Decarboxylation reaction is an important reaction in organic chemistry. Decarboxylation reaction can convert carboxyl group to other active groups, or just remove carboxyl group in order to get target molecules. In ethyl acetoacetate synthesis, if we want to synthesis a ketone, the last step will be decarboxylation reaction. And decarboxylation reaction is also the last step of Darzens reaction, which undergoes rearrangement step and finally converts carboxyl group to aldehyde group1-5.
Conventionally, many carboxylic acids can occur decarboxylation reaction only if they have special structures, such as β-carbonyl carboxylic acid. However, common fatty acid cannot occur decarboxylation reaction under common acid or base conditions6. An exception is acetic acid, which can generate methane when heated with base. One method is that carboxylic acids occur decarboxylation reaction under lead tetraacetate7-8. When the alkyl group connecting with carboxyl group is third-order, the product will be alkenes with high yields. And when the alkyl group is first-order or second-order, if we use cooper
…show more content…
In 2015, Wong and Zhou Group37 used a library of P450 mutants to test the activities of drug oxidation decarboxylation. Although no single mutant showed high activities to all drugs, multiple mutants in this library showed high activities with some of the drugs. Li Group38 expanded substrates to triacyclglycerols and oils, which are renewable. Since this method only needs two catalytic steps, it can be used in large scales and it is cost-efficiency for production of advanced biofuels. Faber Group39 even developed decarboxylation reaction for dioic acids, which can provide two vinyl groups terminally. Reetz Group40 researched on P450’s regioselectivity, they concluded that the new-formed vinyl group in prone to conjugate with existing vinyl
Wittig reactions allow the generation of an alkene from the reaction between an aldehyde/ketone and a ylide (derived from phosphonium salt).The mechanism for the synthesis of trans-9-(2-phenylethenyl) anthracene first requires the formation of the phosphonium salt by the addition of triphenylphosphine and alkyl halide. The phosphonium halide is produced through the nucleophilic substitution of 1° and 2° alkyl halides and triphenylphosphine (the nucleophile and weak base) 4 An example is benzyltriphenylphosphonium chloride which was used in this experiment. The second step in the formation of the of the Wittig reagent which is primarily called a ylide and derived from a phosphonium halide. In the formation of the ylide, the phosphonium ion in benzyltriphenylphosphonium chloride is deprotonated by the base, sodium hydroxide to produce the ylide as shown in equation 1. The positive charge on the phosphorus atom is a strong EWG (electron-withdrawing group), which will trigger the adjacent carbon as a weak acid 5 Very strong bases are required for deprotonation such as an alkyl lithium however in this experiment 50% sodium hydroxide was used as reiterated. Lastly, the reaction between ylide and aldehyde/ketone produces an alkene.3
The objective of this experiment was to conduct the Friedel-Crafts Alkylation of p-xylene. This reaction substituted an alkyl group instead of a hydrogen atom on the aromatic ring. The compound used was p-xylene, the reactant was n-propyl chloride, and the Lewis acid catalyst was aluminum chloride. The products consisted of the group of n-propyl that combined with p-xylene to form 1,4 Dimethyl-2-propylbenzene, and the group of isopropyl that combined with p-xylene to form 2-isopropyl-1,4-dimethylbenzene
... which is catalyzed by b-ketoacyl CoA thiolase. The products are acetyl-CoA and a long chain fatty acyl CoA that is 2 carbons shorter than the original fatty acyl CoA. One complete round of β-oxidation cleaves 2 carbons from the fatty acid chain, and the process continues until the entire fatty acid chain is broken down into acetyl propinoyl CoA. For example, an 18 carbon chain fatty acid would need to go through 9 rounds of β-oxidation in order to be completely metabolized.
For this experiment, three separate pathways were designed to utilize the exact same reagents in different orders to create a synthesis from acetophenone to methyl m-nitrobenzoate. This experiment was constructed in this format to evaluate the efficiency and overall percent yield of each pathway to determine which is most effective in synthesizing methyl m-nitrobenzoate. The pathway implemented in this experiment used acetophenone as its starting material and converted it to benzoic acid. The benzoic acid was then nitrated to m-nitrobenzoic acid, and the m-nitrobenzoic acid transformed into methyl m-nitrobenzoate.
need is water and an ester and we will end up with an organic acid produced as
In 1935, Robert Robinson and his colleague William Sage Rapson published a series of articles for the Journal of the Chemical Society. In them, Robinson and Rapson detail how they performed a number of experiments that synthesized molecules similar in structure to sterols. In particular, Part 7 of their experiments describes what is today known in organic chemistry circles and classrooms alike as the Robinson Annulation Reaction. Figures 1 and 2 above demonstrate two examples of the mechanism for the Robinson Annulation Reaction. In Robinson’s words (1935), this reaction involves a ketone that “might undergo double cyclisation” with formation of a new structure (p. 1533). The Robinson Annulation Reaction constructs a new ring (for example, a six-membered ring) from the original starting ketone found in the reactants. Typically, a structure known as an enolate (the anion formed when an alpha hydrogen in the molecule of an aldehyde or a ketone is removed as a hydrogen ion and contains a double bond because it is resonance stabilized—source: science.uvu.edu) would be added to a methyl vinyl ketone or other enone (compound containing a ketone and an alkene). This process is also known as a base-catalyzed Michael addition. Dehydration, or removal of H2O, then occurs to give a cyclohexenone product.
Fischer Esterification is a unique type of esterification first discovered by Emil Fischer and A Speier in 1895. Fischer Esterification is a mechanism of which an ester is formed as a product when a carboxylic acid is treated with an alcohol and an acid catalyst. Together with ester, water is also liberated on this reaction. The key bonds formed in this reaction is C-OR, of which the oxygen bonded to carbon is the oxygen from the alcohol, not the oxygen originally bonded to it from the starting carboxylic acid. The key bonds broken is C-OH, the oxygen from the carboxylic acid bonds with the hydrogens that will then form water. So, the reaction does not simply just break the H and the R but rather -OH and -OR. This reaction is an equilibrium reaction. Applying Le Chatelier’s principle, if alcohol is used as a solvent to carboxylic acid and have a small amount of water (product), then the reaction would favor the product. On the other hand, if the reaction is to go backwards, whereas the reaction would start from an ester going to a carboxylic acid, then the water would be used as a solvent. Common acid catalyst are sulfuric acid, tosylic acid, and Lewis acids such that of scandium(III) triflate. Tertiary alcohols are prone to elimination whereas phenols
The experiment begins with the condensation of benzoin (eq. 1). In the presence of the thiamine catalyst, the 2 benzaldehyde molecules condense to produce benzoin when they are heated with sodium hydroxide and ethanol.
Fatty acids are constructed by a chain of various amount of carbon atoms attached to hydrogen atoms. Fatty acids can be categorized into three groups based on the number of carbon atoms: short-fatty acids (SCFAs) ≤ C5, medium-chain fatty acids (...
While the esterification reaction was under reflux, the aldol condensation procedure was performed. The hot plate was turned to
The goal of this experiment is to determine which products are formed from elimination reactions that occur in the dehydration of an alcohol under acidic and basic conditions. The process utilized is the acid-catalyzed dehydration of a secondary and primary alcohol, 1-butanol and 2-butanol, and the base-induced dehydrobromination of a secondary and primary bromide, 1-bromobutane and 2-bromobutane. The different products formed form each of these reactions will be analyzed using gas chromatography, which helps understand stereochemistry and regioselectivity of each product formed.
14. Erucic acid is a long-chain unsaturated fatty acid. Like oleic acid, it suppresses the creation of VLCFSAs, but is much more
In the oxidation of borneol to camphor, a hydrogen is removed from the carbon attached to the hydroxy group. In order for the all the atoms to have octets, the charged carbon forms double bonds with the oxygen atoms. The product produced is camphor.
Toluene hydrodealkylation process is irreversible process and requires catalyst. The catalyst used in this process consist of molybdenum oxides or chromium, platinum oxides or platinum, silica or alumina. Minor reversible side reaction is:
As shown in Scheme 2, the consecutive oxidations of methyl group take place for p-toluic acid and 4-CBA. In order to gain terephthalic acid as the end product, the purification from impurities including 4-CBA content in crude terephthalic acid must be conducted. In purification process, the crude terephthalic acid (a solid terephthalic acid that has been undergoing centrifugation and drying) will be dissolved in hot water to reduced 4-CBA to p-toluic acid. This reduction process is through catalytic hydrogenation on palladium catalyst. Then, the purified terephthalic acid is obtained [33]. Apart AMOCO process, the other catalytic process to produce terephthalic acid by direct oxidation was widely st...