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

Abstract

An efficient, rapid, one-pot synthesis of tetrahydrobenzo[b]pyran is achieved via a three-component reaction of aldehydes, 1,3-diketone, malononitrile in 20% ethanol using anhydrous potassium phosphate as a catalyst at room temperature. The key advantages are the short reaction time, high yields, simple work-up, inexpensive catalyst and purification of products by non-chromatographic methods, i.e. by simple recrystallization from ethanol.

Mg(Clo4)2 as A Recyclable Catalyst for Synthesis of 4H-Chromenes

“…At the start of this investigation, the one-pot three component reaction of benzaldehyde 1a, malononitrile 2 and dimedon 3 (1 mmol each) in ethanol was employed as a model reaction. The use of different amounts of catalyst (10,20,25, and 30W %) at different temperature was investigated. The best result was obtained with 25W% of starch solution at 100°C (Tables 1, Enter 11).…”

Synthesis of pyran annulated heterocyclic scaffolds: a highly convenient protocol using dimethylamine

“…Very interestingly, 4H-pyrans can be converted into pyridine analogues, which are related to the calcium antagonists of the dihydropyridines [15,16]. Due to the wide applications of the pyran nucleus, a number of synthetic methods have been reported with catalysts like, DMAP [17], K 3 PO 4 [18], CaCl 2 [19], piperazine [20], NH 2 -SiO 2 [21], SBSSA [22], lactose [23], etc., many of them suffered from any one of the demerits such as, prolonged reaction times, expensive catalysts, low yields, and harsh reaction conditions. Hence, still there is a need for the development of alternate high-yielding newer methodologies using very inexpensive catalysts under mild reaction conditions.…”

Ru(II) complexes bearing tertiary phosphine ligands: a novel and efficient homogeneous catalyst for one‐pot synthesis of dihydropyrano[3,2‐c]chromene and tetrahydrobenzo[b]pyran derivatives

“…[1] Several synthesis methods for the preparation of these heterocyclic compounds have been reported in the presence of different catalysts such as diammonium hydrogen phosphate, [2] K 2 CO 3 under microwave irradiation, [3] tetrabutylammonium bromide (TBAB), [4] ion liquids, [5,6] heteropolyacids, [7] hexamethylenetetramine, [8] KF/Al 2 O 3 , [9] sodium dodecyl sulfate (SDS), [10] 1,8-diazabicyclo [5.4.0] undec-7-ene (DBU), [11] trisodium citrate, [12] high surface area MgO, [13] K 3 PO 4 , [14] Na 2 SeO 4 , [15] NaBr, [16] sulfonic acid functionalized silica, [17] hexadecyldimethylbenzyl ammonium bromide (HDMBAB), [18] (S)-proline, [19] or by electrochemical reactions. [20] However, each of the above procedures has its own disadvantages such as long reaction time, low yield, tedious workup and so forth.…”