Skip to main content
Ch. 27 - Carbohydrates, Nucleic Acids, and Lipids
Mullins - Organic Chemistry: A Learner Centered Approach 1st Edition
Mullins1st EditionOrganic Chemistry: A Learner Centered ApproachISBN: 9780137566471Non è quello che usi tu?Cambia libro di testo
Tutti i libri di testoMullins 1st EditionCh. 27 - Carbohydrates, Nucleic Acids, and LipidsProblema 80
Capitolo 26, Problema 80

A derivative of chitin, called chitosan, is sometimes incorporated into bandages to aid healing. Propose a reaction to convert the chitin dimer into a chitosan dimer. [Note: The glycoside linkage is unstable in acid.]
Chemical structures of chitin and chitosan with a question mark indicating a proposed reaction for conversion.

Guida verificata passo dopo passo
1
Identify the structural difference between chitin and chitosan. Chitin has an acetamido group (NHCOCH3) on the C-2 position of the glucosamine unit, while chitosan has an amino group (NH2) at the same position.
Recognize that the conversion from chitin to chitosan involves the removal of the acetyl group from the acetamido group, which is a deacetylation reaction.
Propose a reaction condition that can achieve deacetylation. This typically involves treating chitin with a strong base, such as sodium hydroxide (NaOH), which can cleave the acetyl group.
Consider the reaction mechanism: The base will attack the carbonyl carbon of the acetamido group, leading to the removal of the acetyl group and formation of the free amino group.
Ensure that the reaction conditions are mild enough to prevent the hydrolysis of the glycosidic linkage, as it is unstable in acidic conditions. Therefore, using a basic environment is suitable for this transformation.

Risposta video verificata per un problema simile:

Questa soluzione video è stata consigliata dai nostri tutor come utile per risolvere questo problema.
Durata del video:
1m

Concetti chiave

Ecco i concetti essenziali che devi comprendere per rispondere correttamente alla domanda.

Chitin and Chitosan Structure

Chitin is a biopolymer made of N-acetylglucosamine units linked by β(1→4) glycosidic bonds. Chitosan is derived from chitin through deacetylation, where the acetyl groups are removed, resulting in a polymer of glucosamine units. Understanding the structural differences between these two polymers is crucial for proposing a reaction that converts chitin to chitosan.
Video consigliato:
03:04
Drawing Resonance Structures

Deacetylation Reaction

Deacetylation is a chemical reaction that involves the removal of an acetyl group from a molecule. In the case of converting chitin to chitosan, this reaction typically occurs under alkaline conditions, where chitin is treated with a strong base, such as sodium hydroxide. This process is essential for transforming the chitin dimer into a chitosan dimer by breaking the acetyl groups off the N-acetylglucosamine units.
Video consigliato:
05:09
Heck Reaction

Stability of Glycosidic Linkages

Glycosidic linkages, such as those found in chitin, can be sensitive to acidic conditions, leading to hydrolysis. The question notes that the glycosidic linkage is unstable in acid, which implies that any proposed reaction should avoid acidic conditions to prevent degradation of the polymer. Understanding the stability of these linkages is vital for successfully proposing a reaction that maintains the integrity of the chitin dimer during conversion to chitosan.
Video consigliato:
03:43
The radical stability trend.
Pratica correlata
Domanda del libro di testo

α-Pinene is a terpene found in pine trees. Starting from geranyl diphosphate (a terpene), draw the arrow-pushing mechanism to produce α-pinene. Assume that an enzyme active site will provide whatever acids and bases you might need.

1068
views
Domanda del libro di testo

(a) Suggest an arrow-pushing mechanism for the mutarotation of α-d-glucose to β-d-glucose in the presence of acid. Acid isn’t necessary, but it does increase the rate of the process.

(b) What is the role of acid in your mechanism?

1061
views
Domanda del libro di testo

The α- and β-anomers of glucose are shown here.

In solution, these two epimers can interconvert through a process called mutarotation. What is the ratio of anomers (α:β) when the specific rotation is +52.6°

979
views
Domanda del libro di testo

Is the compound d or l?

916
views