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An efficient metal-free, one-pot protocol was developed for the synthesis of variety benzimidazole and quinazolinones in moderate to good yields. This protocol proceeds via oxidation of benzylamine, resulting in in-situ aldehyde formation followed by the condensation with o-phenylenediamine and o-aminobenzamide to the corresponding N-heterocycles using a mild oxidant phenyliodonium diacetate (PIDA). We describe a new strategy for C–N bond cleavage and formation in the absence of transition-metal reagent or ligand under environmentally benign reaction conditions.

A facile method for the synthesis of a variety of β-carbolines and their natural products such as norharmane (2a), harmane (2b), eudistomins I, N, T, and U (6, 7, 9 and 10, respectively) has been successfully developed via a decorboxylative aromatization tool by employing N-chlorosuccinimide (NCS) as a mild and efficient reagent. Gratifyingly, this reagent system proceeds in a one-pot manner and converted all the tetrahydro-β-carboline acids into their corresponding decorboxylative aromatic products with good to excellent yields. Additionally, this system works well in the case of tetrahydro-β-carboline esters to produce their aromatic partners in high yields.

Chiral pyrrolidinyl-oxazolecarboxamides are synthesized and used as organocatalysts in the asymmetric Michael addition of ketones with nitroalkenes under solvent-free conditions.

The cytotoxicity of the products was investigated with some of the compounds being effective in selected human cancer cell lines.