title: Mild and efficient cyanuric chloride catalyzed Pictet-Spengler reaction.
abstract: A practical, mild and efficient protocol for the Pictet-Spengler reaction catalyzed by cyanuric chloride (trichloro-1,3,5-triazine, TCT) is described. The 6-endo cyclization of tryptophan/tryptamine and modified Pictet-Spengler substrates with both electron-withdrawing and electron-donating aldehydes was carried out by using a catalytic amount of TCT (10 mol %) in DMSO under a nitrogen atmosphere. TCT catalyzed the Pictet-Spengler reaction involving electron-donating aldehydes in excellent yield. Thus, it has a distinct advantage over the existing methodologies where electron-donating aldehydes failed to undergo 6-endo cyclization. Our methodology provided broad substrate scope and diversity. This is indeed the first report of the use of TCT as a catalyst for the Pictet-Spengler reaction.
authors.affiliation: Department of Medicinal Chemistry, National Institute of Pharmaceutical Education and Research (NIPER)-Rae Bareli, ITI Compound, Rae Bareli-229010 (UP), India.
authors.forename: Ashish
authors.initials: A
authors.lastname: Sharma
authors.forename: Mrityunjay
authors.initials: M
authors.lastname: Singh
authors.forename: Nitya Nand
authors.initials: NN
authors.lastname: Rai
authors.forename: Devesh
authors.initials: D
authors.lastname: Sawant
keywords: 6-endo cyclization; Pictet–Spengler; TCT; cyanuric chloride; β-carboline