Cephalosporin Antibiotics

What is crucial to the mechanism of b-lactam antibiotics?

What is important for binding in b-lactam antibiotics?

What is important for increasing ring strain in b-lactam antibiotics?

What is a possible modification of b-lactam antibiotics?

What is important to the mechanism of b-lactam antibiotics?

Why is cefalexin orally administered?

What is the significance of the methyl group at position 3 in cefalexin?

What is the role of the hydrophilic amino group in cefalexin?

What is the effect of the methyl group on the antibiotic's activity?

What is the significance of the side chain in cefalexin?

Cephalosporin Mechanism

The β-lactam ring is crucial to the mechanism of cephalosporins.
The carboxylic acid at position 4 is essential for effective binding.
The bicyclic system increases ring strain, contributing to the mechanism.
Stereochemistry plays a significant role in the mechanism of cephalosporins.
The acetoxy substituent is vital to the mechanism.

Possible Modifications

7-Acylamino side chain can be modified.
The 3-Acetoxymethyl side chain is another possible modification.
Substitution at C-7 is a potential modification.

Cefalexin Structure and Activity

The methyl group at position 3 is not a good leaving group.
The presence of a methyl group at position 3 compromises the activity of cefalexin.
However, the methyl group enhances oral absorption of cefalexin.

Cefalexin Administration

Cefalexin can be administered orally due to the presence of the methyl group.

Side Chain Features

The presence of a hydrophilic amino group at the alpha-carbon of the side chain helps to compensate for the loss of activity caused by the methyl group.
The hydrophilic amino group improves the activity of cefalexin despite the negative effect of the methyl group.

This quiz covers the structure and mechanism of cephalosporin antibiotics, including the importance of the b-lactam ring, carboxylic acid, and stereochemistry. It also explores possible modifications to the antibiotic structure.