Reactions of 3-acetyltropolone with benzaldehydes in trimethyl orthoformate in the presence of perchloric acid: Synthesis of 2-aryl-4- methoxy-9-oxocyclohepta[b]pyrylium perchlorates

Article abstract of DOI:10.1002/jhet.5570350632

3-Acetyltropolone (1) reacted with benzaldehydes in trimethyl orthoformate in the presence of perchloric acid to afford 2-aryl-4-methoxy- 9-oxocyclohepta[b]pyrylium perchlorates 3a-c in 25-37% yields. From the filtrates, 3-(3,4-diaryl-3-butenoyl)tropolones 4a,b and 3-(2- methoxycinnamoyl)tropolone (5) were also isolated.