A Convenient 1,3-Dipolar Cycloaddition Reaction for the Synthesis of Spirooxindoles and Some Other Spirocompounds Containing the 1,3,4-Oxadiazole Moiety.

A series of spiro[indoline-3,2′-[1,3,4]oxadiazol]-2-ones were prepared from the reaction of isatin derivatives and hydrazonoyl chlorides through the 1,3-dipolar cycloaddition reaction. This method has some important aspects, such as mild reaction condition, easy purification, and high yield of products. Also, the synthesis of spiro[acenaphthylene-1,2′-[1,3,4]oxadiazol]-2-one and spiro[[1,3,4]oxadiazole-2,9′-phenanthren]-10′-one were studied under the same condition. The structures were confirmed spectroscopically (IR, ¹H- and ¹³C-NMR, and EI-MS) and by elemental analyses. A plausible mechanism for this reaction is proposed. [ABSTRACT FROM AUTHOR]