Nucleophile And Aldol

Abstract: Using hypochlorous acid to convert secondary alcohol called cyclododecanol to the corresponding ketone which is cyclododecanone by oxidation.

Note that the enzyme remains unchanged so that more of the some substrates can react.

The synthesis of acetaminophen involves the attraction of the electrophilic carbonyl group of acetic anhydride to the nucleophilic NH2

The reaction involves a nucleophilic acyl substitution on an aldehyde, with the leaving group concurrently attacking another aldehyde in the second step. First the Potassium hydroxide attacks a carbonyl, which forms a tetahedral intermediate which then collapses when attacked by another hydroxide. The carbonyl is formed again when its hydride attacks another carbonyl. In the final step of the reaction, the acid and alkoxide ions formed exchange a proton. In the presence of a very high concentration of base, the aldehyde first forms a doubly charged anion from which a hydride ion is transferred to the second molecule of aldehyde to form carboxylate and alkoxide ions. Subsequently, the alkoxide ion acquires a proton from the solvent.

When the two smaller reactants join together, water is produced and removed during the synthesis of the larger molecule. This is also called Dehydration Synthesis.

A unimolecular nucleophilic substitution or SN1 is a two-step reaction that occurs with a first order reaction. The rate-limiting step, which is the first step, forms a carbocation. This would be the slowest step in the mechanism. The addition of the nucleophile speeds up the reaction and stabilizes the carbocation. This reaction is more favorable with tertiary and sometimes secondary alkyl halides under strong basic or acidic conditions with secondary or tertiary alcohols. In this experiment, the t-butyl halide underwent an SN1 reaction. Nucleophiles do not necessarily effect the reaction because the nucleophile is considered zero order, (which makes it a first order reaction.) The ion that should have the strongest effect in an SN1 reaction is the bromide ion. The bromide ion should be stronger because it has a lower electronegativity than chloride as well as a smaller radius.

In this preparative lab, an aldol (trans-p-anisalacetophenone) was produced from the reaction between p-anisaldehyde and acetophenone with the presence sodium hydroxide. The reaction also showed the importance of an enolate and the role it played in the mechanism. Sodium hydroxide acts as a catalyst in this experiment and is chosen because of its basic conditions and pH. The acetophenone carries an alpha hydrogen that has a pKa between 18 and 20. This alpha hydrogen is acidic because of its location near the carbonyl on acetophenone. When the sodium hydroxide is added, it deprotonates the hydrogen and creates an enolate ion. This deprotonation creates a nucleophilic carbon that can attack an electrophilic carbon (like a parent

Then, a shift is observed by one of the atoms to the carbocation. And finally, to stabilize the molecule, catalyst is then regenerated to yield the final product.

Adding 3μl of 20mM ATP solution to the reaction mixture started the reactions. Control reactions were carried

The bromide ion is the better nucleophile than the chloride ion because of its larger size and since it is a weaker base. The chloride ion is more electronegative than bromide ion, so it tends to hold electrons in closerE. Since the bromide ion is less electronegative and has more electrons, it is able to share unpaired electrons easier than the chloride ion. In the case of this laboratory experiment, bromide was the better nucleophile in the protic solvent containing hydrogen bonded to oxygen of 1-butanol and 2-methyl-2-butanol as the protic solvent molecules formed strong ion-dipole interactions with the negative-charged nucleophile of the bromide ion, which created a solvent barrier around the nucleophileG. For the electrophile to be attacked

Enzymes are central to every biochemical process. Due to their high specificity they are capable of catalyzing hundreds of reactions that signifies their vast practical importance.

The oxidation reaction occurs as a two-step reaction. The first step involves the formation of chromate esters and the second step is an elimination reaction that will produce the carbonyl group necessary to make either a ketone or an aldehydes. The reaction is hallmarked by the breaking of a C-H bond and the formation of a C-O bond (James, 2014). Specifically when oxidizing alcohols, it is important to note that primary alcohols can be converted to aldehydes as well as completely to carboxylic acids, secondary alcohols are converted to ketones and no further, and tertiary alcohols cannot be oxidized. The oxidizing agent removes the hydrogen from the –OH group and the hydrogen from the C-H group attached to the –OH group in a compound. Tertiary alcohols cannot be oxidized because they lack the C-H bond that is present in both the oxidation of primary and secondary alcohols (Clark, 2003).

Both SN1 and SN2 reactions are nucleophilic substitution reactions. The main difference is their rate-determining step. For SN1 reaction, the rate-determining step is unimolecular where for SN2 reaction is bimolecular. In this experiment, an intermediate is formed. After the halide has been completely removed and the nucleophile has been added, the reaction terminates and leads to an inversion of stereochemistry. SN2 reaction is favoured because it gives a product with predictable stereocenter as it proceeds through an inversion of

The aldol reaction is a means of forming carbon-carbon bonds in organic chemistry. Discovered independently by the Russian chemist Alexander Borodin in 1869 and by the French chemist Charles- Adolphe Wurtz in 1872, the reaction comvines two carbonyl compounds to form a new B-hydroxy carbonyl compound. These products are known as aldols, from the aldehyde + alcohol, a structural motif seen in many of the products. Aldol structural units are found in many important molecules, whether naturally occuring or synthetic. For example, the aldol reaction has been used in the large-scale production of the commodity chemical penaerythritol and the synthesis of the heart disease drug Lipitor.

In base catalyzed aldol condensation of cyclohexanone (A), KOH or NaOH acts as a non–nucleophilic agent. In presence of base, cyclohexanone initially turns to enolate by losing αhydrogen. The formed enolate then reacts with the carbonyl group of the second molecule and leads to the formation of aldol intermediate. The polymerization reaction proceeds further by the reaction between the carbonyl group of third molecule and the activated methylene group of the second molecule. In the present study, the effect of reaction parameters on conversion of cyclohexanone and the product properties was extensively analyzed. The most probable dimeric (monomer repeating unit (n) =1) and polymeric (n