Environmentally benign reactions are of primary concern and have become the major targets of the organic chemists. The development of the concept and green chemistry and it 12 principles acts as guidelines to design the products and processes that reduce and eliminate the use and generation of hazardous substances. Catalysis plays a major role1c and the development of alternate pathways is of primary interest. In this process, replacement of organic solvents with inexpensive, safe and nontoxic solvents e.g., water constitute one of the main features of green chemistry.

A simple evaluation of Lewis acids revealed that Α-hydrazonyl chlorides undergo [2+3] cycloadditions reaction with activated olefins to form the cycloaddition products. The Α-hydrazonyl chlorides in presence of Lewis acids generate nitrile imines in situ which react with dipolarphiles to afford the cycloaddition products. The LiNO3, Cu(NO3)2, Cu(SO)4.5H2O, Ag2CO3, NiNO3, Ce(NO3)2-catalyzed 1,3-dipolar reactions led to the synthesis of respective pyrazoline compounds and the results create new possibilities for exploiting the metal salt-catalyzed cycloaddition reaction and facile synthesis of five membered heterocycles. In addition to these the role of tetrahexylammonium chloride related to a kind micellar catalysis in cycloaddition reactions is also examined.

We thank the National Institutes of Health (G12RR13459) and the National Science Foundation (HRD-0401730) for their generous financial support.