Preparation of 1-dichloromethyl- and 1-trichloromethylisoquinolines by a one-step reaction of 1,2,4-triazines with 1,2-dehydrobenzene

An original and convenient procedure has been proposed for one-step preparation of 1-dichloromethyl- and 1-trichloromethylisoquinolines in up to 40% yields via aza-Diels–Alder reaction of the readily available 3-dichloromethyl- and 3-trichloromethyl-1,2,4-triazines (in the role of dienes) with 1,2-dehydrobenzene (in the role of in situ generated dienophile). The structure of 1-trichloromethyl-4-phenylisoquinoline was confirmed by X-ray structural analysis.