How is 5-Methoxy-1,2,3,4-tetrahydroisoquinoline (CAS: 103030-70-2) typically synthesized?

5-Methoxy-1,2,3,4-tetrahydroisoquinoline is commonly synthesized by the methylation of 1,2,3,4-tetrahydroisoquinoline using methanol in the presence of a strong acid like hydrochloric acid. The reaction typically proceeds with high selectivity and moderate to good yield. Other methods include the reduction of 5-methoxymethylisoquinoline to form the desired tetrahydro derivative.