【文章名】AN EFFICIENT AND CONVENIENT SYNTHESIS OF 4,5,6,7-TETRAHYDROTHIENO[3,2-c]PYRIDINES BY A MODIFIED PICTET-SPENGLER REACTION VIA A FORMYLIMINIUM ION INTERMEDIATE
AN EFFICIENT AND CONVENIENT SYNTHESIS OF 4,5,6,7-TETRAHYDROTHIENO[3,2-c]PYRIDINES BY A MODIFIED PICTET-SPENGLER REACTION VIA A FORMYLIMINIUM ION INTERMEDIATE
[摘要]：A synthesis of N-formyl-4,5,6,7-tetrahydrothieno[3,2-c]pyridines (5) was achieved in a highly efficient manner via trifluoroacetic acid catalyzed cyclization of formyliminium ion (4), which was produced by imination of 2-(2-thienyl)ethylamine (1) and a carbonyl compound (2) using titanium(IV) tetraisopropoxide followed by formylation with acetic-formic anhydride in a one-pot procedure. This modified Pictet-Spengler reaction provides a convenient method for preparing 4,5,6,7-tetahydrothieno[3,2-c]pyridines (6) possessing various substituents at C-4.
