Niobium Pentachloride Mediated (Hetero)aromatic Aldehyde Friedel–Crafts Hydroxyalkylation with Arenes: An Efficient Strategy to Synthesize Triarylmethanes

Niobium pentachloride is an efficient and useful Lewis acid to conduct Friedel–Crafts hydroxyalkylation between arenes and (hetero)aromatic aldehydes, to generate triarylmethanes. This practical methodology offers several advantages, such as short reaction time, mild experimental conditions, and excellent yields.

A Facile Solvent-Free Route for One-Pot Multicomponent Synthesis of Benzylpyrazolyl Coumarins Derivatives in Presence of Effective Synergetic Catalytic System

A combinatorial library of benzylpyrazolyl coumarin derivatives have been synthesized by a green one-pot four-component reaction between aryl hydrazine/hydrazine hydrate (1), ethyl acetoacetate (2), aromatic aldehydes (3) and 4-hydroxycoumarin (4) catalyzed by niobium pentachloride with silver salt under solvent-free conditions has been developed. Experimental simplicity, simple work-up procedure and solvent-free reaction condition at room temperature are important features of the present protocol.

One-Step Synthesis of Methoxylated Phloroglucinol Derivatives Promoted by Niobium Pentachloride: An Experimental and Theoretical Approach

Phloroglucinol derivatives are an important class of natural compounds featuring the rhodomyrtone derivatives. In this work, the synthesis of compounds with a structure core of rhodomyrtosone I is described using a multicomponent reaction between aldehyde derivatives, dihydroresorcinol, and 3,5-dimethoxyphenol promoted by niobium pentachloride. This new method is simple, cost-effective, and provides a good yield. In addition, it can be conducted in good reaction times. Using Density Functional Theory (DFT) studies, bases are provided for a proposed reaction mechanism for the multicomponent reaction by exploring the energetics of proposed reactive intermediates and transition states.

Facile and efficient synthesis of xanthenedione derivatives promoted by niobium pentachloride

Xanthenedione derivatives were synthesised in one-pot reactions between arylaldehyde derivatives and 1, 3-cyclohexanedione promoted by niobium pentachloride. This new method is simple, cost-effective, high-yielding with a good variety of substrates generality, and can be conducted within reasonable reaction times.