Tetrahedron

Synthesis of tetrahydro-5-azaindoles and 5-azaindoles using Pictet–Spengler reaction—appreciable difference in products using different acid catalysts

AMA Shumaila, VG Puranik, RS Kusurkar

Index: Shumaila, Abdullah M.A.; Puranik, Vedavati G.; Kusurkar, Radhika S. Tetrahedron, 2011 , vol. 67, # 5 p. 936 - 942

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Citation Number: 11

Abstract

Pictet–Spengler condensation of 2-(aryl)-2-(1H-pyrrol-2-yl) ethanamines using conventional acid catalysts like TMSCl or TFA resulted in the formation of substituted 5-azaindoles involving a tandem one pot four steps reaction sequence. By contrast use of glacial acetic acid furnished the targeted tetrahydro-5-azaindoles in diastereoselective manner. These were readily dehydrogenated to 5-azaindoles.