Give equations for the formation and hydrogenolysis of N-benzyloxycarbonyl methionine.

Verified step by step guidance

1. Identify the structure of N-benzyloxycarbonyl methionine. This compound is a derivative of methionine where the amino group (-NH2) is protected by a benzyloxycarbonyl (Cbz) group. The general structure of the Cbz group is C6H5CH2OCO-.
2. Write the reaction for the formation of N-benzyloxycarbonyl methionine. This typically involves reacting methionine with benzyl chloroformate (C6H5CH2OCOCl) in the presence of a base (e.g., NaOH or NaHCO3) to neutralize the HCl byproduct. The reaction can be represented as: \( \text{H2N-CH(CH2CH2SCH3)-COOH} + \text{C6H5CH2OCOCl} \rightarrow \text{C6H5CH2OCO-NH-CH(CH2CH2SCH3)-COOH} + \text{HCl} \).
3. Explain the purpose of the benzyloxycarbonyl (Cbz) group. It is a protecting group used to temporarily block the amino group (-NH2) during chemical reactions to prevent unwanted side reactions. This is particularly useful in peptide synthesis.
4. Write the reaction for the hydrogenolysis of N-benzyloxycarbonyl methionine. Hydrogenolysis involves the removal of the Cbz group using hydrogen gas (H2) in the presence of a palladium catalyst (e.g., Pd/C). The reaction can be represented as: \( \text{C6H5CH2OCO-NH-CH(CH2CH2SCH3)-COOH} + \text{H2} \xrightarrow{\text{Pd/C}} \text{H2N-CH(CH2CH2SCH3)-COOH} + \text{C6H5CH3} + \text{CO2} \).
5. Summarize the overall process. The formation of N-benzyloxycarbonyl methionine involves protecting the amino group of methionine with a Cbz group using benzyl chloroformate. The hydrogenolysis step removes the Cbz group, regenerating the free amino group and producing toluene (C6H5CH3) and carbon dioxide (CO2) as byproducts.

Key Concepts

N-benzyloxycarbonyl (Z) Group

The N-benzyloxycarbonyl (Z) group is a protective group used in organic synthesis, particularly in peptide chemistry. It protects the amine group of amino acids during reactions, preventing unwanted side reactions. The Z group can be removed under specific conditions, allowing for the subsequent functionalization of the amino acid.

Hydrogenolysis

Hydrogenolysis is a chemical reaction that involves the cleavage of a bond by hydrogen in the presence of a catalyst, typically resulting in the removal of a protecting group. In the context of N-benzyloxycarbonyl methionine, hydrogenolysis would involve the reduction of the Z group to yield the free amino acid. This reaction is crucial for the synthesis of peptides and proteins.

Formation of N-benzyloxycarbonyl Methionine

The formation of N-benzyloxycarbonyl methionine involves the reaction of methionine with benzyloxycarbonyl chloride (Z-Cl) in the presence of a base. This reaction results in the attachment of the Z group to the amino group of methionine, creating a protected amino acid that can be used in peptide synthesis without interference from the amine.