Uncatalyzed Reactions in Aqueous Media: Three-Component, One-Pot, Clean Synthesis of Tetrahydrobenzo[b]pyran Derivatives

Abstract

The synthesis of various tetrahydrobenzo[b]pyran derivatives has been carried out by means of an uncatalyzed, three-component, one-pot clean condensation of aromatic aldehydes, reactive methylene compounds, and dimidone in aqueous medium. Simple workup, and mild and neutral conditions that give quantitative yields of products in pure form, are the attractive features of this method.

Al Atom Activation of C–S Bonds: Characterization of the Aluminathietane Formed in the Reaction of Al Atoms with 1,2-Butylene Sulfide

“…The NMR parameters are in agreement with those found in the literature. 31 Synthesis of Deuterated 1,2-BuS. 1,2-BuS-1,1-d 2 and 1,2-BuS-2-d 1 were synthesized from the corresponding oxides, i.e., 1,2-butylene oxide-1,1-d 2 and 1,2-butylene oxide-2-d 1 .…”

Potassium Phosphate Catalyzed a Rapid Three-Component Synthesis of Tetrahydrobenzo[b]pyran at Ambient Temperature

“…A detailed literature survey towards the multicomponent synthesis of tetrahydrobenzo[b]pyran revealed that most of the protocols employed for this reaction operate under high thermal activation [14][15][16][17][18][19], microwave activation [15,20,21] and ultrasonic irradiation [22,23]. Recently, Fotouhi et al [24] reported electrochemical synthesis of tetrahydrobenzo[b]pyran.…”

“…In addition, the tetrahydrobenzo[b]pyran nucleus is an important structural motif of a series of natural products [8,9] and can be converted into pyridine systems which relate to pharmacologically important calcium antagonists of the dihydropyridine(DHP) [10,11] type. The importance of these compounds has led the scientific community to synthesize them using the bicomponent condensation [12,13] of dimedone with a-cyanocinnamonitriles or multicomponent condensation [14][15][16][17][18][19] of dimedone with aromatic aldehydes and malononitrile.…”

[Fe3O4@SiO2@(CH2)3im]C6F5O as a New Hydrophilic and Task‐Specific Nanomagnetic Catalyst: Application for Synthesis of β‐Azido Alcohols and Thiiranes under Mild and Green Conditions

“…Also, epoxides can be converted to thiiranes in reaction with different sulfur donor reagents such as thiourea, dimethylthioformamide, inorganic thiocyanates, phosphine sulfide and 3‐methylbenzothiazol‐2‐thione . Often these reactions take place in the presence of various acidic or basic catalysts . Thiiranes as important precursors have been also used for various purposes …”