191545-92-3Relevant articles and documents
An improved synthesis of 1,2,3,4-tetrahydroisoquinolines via intramolecular cyclization of N-acyl-N-(aryl)methyl-2- (phenylsulfinyl)ethylamine by Pummerer reaction
Shinohara, Tatsumi,Toda, Jun,Sano, Takehiro
, p. 813 - 819 (2007/10/03)
Pummerer reaction of the sulfoxides 5 of N-acyl-N-(aryl)methyl-2- (phenylthio)ethylamines (4) on treatment with trifluoroacetic anhydride (TFAA) effectively caused intramolecular cyclization under a mild condition to give N-acyl-4-phenylthin-1,2,3,4-tetrahydroisoquinolines (TIQs) (7). The reaction of the N-formyl sulfoxide 5c without a methoxy group in the benzene ring using a formyl group for N-protection is particularly efficient. Treatment of the N-formyl sulfoxide 5f with TFAA did not give away TIQ, but a sequential treatment using TFAA and BF3·Et2O afforded N-formyl-4- phenylthio-TIQ (7f) in quantitative yield. The efficiency of this method or preparing TIQs was demonstrated in the synthesis of 1,4-dideuterio-TQ (10D) and its N-methyl derivative (11D).