1,2,3,4-Tetrahydroisoquinoline derivatives were synthesized from 2-(3-methoxyphenyl)ethy- lamine and ethyl chloroformate via the process of nucleophilic substitution, cyclization reaction and lithium aluminium hydride (LAH) reduction. The key step, cyclization reaction, was accomplished by using polyphoshponic acid (PPA) as a catalyst conveniently and effectively without any another catalyst for the first time. Moreover, a series of isoquinolone derivatives were synthesized.

Key words: 1,2,3,4-tetrahydroisoquinoline, cyclization reaction, polyphoshponic acid (PPA)