Synthesis of Isoquinoline

Synthesis of Isoquinoline covers Bischler–Napieralski, Pictet–Spengler, and Pomeranz–Fritsch routes with key steps for drug design.

1. Bischler–Napieralski Synthesis

   • Reactants: β-Phenylethylamine + acyl chloride → Cyclization
   • Reagents: POCl₃ or P₂O₅ (dehydrating agents)
   • Steps:
     1. Acylation of phenylethylamine
     2. Cyclization under acidic conditions
     3. Dehydrogenation → Isoquinoline

2. Pomeranz–Fritsch Reaction

   • Reactants: Benzaldehyde + aminoacetaldehyde diethyl acetal
   • Conditions: Acidic cyclization
   • Reaction:
     • • Benzaldehyde  +  H₂NCH₂CH(OEt)₂ →  Isoquinoline derivative
     • Useful for simple unsubstituted or mono-substituted isoquinolines

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