Zeofen as a Catalyst for Cleavage of Semicarbazones and Phenyl Hydrazones Under Conventional Heating and Microwave Irradiation

Protection and deprotection of a functional group is almost inevitable in multistage organic synthesis'. Carbonyl compound derivatives such as phenylhydrazones and semicarbazones are important masked compounds of carbonyl groups'. Semicarbazones and phenylhydrazones are highly crystalline and are used for the characterization and purification of carbonyl compounds'. Regeneration of carbonyl compound from prepared semicarbazones and phenylhydrazones has received a significant attention in recent years' within the framework of Green chemistry(5), a noticeable improvement provided by the association of solvent free techniques and microwave activation(6). The combination of solvent free reaction conditions and microwave irradiation leads to large reduction in reaction times, enhancements conversions and sometimes in selectivity with several advantages of the eco-friendly approached termed green chemistry. In preceding papers we introduced zeofen as a catalyst for the selective oxidation of alcohols under classical heating and microwave irradiation under solvent free conditions(7), oxidative cleavage of THP ethers in non-aqueous conditions(7), oxidative deprotection of TMS ethers under microwave irradiation in solventless system(9) and as an eco-friendly catalyst for deoximation(10). In this communication we wish to report that zeofen is an excellent and efficient reagent for the oxidative cleavage of semicarbazones 1a-8a and phenylhydrazones 1b-8b to the corresponding compounds 2a-8a under classical heating and microwave irradiation.