Tandem and Stepwise Reactions of β-(3,4-Dialkoxyphenyl)ethylamine Bis(aminol) Ethers in Syntheses of N-Arylmethyl-6,7-dimethoxy-1,2,3,4-tetrahydroisoquinolines: A Synthesis of Sendaverine Methyl Ether - Cooper, Mark S; Earle, Martyn J; Fairhurst, Robin A; Heaney, Harry; Papageorgiou, George; Wilkins, Robert F (Synlett, 1990)