Analysis of aminoglycoside modification with addition of -OH and benzene ring
This is a work, and the author’s right to a work under international law comes into force from the moment the work is created.
The name of the new drug is Aminophenolazide
Author – Sukhachev Denis Pavlovich
1. Initial structure of the aminoglycoside (before changes)
Chemical structure:
- The basis of the molecule is an aminoglycoside ring containing several amino groups (-NH₂) and hydroxyl groups (-OH).
- This structure allows the molecule to interact with the 30S subunit of bacterial ribosomes, inhibiting protein synthesis.
- Sites that are targets for bacterial acetylation and phosphorylation enzymes are marked, which can lead to bacterial resistance.
Physical and chemical properties (subject to change):
- Hydrophilicity: High, which contributes to good solubility in water.
- Lipophilicity: Low, which limits permeability through cell membranes.
- Solubility: High in aqueous media, poor in organic solvents.
- Enzyme resistance: Relatively low, as many bacterial strains produce acetyltransferases that modify the aminoglycoside and render it inactive.
- Bioavailability: Good for intravenous and intramuscular administration, but poor for oral administration.
2. Modified structure of the aminoglycoside (after changes)
Changes have been made:
- Addition of a hydroxyl (-OH) group to O1
- This increases the hydrophilicity of the molecule.
- May affect interaction with bacterial ribosomes.
- It can protect the molecule from enzymatic degradation.
- Addition of a benzene ring to N1
- Changes the electronic configuration of a molecule.
- Makes the molecule more lipophilic, which can improve cell membrane penetration.
- It can protect the molecule from enzymatic degradation (bacterial acetyltransferases may not recognize this altered structure).
Physical and chemical properties (after changes):
- Hydrophilicity: Moderately decreases (due to the benzene ring), but the -OH group compensates for this effect.
- Lipophilicity: Increases due to the benzene ring, which can increase permeability through membranes.
- Solubility: The balance between solubility in water and in organic solvents.
- Enzyme resistance: Improved as modified sites may no longer be targets for bacterial acetyltransferases.
- Bioavailability: Potentially improved, especially for tissue penetration.
Expected changes in biological activity:
- The ability to bind to ribosomes may decrease, which may affect antibacterial activity.
- Membrane penetration may improve, which can be useful against Gram-negative bacteria.
- It may be effective against resistant strains of bacteria that have acetyltransferases.
3. How to achieve this modification in the laboratory?
3.1 Addition of -OH group to O1 (Hydroxylation)
Methods:
- Use of reagents for selective oxidation (e.g., reaction with sodium periodate NaIO₄).
- Or enzymatic introduction of a hydroxyl group using oxygenases.
Terms:
- Controlling the pH (~7-8) to avoid aminoglycoside degradation.
- The temperature is 25-40°C.
- An organic solvent can be used to selectively modify certain groups.
3.2 Addition of a benzene ring to N1 (Acylation or Alkylation)
Methods:
- Acylation (via amide bond)
- Use of benzoyl chloride (C₆H₅COCl) in the presence of a base (e.g., pyridine).
- A benzoyl-N1-substituted aminoglycoside is formed.
- Alkylation (through direct replacement of hydrogen with a benzyl group)
- The use of benzyl bromide (C₆H₅CH₂Br) in the presence of a weak base (NaHCO₃).
- A catalyst (Pd/C) can be used to form more stable bonds.
Terms:
- pH 8-10 (to avoid unwanted side effects).
- The temperature is ~50°C.
- Reaction time: 2-6 hours.
3.3 Cleaning and checking the modification
- Use of chromatography (HPLC) to confirm changes.
- NMR spectroscopy (nuclear magnetic resonance) to verify the structure.
- Testing of antibacterial activity on bacterial cultures.
4. 4. Conclusions and further research
What did we get?
- Increased lipophilicity → potentially better membrane penetration.
- Protection against bacterial enzymes → possible activity against resistant strains.
- Modified bioavailability → potentially changes in pharmacokinetics.
What do you need to check?
- Does the antibacterial activity remain after the changes?
- Does the new molecule cause toxic effects?
- Is it possible to scale up the synthesis in an industrial setting?
If you need to develop a more detailed laboratory protocol or test the effectiveness of a modified antibiotic on certain bacteria, I can help you with that! 🚀
