Formation of Imidazopyridines by the Phase Transfer Catalyzed Reaction of α-(Aminomethyl)pyridines with CHCl3 and Alkaline Hydroxide

Article abstract of DOI:10.1021/jo00007a028

The reaction of chloroform with 2-(aminomethyl)pyridine (1) under basic phase-transfer catalysis affords the highly fluorescent imidazo<1,5-a>pyridine (2) in 25percent isolated yield.Despite the formation of considerable tarry residue, GC-MS indicates that the volatile fraction of the reaction is simple and consists of 2 and two minor components identified as N-(2-pyridylmethyl)formamide (6) and (2-pyridylmethyl)isonitrile (7).The basic phase transfer catalyzed reaction of chloroform with a series of α-(aminomethyl)azanaphthalenes was found to be general and yield the corresponding annulated imidazo derivatives in comparable yields.Despite product yields in the 25percent range, GC of the reaction mixtures indicates that the volatile fractions generally consist of residual starting aminomethyl compound, the imidazo product, and a minor amount of the (α-azanaphthylmethyl)formamide.However, 3-(aminomethyl)isoquinoline (18) failed to provide any of the expected imidazo<1,5-a>isoquinoline (19).The failure to detect 19 was investigated.