Unexpected Synthesis of 1,3,4‐Oxadiazines using extraordinary effect of SBA‐Pr‐SO 3 H as the Nano–catalyst

Unexpected synthesis of 1,3,4‐oxadiazines has been accomplished through three‐component reaction of cyclohexyl isocyanide, hydrazide derivatives and cyclic ketones in the presence of a catalytic amount of SBA−Pr‐SO 3 H as an efficient catalyst. A range of spirooxadiazine derivatives were synthesized in high yields in a concise way. The same three‐component reaction in the presence of other acidic catalysts led to the synthesis of hydrazino amides. The formation of 1,3,4‐oxadiazines is related to the pore size and structure of SBA−Pr‐SO 3 H which spatial orientation of intermediate onto it leads to the formation of the oxadiazine ring.