First successful synthesis, isolation and characterization of open-chain 1,2-diazidoethenes

Open-chain 1,2-diazidoethenes have been obtained from the recently reported acceptor-substituted propargyl azides by one-pot reactions with tetramethylguanidinium azide (TMGA) and in some cases via a two-step procedure starting with in situ production of the corresponding azidoallene followed by addition of hydrazoic acid with the help of TMGA. In a different synthetic pathway, the substitution reactions between 2-azido-3-haloacroleins and hexadecyltributylphosphonium azide (QN3) have been used. In order to have more evidence for their structures, some diazido compounds were converted to their bis-triazole derivatives through 1,3-dipolar cycloaddition.