1. Introduction Epoxides (or oxiranes) are highly versatile intermediates in synthetic organic chemistry. Nature also uses them as intermediates in many key biosynthetic pathways. However, there are other functions of epoxides in biological systems. They can impart localised structural rigidity, confer cytotoxicity by alkylation, or be secondary metabolites [1]. The chemistry of epoxides is dominated by the reactions that involve opening of the strained three-membered heterocyclic ring by nucleophiles. Such reactions yield valuable bifunctional compounds. In nature, epoxide ring opening is catalysed by the phenolic proton of a tyrosine moiety [2]. But in laboratory, the cleavage usually occurs in non-aqueous media in presence of a Lewis acid catalyst like Al2O3, Li+, Mg2+ etc. Additionally often elevated temperature and excess of nucleophiles are required. There are a few reports where use of a catalyst has not been necessary [3,4]. For example, aminolysis of epoxide by an -amino acid ester proceeds smoothly in refluxing trifluoroethanol [3]. The same reactions fail in water. In contrast, aliphatic and aromatic amines are found to cleave an epoxide ring in water at room temperature without any Lewis acid catalyst [4]. Herein we report opening of an epoxide group present in a chelate ring of a metal complex by aromatic amines …show more content…
Results and discussion Stirring of L with 4-methylaniline and 4-methoxyaniline in equimolar proportion in water at room temperature for 72 h without any Lewis acid catalyst gives L.H2O and L respectively (Scheme 1). The yield of L.H2O is 90% and that of L 70%. These are obtained in 60% yield when the reactants are refluxed in water for 14 h. But the yield goes on decreasing when increasingly more refluxing time is used. Earlier Moody et al have [5] studied opening of the epoxide ring in L in connection with their total synthesis of the pentacyclic marine alkaloid ascididemin from 1,10-phenanthroline (phen).
In this lab, the oxidation of a secondary alcohol was performed and analyzed. An environmentally friendly reagent, sodium hypochlorite, was used to oxidize the alcohol, and an IR spectrum was obtained in order to identify the starting compound and final product. The starting compound could have been one of four alcohols, cyclopentanol, cyclohexanol, 3-heptanol, or 2-heptanol. Since these were the only four initial compounds, the ketone obtained at the end of the experiment could only be one of four products, cyclopentanone, cyclohexanone, 3-heptanone, or 2-heptanone. In order to retrieve one of these ketones, first 1.75g of unknown D was obtained.
Grignard is a reaction that is crucial to forming the new carbon-carbon bond. This is a two-part lab that teaches new techniques; the purpose of this lab is to introduce realistic organic synthesis and apply acid workup to produce triphenylmethanol. A Grignard reaction is characterized by the addition of a magnesium halide (an organomagnesium halide) to an aldehyde or a ketone in order to form a secondary or tertiary alcohol. These reactions are helpful because they serve as a crucial tool in performing important carbon-carbon bond-forming reactions (Arizona State University, 2018). This experiment aimed to observe the mechanisms of a Grignard reply to synthesize triphenylmethanol from benzophenone using phenylmagnesium bromide as the Grignard reagent.
For this experiment, stereochemistry was observed by analyzing both the isomerization of dimethyl maleate and carvones. The dimethyl maleate is formed by two methyl ester groups that are connected by an alkene. They are in a cis-conformation meaning they are on the same side of the alkene, therefore the esters are close to one another. This conformation is strained and sterically hindered due to electrons repelling each other and are enantiomers of one another. With the use of radical chemistry, the cis conformation can be changed into a trans configuration where the esters are on opposite sides of one another.
The reaction was allowed to proceed for 30 minutes and was subsequently quenched using hydrochloric acid. The addition of hydrochloric acid permitted the protonation of the reduced ketone (O-) to form the two diastereomer
In the presence of a nucleophile and good leaving group, an organic reactant in specific conditions is likely to undergo a chemical reaction, namely, nucleophilic substitution. Nucleophilic substitution consists of two different mechanisms, SN1 and SN2. In this experiment, SN2 is the mechanism tested. SN2 is a relatively fast, one-step mechanism in which the nucleophile attacks the organic reactant and the leaving group diverges from the reactant to become a weak base (Fig. 1). The overall speed of the reaction can increase based on the size or basicity of the nucleophile, or the bulkiness of the carbon group with the leaving group.
The reaction to synthesize benzocaine was known as a Fisher esterification reaction. The Fisher esterification was reaction between alcohol and carboxylic acid in the presence of acid. The reaction was used to form an ester. In the experiment, sulfuric acid acted as a catalyst and necessary for this reaction to occur. There was a change between the –OH group of carboxylic acid to an –OCH2CH3 group in the reaction.
Abstract: Gel electrophoresis is a method used to separate DNA fragments according to size. During our study we pondered on one particular question; whose blood was left at the crime scene in the AP biology classroom? Before carrying out our experiment we learned about the process of gel electrophoresis and the use restriction enzymes. After analyzing our results, we decided to reject our hypothesis because our experiment showed strong evidence against what we originally hypothesized.
The purpose of this experiment is to perform a two step reductive amination using o-vanillin with p-toluidine to synthesize an imine derivative. In this experiment, 0.386 g of o-vanillin and 0.276 g of p-toluidine were mixed into an Erlenmeyer flask. The o-vanillin turned from a green powder to orange layer as it mixed with p-toludine, which was originally a white solid. Ethanol was added as a solvent for this reaction. Sodium borohydride was added in slow portion as the reducing agent, dissolving the precipitate into a yellowish lime solution.
Dr. Condeiu’s presentation on synthetic organic chemistry was a rewarding experience because he touched on some very important concepts. Not only did he mention many of the things discussed in class in terms of real world examples, but he also brought a human face 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.
Drapex 6.8, supplied by Galata Chemicals from Louisiana, was the ESO used. Boron trifluoride diethyl etherate, dimethyl benzyl amine, hexanoic anhydride (97%), n-hexanoic acid (99%) and n-octanoic acid (99%) were obtained from Sigma-Aldrich, USA, while sodium chloride and sodium bicarbonate were obtained from Fisher Scientific, USA and used as received. The AMC-2 catalyst was purchased from Aerojet Chemicals, California, US. Epon 828 (epoxy equivalent weight, EEW 185-192 g/eq. Hexion technical data sheet of Epon 828 issued September 2005) and Epon 1001F (EEW 525-550 g/eq.
It is understood the mechanism is acid-catalyzed where protons coordinate with the carbonyl oxygen to make the carbonyl carbon more electropositive for nucleophilic attack (Scheme 1). In the experimental procedure all reactants were added together, this is inefficient as the protons can coordinate with either trans-cinnamic acid or methanol. Coordination with methanol is unnecessary as it reduces its nucleophilicity and makes less protons available to coordinate with the carboxylic acid. To improve
Electrophoresis – An Introduction • An analytical technique in which the motion of scattered particles run through a fluid under the influence of uniformly charged field is called electrophoresis. • This phenomenon was first observed by Ferdinand Frederic Reuss followed by Arne Tiselius who won the Nobel Prize in chemistry for his research on electrophoresis, adsorption analysis and his discoveries concerning the complex nature of serum protein. It is a technique used in laboratories in order to separate macromolecules based on molecular size and charge. • This technique applies a negative charge so proteins move towards a positive charge.
N-arylsulfonyl tryptophanderivatives were investigated as ligands for the reaction due to “the high π-electron-donating characterof the indole ring” (?) B-n-butyloxazaborolidine was used at 5 mol% to accelerate and control the reaction of cyclopentadiene and 2-bromoacrolein (-78 °C) in DCM. Enantioselectivity of the desired 2R adduct occurred at ca. 200:1 with a high yield. This catalyst can be used to enantioselectively produce gibberellic acid, a plant hormone, as well as the antiulcer agent, cassiol and eunicenone.
Introduction Gel electrophoresis is a technique used to separate biomolecules such as DNA, RNA, and proteins. DNA can be separated according to their size. First, in a technique called polymerase chain reaction (PCR), large amounts of DNA are replicated from a trace amount. The trace amount can come from a hair, a drop of blood, or a cheek cell. After DNA is generated, it is placed in chambers in the electrophoresis gel.
The chemistry of heterocycles compounds is one of the most complex branches of chemistry. It is equally interesting for its theoretical implication for the diversity of its synthetic procedure and for the physiological and industrial significance. Synthetic heterocycles chemistry has influenced almost every place of human life and the heterocycles compounds have found their application in diverse fields medicine, agriculture, polymer, and various industries. Synthetic heterocycles drugs are used as Hypnotics, Anticonvulsants, Antiseptics, Antineoplastics, Antiviral, Antihistaminic, Anti-tumor etc. Majority of the large number of drugs being introduces in pharmacopeias every year are heterocycles