Synthesis of New Pseudo‐C‐Nucleosides Containing Pyrazole Rings in their Structure

Abstract

Synthetic approaches to new 4‐(furanos‐4‐C‐yl)‐1H‐pyrazole and 3‐(furanos‐4‐C‐yl)‐1H‐pyrazole derivatives are described, including its pyrazole‐5‐carboxylate derivative, which is a pyrazofurin analogue. Preparation of related 5‐acetoxy‐1‐acetyl‐1H‐pyrazole, 5‐acetoxy‐1H‐pyrazole‐1‐carboxylate, and 4,5‐dihydro‐1‐phenyl‐1H‐pyrazol‐5‐one derivatives is also reported. The formation of the pyrazole rings was accomplished either by reaction of enones and of 1,3‐diketones with N‐nucleophiles or by ring closure of a diazoketone.

Keywords:

• Pyrazoles
• Pseudo‐C‐Nucleosides
• 1,3‐Diketones
• Hydrazones