Williamson ether synthesis of phenacetin. Basai Lab 10 Williamson Ether Synthesis 2022-10-26
Williamson ether synthesis of phenacetin
The Williamson ether synthesis is a chemical reaction used to synthesize ethers, which are compounds containing an oxygen atom bonded to two carbon atoms. One of the most well-known examples of this reaction is the synthesis of phenacetin, a pain reliever that was once widely used but has since been discontinued due to its potential side effects.
The Williamson ether synthesis involves the reaction of an alkoxide ion with an alkyl halide, resulting in the formation of an ether. In the case of phenacetin, the starting materials are acetaminophen (analgesic) and ethyl bromide. The reaction is typically carried out in the presence of a base, such as sodium hydroxide, to facilitate the formation of the alkoxide ion.
The reaction begins with the protonation of the acetaminophen molecule, which is facilitated by the presence of the base. This generates the acetaminophen protonated form, which is more reactive than the neutral form. The ethyl bromide then reacts with the acetaminophen protonated form to form the intermediate compound, ethyl acetaminophenium bromide.
The intermediate compound then undergoes deprotonation, resulting in the formation of the ether, phenacetin. The deprotonation step is facilitated by the presence of the base, which acts as a proton acceptor. The reaction can be represented by the following equation:
Acetaminophen + Ethyl bromide + NaOH -> Phenacetin + NaBr
The Williamson ether synthesis is a useful method for synthesizing ethers, and it has been widely applied in the synthesis of various compounds, including pharmaceuticals, fragrances, and dyes. However, the reaction can also produce impurities, and the use of alkyl halides as starting materials can be hazardous due to their potential to form explosive compounds.
In conclusion, the Williamson ether synthesis is a chemical reaction used to synthesize ethers, including phenacetin. While this reaction is useful, it can also produce impurities and the use of alkyl halides as starting materials can be hazardous.
lab report 10
Due to the dangers of iodoethane, 1 mL is measured under the hood and placed into the flask. The first step when the alcohol is deprotonated by the use of a base in order to form an alkoxide ion. The identity of phenacetin product was successfully confirmed using the TLC plate analysis, melting point analysis, and IR and NMR spectroscopy. Very small amounts of material are presented, and very little original thought is shown. Inhalation anesthetics are introduced into the body via the lungs and distributed by the circulatory system. References Schotten-Baumann reaction ~ Name-Reaction. The first use of the Williamson ether synthesis was seen mainly used for precursors such as alcohol and alkyl halide.
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Finally, the third peak can be located between 5. Reflux means that a solution is heated in a controlled manner under stable but constant temperature without losing the solvent. The phenolic hydrogen is sufficiently acidic to be deprotonated by potassium carbonate to allow the reaction to occur. The remaining solvent was then evaporated in a preheated 50 C water bath and gentle air stream until 1 mL was left. How to synthesize N- hetero arylamide using amine activation? To add on, the apparatus provides less time required for the reaction to go to completion.
What is the synthesis of phenacetin?
The theoretical yield for the reaction was 1 g, and the experimental yield was 0. When potassium carbonate is present in a solution with acetaminophen it generates the conjugate base of acetaminophen which is powerful enough to pull apart iodoethane. In order to purify phenacetin and use the TLC method the product needs to be recrystallized. Data explained contains little thought and depth. Finally, the melting point of the product, phenacetin is then measured in order to compare to the literature value. However, by the 1880's, chincona trees, native to South America, had become scarce due to over-logging, prompting the development of alternative synthetic drugs. Also a melting point range of 124 o C-128 o C was observed.
Lab 10 Williamson Ether Synthesis Preparation of Phenacetin from Acetaminophen
The choice of solvents should allow for reasonable solubility when the solvent is at a high temperature and insoluble when the temperature is decreased. Yes or no, explain why. Once all the phenacetin was dissolved, the solution was removed from the heat and was cooled to room temperature. To produce molecules that can have a variety of uses, ethers should be used. Addition of carbon dioxide to a lithiated terminal alkyne enables the synthesis of acetylenic amides in one pot.
Williamson Ether Synthesis
A method for N — hetero arylamide synthesis based on rarely explored amine activation, rather than classical acid activation, shows a broad scope including challenging amides. Therefore, the Williamson Ether Synthesis is a very key process. This image is the molecular structure of phenacetin. Proceed to assemble an apparatus for heating under reflux, connect the round bottom flask to the reflux condenser and heat for one hour. Phenacetin is prepared by mixing 1 g of Acetaminophen with 1 g of Ethyl iodide in the presence of a base.
Laboratory 10 Williamson Ether Synthesis Preparation of Phenacetin from Acetaminophen (1)
The amount needed is based on when clumping is no longer visible. Tertiary alkyl halides cannot be used in the williamson ether synthesis because they are way too sterically hindered. Amines are efficiently acylated by both cyclic and acyclic anhydrides in aqueous medium with sodium dodecyl sulfate SDS — without use of acidic or basic reagents. The reaction rate in the second step SN2 reaction will depend on the total strength of the nucleophile. Details may be missing. For this experiment, ethyl acetate and 2-butanone are removed the product using the rotovap.
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The drying tube was assembled by adding anhydrous CaCl 2 a drying agent to the device and then plugging both ends with cotton. Significant amount was lost; slightly over half was lost from 0. So, methyl iodide forms dimethyl ether when heated with alcoholic sodium methoxide. To recrystallize the product and characterize it by melting point analysis and TLC. The data collected is explained and used to verify and prove the con- cluded outcome. Using alkoxide ions favors an elimination reaction with the aid of alkyl halide. The limiting reagent was acetaminophen because it contained the least number of moles from the starting reagents.
Free Essay: Williamson Ether Synthesis of Phenacetin
A rotary evaporator is then utilized to remove solvent from the solution. Acetaminophen possesses an alcohol group which means that it participates in hydrogen bonding, resulting in the bond interactions being very strong. The first peak located between 11. Potassium carbonate is the solvent that deprotonates hydrogen phenol in the reacion. Upon comparison between the measured melting point and the literature value, it can be said that the final product produced, phenacetin, was pure.
The reaction mechanism for the synthesis of phenacetin is shown below. It is to say that a strong base should be picked because if a very weak base is used, it will not proceed to There were various reagents used in this lab: acetaminophen, potassium carbonate, iodoethane, and 2-butanone. Calculations for table 2. The likelihood of elimination occurring increases with the increase in substitution of alkyl halides, and due to the alkoxides being powerful bases, they may cause the alkyl halide to change to the flask, along with g of potassium carbonate and 15 mL of In the fume hood, add 1mL of iodoethane to the mixture. Ethers play a crucial role in organic chemistry.
Once the phenacetin is dissolved it is then removed from heat and cooled to room temperature and finally placed in an ice bath. Next, the spinning is stopped, and the flask is removed from the rotary evaporator. Phenacetin contains functional groups such as methyl and amide functional groups. The vial was then attached to a drying tube and air condenser. There was the option of using either powder or crushing up tablets. Thin-layer chromatography was then performed to compare the purity of pure acetaminophen to that of phenacetin synthesized. Once the hour is complete the reaction was then cooled and placed into a vacuum filtration to filter out any solids.