Polycyclic fused amidines. Part III. An unexpected mode of cyclisation of 2-phenacylisoquinolinium bromide

Abstract

Treatment of 2-phenacylisoquinolinium bromide with ammonium acetate in acetic acid gave 5,10-dihydro-2-phenylimidazo[1,2-b]isoquinoline (4) by cyclisation at the 3-position of the isoquinoline ring. The mechanism of this reaction is discussed. On similar treatment 1-phenacylquinolinium bromide gave 4,5-dihydro-2-phenyl-imidazo[1,2-a]quinoline (8).