Synthesis and crystal structures of N,N-diarylacetamides bearing two azulene rings

Intense absorption of azulene realized by molecular orbital inversion

“…The synthesis of 1 through the reaction between 1,3dibromoazulene 25 and diarylamine has previously been reported. 23 Although 1,3-dibromoazulene can be obtained by the reaction of azulene with N-bromosuccinimide (NBS), 25 a precursor of 2, 2,6-dibromoazulene, has been conventionally synthesised from a-tropolone in five steps (14% overall yield). 26,27 One of the factors that made the synthesis of 2 difficult is the complicated route of raw material synthesis.…”