Efficient tandem synthesis of a variety of pyran-annulated heterocycles, 3,4-disubstituted isoxazol-5(4H)-ones, and α,β-unsaturated nitriles catalyzed by potassium hydrogen phthalate in water

Abstract

A variety of 4H-chromenes, benzochromenes, 4,5-dihydropyrano[3,2-c]chromenes, 4H-pyran-3-carboxylates, and 3,4-disubstituted isoxazol-5(4H)-ones have been synthesized in high yields by using potassium hydrogen phthalate (KHP) as an inexpensive, commercially available catalyst. It was found that the threecomponent tandem reaction enabled synthesis of pyran-annulated heterocycles in water at 50°C. 3,4-Disubstituted isoxazol-5(4H)-ones were synthesized by use of 10 mol% KHP in water at room temperature. Also, treatment of methylene-containing compounds (malononitrile or ethyl cyanoacetate) with aromatic aldehydes in the presence of 5 mol% KHP resulted in a,b-unsaturated nitriles. The procedure is an easily performed, straightforward method for synthesis of a variety of pyranannulated compounds, isoxazol-5(4H)-one-containing heterocycles, and Knoevenagel adducts. The reaction is safe, uses mild conditions, and is environmentally benign. Other notable advantages are reuse of the catalyst, no use of hazardous organic solvents, and ease of work-up.

Synthesis of chromene derivatives in the presence of mordenite zeolite/MIL‐101 (Cr) metal–organic framework composite as catalyst

“…The composite consists of diffraction peaks from both MIL‐101 and MOR, indicating the presence of both phases in the composite material. In addition, the crystalline phases were well preserved after the addition of ED and HCl.On the basis of the information obtained from the above‐mentioned studies and the structure of (H‐MOR/MIL‐101‐ED), we anticipated that this reagent can be used as an efficient catalyst for the promotion of the reactions that need the use of an acidic or basic catalyst to speed up . Herein, we wish to extend the application of this catalyst for the synthesis of chromene derivatives via one‐pot condensation of aldehydes with resorcinol and malononitrile.…”

Recent Advance in Development of 3-Methyl-4-Arylmethylene Isoxazole-5(4h)-Ones and 6-Amino-1,4-Dihydropyrano[2,3-C]-Pyrazole-5-Carbonitriles: Synthetic Applications and Pathways

“…[40] www.wjpps.com water at room temperature (Scheme 11). [43] Various other solvents such as ethanol, 1,4-dioxane, hexane and acetone were also studied in this reaction by the authors, although best results were obtained in water in terms of product yield and reaction time.…”

A one‐pot green synthesis of 2‐amino‐4H‐benzo[h]chromenes catalyzed by a dioxomolybdenum Schiff base complex supported on magnetic nanoparticles as an efficient and recyclable nanocatalyst

“…Hence, the use of green solvents and heterogeneous reusable catalysts with economical, eco‐friendly, and efficient method represents one of the more powerful green chemical technology procedures. Hence, much effort has been devoted to the synthesis of 4 H ‐chromenes using different catalytic systems …”

“…Hence, much effort has been devoted to the synthesis of 4H-chromenes using different catalytic systems. [17][18][19][20][21][22][23] Because heterogeneous catalysts could be separated easily and reused, much attention is focused on development of these types of catalysts. [24] There has already been a vast literature about the usage of many supports for the heterogenization of homogeneous catalysts, such as organic polymers, [25] mesoporous silica, [26] and carbon-based compounds such as graphene oxide, [27] zeolites, [28] and so on.…”