Question

provide ALL the steps for the synthesis of tryptophan from phtalimido malonic ester and all the detailed mechanism

Answer 1

Last step is the solvolysis process where hydroxide ion attacks on the carbonil group of pthalimide and ester group to convert them amine and carboxylate group respectively. After acid hydrolysis followed by heating produces the desired tryptophan.

Answer 2

The synthesis of tryptophan from phthalimido malonic ester involves several steps. Here is a step-by-step guide along with the detailed mechanism:

Step 1: Preparation of Phthalimido Malonic Ester The synthesis begins with the preparation of phthalimido malonic ester. This compound can be obtained by reacting phthalimide with malonic ester in the presence of a base such as sodium ethoxide. The reaction proceeds through a nucleophilic substitution mechanism:

rustCopy codePhthalimide + Malonic Ester + Base -> Phthalimido Malonic Ester + Byproduct

Step 2: Hydrolysis of Phthalimido Malonic Ester The next step involves the hydrolysis of the phthalimido group in the ester to form a carboxylic acid. This can be achieved by treating the phthalimido malonic ester with a strong acid, such as hydrochloric acid. The reaction proceeds through an acid-catalyzed hydrolysis mechanism:

rustCopy codePhthalimido Malonic Ester + Acid -> Carboxylic Acid + Phthalimide

Step 3: Decarboxylation and Aromatic Rearrangement The carboxylic acid obtained in the previous step undergoes decarboxylation and an aromatic rearrangement reaction to form an intermediate compound. This reaction is carried out by heating the carboxylic acid in the presence of a dehydrating agent, such as phosphorus pentoxide (P2O5). The reaction proceeds through a series of steps involving the loss of carbon dioxide and rearrangement of the aromatic ring.

Step 4: Reduction of Intermediate Compound The intermediate compound obtained in the previous step is then reduced to form an amino acid derivative. This reduction can be achieved using a reducing agent such as lithium aluminum hydride (LiAlH4) or sodium borohydride (NaBH4). The reduction reaction involves the addition of hydride ions to the carbonyl group, resulting in the formation of an alcohol.

Step 5: Hydrolysis and Decarboxylation The amino acid derivative is then hydrolyzed and decarboxylated to yield the final product, tryptophan. This reaction is typically carried out by treating the amino acid derivative with a strong acid, such as hydrochloric acid, and heating the mixture. The hydrolysis reaction cleaves the amide bond and converts the amino acid derivative into an amino acid. Subsequently, the decarboxylation reaction removes the carboxyl group, leading to the formation of tryptophan.

Overall, the synthesis of tryptophan from phthalimido malonic ester involves the preparation of the ester, hydrolysis of the ester, decarboxylation and aromatic rearrangement, reduction of the intermediate compound, and hydrolysis and decarboxylation of the amino acid derivative. The detailed mechanisms for each step involve various chemical transformations and reactions, which can be quite complex to illustrate in a text-based format. It is recommended to refer to organic chemistry textbooks or scientific literature for a more comprehensive understanding of the detailed mechanisms involved in each step.