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

作者：Kitabatake Michikazu; Hashimoto Aki; Saitoh Toshiaki; Sano Takehiro; Mohri Kunihiko; Horiguchi Yoshie^*

来源：Heterocycles, 2010, 81(8): 1903-1921.

DOI：10.3987/COM-10-11992

• 4,5,6,7-Tetrahydrothieno[3,2-c]pyridine
• Pictet-Spengler Reaction
• Formyliminium Ion
• Acid Catalyzed Cyclization
• One Pot Procedure

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.

• 出版日期2010-8-1