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Trimethoprim

Chemical Structure / Formula of Trimethoprim

  • Formula: C14H18N4O3

  • Structure: Pyrimidine derivative.

Chemical Structure of Trimethoprim

Mechanism of Action

  • Inhibits dihydrofolate reductase (DHFR), blocking bacterial DNA synthesis.

Uses

  • UTIs, respiratory tract infections (combined with sulfamethoxazole = Cotrimoxazole).

Side Effects

  • Megaloblastic anemia, hyperkalemia, GI upset.

Synthesis of Trimethoprim

Synthesis of Trimethoprim

Structure-Activity Relationship (SAR) of Trimethoprim

Structural Feature

SAR Insight

2,4-diaminopyrimidine ring

Essential for binding to dihydrofolate reductase (DHFR).

Substituted benzyl group

Increases selectivity for bacterial over human DHFR.

Electron-donating groups (methoxy)

Improve potency and enhance lipophilicity.

Bulky side chains

May hinder target binding or reduce specificity.


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