The synthesis of pentadienylium salts via reactions of (5-ethoxy-1,5-diaryl-2,4-pentadienylidene)ethyloxonium perchlorate with hydrazines

Article abstract of DOI:10.1016/S0040-4039(96)01508-0

Reaction of the readily available (5-ethoxy-1,5-diaryl-2,4-pentadienylidene)ethyloxonium perchlorate 1 with hydrazines, R₂NNH₂ or RNHNH₂, provides a simple and efficient synthesis of previously unknown (5-ethoxy-1,5-diaryl-2,4-pentadienylidene)hydrazinium salts 2a-d. Application of this method to the synthesis of the highly conjugated pentadienylium salt from terephthalic dihydrazide is reported.