Ultrasound-assisted regio- and stereoselective synthesis of bis-[1′,4′-diaryl-1-oxo-spiro-benzosuberane-2,5′-pyrazoline] derivatives via 1,3-dipolar cycloaddition

The 1,3-dipolar cycloaddition reaction of the bis-hydrazonoyl chlorides with 2-arylidene-1-benzosuberone derivatives afforded the corresponding bis-[1',4'-diaryl-1-oxo-spiro-benzosuberane-2,5'-pyrazoline] derivatives. The reaction is carried out under ultrasonic irradiation as well as under conventional heating. The factors affecting the optimization of the cycloaddition reaction are examined in detail. X-ray crystallographic analysis was used in the establishment of the regio- and stereochemistry of the cycloaddition products.