.1.1 CYTOSINE ANALOGUE PREPARATION WITH AROMATIC ALDEHYDE when aromatic aldehyde is used, magnesium is added to anhydrous methanol or ethanol (4 eq relative to cytosine) and heated until complete dissolution of magnesium filings and add 2 mmol of cytosine, followed by the aromatic aldehyde in the amount of 4-6 eq, minimum of 4 eq relative to cytosine, the reaction mixture is heated up to 45-65°C for at least 3 hours, and later, a reducing agent, preferably NaBH(1 eq relative aldehyde) ,is added to the cooled mixture, then it is kept at room temperature for at least 15 minutes, followed by addition of inorganic acid solution; next, the mixture is evaporated, water is added and the mixture is extracted with ethyl acetate to isolate the product; …show more content…
Hardee and his group developed a process of activation of aliphatic carboxylic acids taking 3, 3-dichlorocyclopropenes in presence of tertiary amine base , DIPEA (diisopropylethylamine)[22] FIGURE 3.3 ACTIVATION OF ALIPHATIC ACID Racemization is frequent in the course of coupling reaction at the C-terminal amino acid residue due to the ionization of the α-hydrogen atom and formation of an oxazolone intermediate in peptide synthesis, so of course this will not reagent of choice in peptide synthesis, where suitable peptide coupling reagent can be selected, which is out of scope of this review.[22] 3.2 SELECTED PROCESS Out of all the processes mentioned in the survey, these processes were selected on the behalf of having most appropriate reaction conditions and environment of the research lab, i.e modification with …show more content…
in the first step benzoic acid was reacted with excess of thionyl chloride using acetonitrile as a solvent and keeping the mixture on an ice bath for 3-4 hours (labeled as reaction mixture a) In the second step gemcitabine hydrochloride along with 3eq tri-ethyl amine and using ethanol again as a solvent was stirred for 15-20 minutes without ice-bath. next with a poisterizing tube the reaction mixture a was drop wise added to reaction mixture b yielding a third and final, reaction mixture c giving off white fumes of socl2. it is stirred for 19 hours and 15minutes at 80c and colour changes to light yellow The preparation of benzoyl chloride from benzoic acid using thionyl chloride at 0’c is an in-situ preparation procedure: FILTERATION: Evaporate reaction mixture and dissolved in hexane and then filter it. The best TLC system for filterate is ethyl acetate : hexane , 4.5:0.5 3.3.2 PROCESS 2 FIGURE 3.5ACETYL DERIVATIVE PROCEDURE In 75mg of gemzar, 2ml ethanol is added and then solubility is checked. After 5 minutes add 0.1 ml (5 drops) DMF, then add 0.104ml Et3N and add 0.036 ml acetyl chloride and stirr it for 17 hours r at 47C
After 28 minutes, the mixture stopped boiling, and approximately 4.5 ml of bromobenzene was added drop by drop in the mixture, and color of the mixture was turned light brown orange. Then, the phenylmagnesium bromide was cooled in ice bath for a few minutes, and 10 ml of anhydrous diethyl ether was added in the mixture by using the syringe. After that, approximately 2.3 ml of methyl benzoate was added to the reaction, and it was added slowly slowly because the reaction was exothermic which needed to be cool in order to maintain a gentle reflux. Once all the methyl benzoate solution was added, the heating mantle was removed from the reaction flask and was cooled to the room temperature. During the reaction, a milky white salt began to precipitate, and the reaction flask was swirled for ten minutes until most of the reaction became visibly subdivided.
Marissa De la Paz 29 October 2015 Landstrom T/R, 8am Experiment 13B: Phenyl Grignard Addition to Benzophenone The objective of this experiment is to first generate a Grignard reagent, then use that to synthesize triphenylmethanol. The Grignard reagent is necessary to create a new C—C bond. The formation of triphenylmethanol is broken down in several steps.
In this experiment, the combined reactions are as follows. To start the experiment, the Grignard reagent, phenylmagnesium bromide, was formed by reacting bromobenzene with magnesium while using anhydrous diethyl ether as the solvent. Using anhydrous ether is crucial because if any water is present, the Grignard reagent will react with the water instead, which will ultimately terminate the reaction. Once formed, the Grignard reagent reacted with the benzophenone to form triphenyl magnesium bromide; this served as the Grignard adduct. From there, the Grignard adduct underwent an acid workup using aqueous 6M hydrochloric acid in order to form the product triphenylmethanol.
Each amino acid is made up of an amino group, a carboxyl group and a side chain (Reece, J. B., Urry, L. (2016). Campbell biology. Boston Pearson). Enzymes work by lowering the activation energy of the reaction making the reaction produce faster. Enzymes begin to catalyze chemical reactions with the binding of the substrate to the active site on the enzyme.
The purpose of this experiment was to learn about the electrophilic aromatic substitution reactions that take place on benzene, and how the presence of substituents in the ring affect the orientation of the incoming electrophile. Using acetanilide, as the starting material, glacial acetic acid, sulfuric acid, and nitric acid were mixed and stirred to produce p-nitroacetanilide. In a 125 mL Erlenmeyer flask, 3.305 g of acetanilide were allowed to mix with 5.0 mL of glacial acetic acid. This mixture was warmed in a hot plate with constantly stirring at a lukewarm temperature so as to avoid excess heating. If this happens, the mixture boils and it would be necessary to start the experiment all over again.
“The starting amino acid is highly soluble in the acidic solution of the reaction, the amphoteric nature of L-phenylalanine is apparent at the start of the reaction”. “The L-phenylalanine solution is cooled and then the aqueous NaNO2 solution is added with stirring”. “The reaction mixture begins to form tiny bubbles as the diazonium salt forms and nitrogen gas is liberated by the intramolecular reaction with the carboxylic acid”. “Reaction occurring as the Nitrogen bubbles form”. “This rapid intramolecular reaction reinforces the concepts
In case of chloramphenicol, the dichloroacetamido group is oxidized to an oxamyl moiety that acylates a lysine residue in the CYP active site; leads to CYPs enzyme inhibition (Juinn et. al., 1998). Quasi-Irreversible
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.
React ethanoic acid and 1-butanol under reflux with the presence of trace amount of concentrated sulfuric acid. In this step, the amount of 1-butanol and ethanoic acid used is the same so that a maximum 70% ester yield can be synthesised at the end of the experiment. After the reactants is accommodated in the reactant flask, the trace amount of concentrated sulfuric acid is added drops-by-drops into the reactant flask and the flask is swirled while adding the acid. Additional of concentrated sulfuric acid is to use as a catalyst to increase the rate of reaction by donating a proton to the oxygen atom in carboxylic acid to allow for the mechanism for esterification and thus, the satisfactory yield of ester can be achieved.
The yellow solution containing the reactants was slowly poured into the beaker containing the cold water and the acid in order to cause the precipitation of the alcohol, 9-fluorenol and to destroy (hydrolyzed) the unreacted excess sodium borohydride. Subsequently, the white precipitate was vacuum filtered and washed twice with 20.0 ml portions of distilled cold water by pouring the liquid into the Buchner Funnel during filtration. It was necessary to wash the alcohol prior to recrystallization considering that the C-OH bond is easily broken by the formation of a stable and benzylic carbocation that favors the synthesis of difluorenyl ether. Finally, before the purification by recrystallization of the obtained product, the white solid alcohol was allowed to dry over a period of a
Next, the oxygen is protonated from the 3-nitrobenzaldehyde, which is then followed by an elimination reaction where this acts as a leaving group. The product is the trans-alkene present in the product. After the reaction was completed, purification of the product was conducted using semi-microscale recrystallization.
Experiment 2 Report Scaffold (Substitution Reactions, Purification, and Identification) Purpose/Introduction 1. A Sn2 reaction was conducted; this involved benzyl bromide, sodium hydroxide, an unknown compound and ethanol through reflux technique, mel-temp recordings, recrystallization, and analysis of TLC plates. 2. There was one unknown compound in the reaction that was later discovered after a series of techniques described above.
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
Purpose/Introduction The process of recrystallization is an important method of purifying a solid organic substance using a hot solution as a solvent. This method will allow the separation of impurities. We will analyze Benzoic Acid as it is dissolved and recrystallized in water and in a solvent of Methanol and water. Reaction/Summary
After degradation of proteins either by autolysis or by bacterial proteolysis, free amino acids are formed which act as precursors of biogenic amine with the aid of decarboxylase enzymes. Straub et al. (1995) mentioned that the biogenic amines in foods are mainly formed by amino acid decarboxylation of bacteria. During a fermentation process the protein breakdown products, peptides