Three-Component Synthesis of Tetrahydrobenzo[b]pyrans Catalyzed by Sodium Cyclamate

Abstract

The one-pot three-component cyclocondensation for the synthesis of tetrahydrobenzo [b]pyran derivatives in the presence of sodium cyclamate has been investigated. The three-component reaction was carried out in water medium under refluxing condition. Screening the reaction conditions revealed that 20 mol% sodium cyclamate refluxing water afforded the best results. Under green conditions, different substituted tetrahydrobenzo[b]pyrans were obtained from simple available starting materials, including malononitrile, functionalized benzaldehydes, and dimedone, via using an established efficient and straightforward approach.Multicomponent reactions (MCRs) involve at least three reactants that reacted in one-pot approach to synthesize valuable organic compounds and pharmacologically active molecules with high complexity and diversity as well as minimum side reactions. Green bond-forming, atomic and structural economy, step economy, high bond-forming index, avoidance of complicated purification processes and separation of intermediates, time-saving, mild conditions, environmental friendliness, elimination of waste production, energy-saving, and excellent functional group compatibility are the merits of MCRs. 1 In this reason, MCRs have been used for the synthesis of various heterocyclic compounds. 2 Tetrahydrobenzo[b]pyran derivatives are one of the biologically scaffolds owing to their applications in the synthetic and medicinal chemistry. 3 These important oxygen-containing heterocyclic compounds exhibit bioactivities, including anti-coagulant, 3 anti-anaphylactic, 3 calcium antagonist, 3 anticancer, 4 antibacterial, 5 anti-inflammatory, 6 lactamase inhibitor, 7 antifungal, 8 antioxidant, 8 anti-Huntington, anti-Alzheimer, anti-Schizophrenia, and anti-Parkinson. 3,9 The structures of some biologically active tetrahydrobenzo [b]pyrans are depicted in Figure 1. Besides, tetrahydrobenzo[b]pyrans were applied as starting materials to synthesize spirocyclopropylbarbiturates, 10 spirocyclopropylpyrazolones,

Synthesis and Evaluation of Acetylcholinesterase Inhibitory and Cytotoxic Activities of Pyrano[2,3-d]pyrimidines

“…Furthermore, numerous effective synthetic methods have been recorded for generating 2-amino-4H-pyran-3-carbonitrile intermediates. [53][54][55][56][57][58][59][60][61][62] Therefore, as part of our ongoing research focused on the discovery of novel bioactive compounds, [63][64][65][66][67] in this study, we focused on the synthesis and biological evaluation of novel pyrano[2,3-d ]pyrimidine compounds 8a-k. The newly synthesized molecules were evaluated for their AChE inhibitory activity, along with an evaluation of their cytotoxicity, to investigate their potential for use in treating AD.…”

A redox active organodiselenide as an efficacious catalyst for the synthesis of oxygen-containing heterocyclic compounds

“…19 Several methods have been reported for synthesizing tetrahydrobenzo[b]pyrans via a three-component condensation process with aryl aldehydes, dimedone, and malononitrile, using a variety of catalysts and under diverse reaction conditions. [20][21][22][23][24][25][26][27][28][29][30][31][32][33] Although some of these protocols are satisfactory, many suffer from drawbacks such as extended reaction times, complex work-up processes, and the use of expensive and hazardous catalysts. As a result, researchers are increasingly motivated to design and develop synthetic processes that are more environmentally benign and sustainable in light of the growing demand for a cleaner future.…”