4,4′-Trimethylenedipiperidine (TMDP): An Efficient Organocatalyst for the Mechanosynthesis of Pyrano[4,3-b]pyrans under Solid-state Conditions

Abstract

This paper presents a green protocol for the synthesis of pyrano[4,3-b]pyrans using a catalytic amount of 4,4′-trimethylenedipiperidine (TMDP) as a novel, efficient and recyclable organocatalyst through ball milling process at room temperature. The essential part of this protocol is a Knoevenagel condensation and to the best of our knowledge, this is the first report that exhibits the catalytic efficiency 4,4′-TMDP for the one-pot multicomponent reaction under melt-state conditions. The scope of the present protocol was explored and demonstrated for the synthesis of pyrano[4,3-b]pyrans in an environment-friendly protocol. The several interesting features of the present methodology are including a cost-effectiveness procedure, good to excellent yield of the desired products, high reaction rate, a broad substrate-scope, and recyclability of organocatalyst; as well as the 4,4′-TMDP is a nontoxic, inexpensive, and commercially available catalyst. Furthermore, this efficient methodology displays a combination of the synthetic virtues of conventional multicomponent reaction with ecological benefits and convenience of a facile mechanochemical process.

Keywords:

• Ball mill process
• environmental benign conditions
• melt-state synthesis
• one-pot multicomponent reaction
• 4,4′-trimethylenedipiperidine

Acknowledgments

The authors are grateful to staff members in the Analytical and Testing Center of the University of Malaya for partial support.

Disclosure statement

No potential conflict of interest was reported by the authors.