Engineering of indole-based tethered biheterocyclic alkaloid meridianin into β-carboline-derived tetracyclic polyheterocycles via amino functionalization/6-endo cationic π-cyclization

• Piyush K. Agarwal,
• Meena D. Dathi,
• Mohammad Saifuddin and
• Bijoy Kundu

Beilstein J. Org. Chem. 2012, 8, 1901–1908, doi:10.3762/bjoc.8.220

• developed for the construction of a functionalized natural product, meridianin, and its post conversion to pyrimido-β-carboline by cationic π- cyclization. The strategy involves the introduction of an amino group at the C-5 of the pyrimidine ring and utilizing the nucleophilictiy of the C-2 in the indole

• ring to facilitate cationic π-cyclization. Keywords: cyclization; indole; meridianin; natural products; nitrogen heterocycles; Introduction Indole is an important pharmacophore present in many natural and designed polyheterocyclic synthetic products of therapeutic importance [1][2][3]. The range of

• -based alkaloid meridianins into annulated indole-based polyheterocycles as novel chemprobes. For the synthesis of meridianin-inspired indole-based annulated polyheterocycles, we proposed to transform tethered biheterocycles into β-carboline-based polyheterocycles, a new prototype hitherto not reported