Azo compounds isomerization

A cyclic silyl hydrazone derivative <83ZAAC(50i)57> as well as azo compounds isomeric to hydrazones <74PS197> have also been used for the synthesis of 2//-1,2,3-diazaphospholes by the PCI3 condensation. 2,4,5-Triphenyl-l,2,3-diazaphosphole is best prepared from the respective azoalkene and a fused benzothiadiphosphole as phosphorus donating reagent <95TL447>. 

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