2-(N'-aralkylidenehydrazino)adenosines: potent and selective coronary vasodilators

Area of Science:

• Medicinal Chemistry
• Cardiovascular Pharmacology
• Receptor Pharmacology

Background:

• Adenosine influences cardiac function through A1 and A2 receptors.
• A1 receptor activation causes negative dromotropic effects (slowed conduction).
• A2 receptor activation mediates coronary vasodilation.

Purpose of the Study:

• To synthesize and evaluate 2-(N'-aralkylidenehydrazino)adenosine analogues.
• To assess the potential of these compounds as selective coronary vasodilators.
• To investigate their activity at adenosine receptors in cardiac tissue.

Main Methods:

• Synthesis of 2-(N'-aralkylidenehydrazino)adenosine analogues via condensation reactions.
• Bioassays using guinea pig heart Langendorff preparations.
• Measurement of negative dromotropic effects and coronary vasodilation.
• Assessment of selectivity using adenosine receptor antagonists.

Main Results:

• Synthesized analogues 2-27 in good yields.
• Analogues showed weak negative dromotropic activity (EC50 ~0.8 µM).
• Several analogues, including 2-(N'-benzylidenehydrazino)adenosine derivatives, exhibited potent coronary vasodilation (EC50 1.7-3.2 nM).
• High selectivity ratios (up to 43,000) for coronary vasodilation over negative dromotropic effects were observed.
• Receptor-mediated activity confirmed by antagonist studies.

Conclusions:

• 2-(N'-aralkylidenehydrazino)adenosine analogues are potent and selective coronary vasodilators.
• These compounds primarily act via A2 receptors.
• They represent promising candidates for developing novel cardiovascular therapeutics.