637040-73-4

Upstream product

• 261729-91-3 (1R)-1-methyl-N-[(R)-1-phenylethyl]-2-phenylsulfanylethylamine 
• 261729-95-7 N-[(R)-1-methyl-2-phenylsulfanylethyl]-N-[(R)-1-phenylethyl]formamide 
• 3886-69-9 (R)-1-phenyl-ethyl-amine 
• 261729-99-1 N-[(1R)-1-methyl-2-(phenylsulfinyl)ethyl]-N-[(1R)-1-phenylethyl]formamide 
• 71-43-2 benzene 

Relevant academic research and scientific papers

Super acid-induced pummerer-type cyclization reaction: Improvement in the synthesis of chiral 1,3-dimethyl-1,2,3,4-tetrahydroisoquinolines

Improved synthesis of four stereoisomeric chiral 1,3-dimethyl-1,2,3,4- tetrahydroisoquinolines (1a, b, ent-1a, b) was achieved via the super acid-induced cyclization of chiral N-[1-methyl-2-(phenylsulfinyl)ethyl]-N-(1- phenylethyl)formamides (4a, b, ent-4a, b) using the Pummerer-type cyclization reaction as a key step. The cyclization leading to the isoquinoline ring proceeded in a quantitative manner when trifluoromethane sulfonic acid (TFSA) was used as the super acid, although Friedel-Crafts-type alkylation of 4-phenylsulfanyl TIQ derivatives (5) with benzene used as the solvent accompanied cyclization to yield the 4-phenyl-TIQs (7). The byproduct (7) was exclusively formed when a large excess amount of TFSA was used.