Cyclohexanone → p-Toluenesulfonic acid

Participants

Reaction Steps

A solution of 2-aminobenzonitrile in xylenes with 0.02-0.05 equiv of p-toluenesulfonic acid monohydrate is heated to reflux with stirring. At reflux, cyclohexanone in xylenes is added. The mixture is refluxed for 8 to 12 hours, cooled and another 1.0-1.5 equiv of p-toluenesulfonic acid monohydrate is added. The mixture is heated to reflux for 3 to 7 hours. The product, as a p-toluenesulfonic acid salt, is isolated by filtration. Basification of this product with aqueous sodium hydroxide and extraction with dichloromethane provide the desired product, tacrine, as a free base.

Provenance & Evidence