mentioned several examples of synthetic challenges he has personally faced. Dr. Condeiu showed some real life examples of themes we discussed in class. In particular, I found his example of how stereochemistry is preserved during the hydrolysis of nerve agents intriguing. I also found it interesting that Phosphorus-Oxygen double bonds are common in nerve agents. Although not surprising, I never would have suspected it. Dr. Condeiu also showed how chiral

CARBOHYDRATES Carbohydrates are the most abundant biomolecules on Earth. Each year, photosynthesis converts more than 100 billion metric tons of CO2 and H2O into cellulose and other plant products. Carbohydrates are widely distributed in plants and animals; they have important structural and metabolic roles. In plants, glucose is synthesized from carbon dioxide and water by photosynthesis and stored as starch or used to synthesize the cellulose of the plant cell walls. Animals can synthesize carbohydrates

The purpose of this lab is to use the Diels-Alder reaction to combine anthracene and maleic anhydride. Named after its two founders the Diels-Alder reaction is the addition of a conjugated diene (electron rich compound) with a dienophile (electron poor compound). (1) These compounds will be combined using [4+2] cycloaddition, where the numbers 4 and 2 come from the number of π electrons that are used in each compound to synthesize the product. (2) This experiment comes at the cost of losing two π

Flucloxacillin: - It is a member of the penicillin family that is used as an antibiotic for the staphylococcal infection (bacterial infection) that affects the human tissues of the skin and the lungs (pneumonia). It is also used in the treatment of food (rotten food) and poisoning of theblood. Staphylococcus may also be a risk to the human life if it releases its toxins by some strains of the bacteria to cause toxic shock. - Flucloxacillin is prescribed mainly in Australia & Europe, as it is very

Since the conception of the Olympic games in ancient Greece, athletes have been participating in competitive sporting events to prove physical supremacy and acquire the honor and societal hierarchy that could be earned by the victors. In this infantile-era of athletic competition, the primary motivation for these athletes was simply to earn the coveted gold medal and obtain social prestige. However, in today’s hypercompetitive societal environment, a generic slab of gold is not a sufficient incentive