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Journal ArticleDOI

One-Pot Three-Component Synthesis of 3-Methyl-4-Arylmethylene- Isoxazol-5(4H)- Ones Catalyzed by Sodium Sulfide

31 Jan 2012-Phosphorus Sulfur and Silicon and The Related Elements (Taylor & Francis Group)-Vol. 187, Iss: 4, pp 448-453
TL;DR: In this paper, 3-Methyl-4-arylmethylene-isoxazol-5(4H)-ones were synthesized by the convenient three-component reaction of ethyl acetoacetate, hydroxylamine hydrochloride, and aromatic aldehydes catalyzed by sodium sulfide.
Abstract: 3-Methyl-4-arylmethylene-isoxazol-5(4H)-ones were synthesized by the convenient three-component reaction of ethyl acetoacetate, hydroxylamine hydrochloride, and aromatic aldehydes catalyzed by sodium sulfide in the presence of ethanol at room temperature. The advantages of this procedure were mild reaction conditions, high yields, short reaction time, and operational simplicity.
Citations
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Journal ArticleDOI
TL;DR: The one-pot three-component reaction of aryl aldehydes with hydroxylamine hydrochloride and ethyl 3-oxobutanoate/ethyl 4-chloro-3-oxide-polypropanoate in the presence of boric acid, H3BO3, in water leads to 4H-isoxazol-5(4H)-ones in high yields as mentioned in this paper.
Abstract: The one-pot three-component reaction of aryl aldehydes with hydroxylamine hydrochloride and ethyl 3-oxobutanoate/ethyl 4-chloro-3-oxobutanoate/ethyl 3-oxo-3-phenylpropanoate in the presence of boric acid, H3BO3, in water leads to 4H-isoxazol-5(4H)-ones in high yields. The merits of this method are efficiency, simplicity, clean, green, easy work-up, high yields, and shorter reaction times.

67 citations

Journal ArticleDOI
TL;DR: In this paper, it was found that the three-component tandem reaction enabled synthesis of pyran-annulated heterocycles in water at 50 ˚ C. The reaction is safe, uses mild conditions, and is environmentally benign.
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 three-component 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 α,β-unsaturated nitriles. The procedure is an easily performed, straightforward method for synthesis of a variety of pyran-annulated 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.

64 citations

Journal ArticleDOI
TL;DR: In this article, a highly efficient methodology for the synthesis of 3-methyl-4-arylmethylene-isoxazole-5(4H)-ones has been developed by visible light induced multicomponent reaction of aromatic aldehydes, ethyl acetoacetate, hydroxylamine hydrochloride, and sodium acetate in aqueous ethanol without any phase transfer catalyst or promoter.

61 citations

Journal ArticleDOI
TL;DR: In this article, the authors used the Citrus limon (lemon juice) as a natural and renewable catalyst for the green and environmentally friendly preparation of 3,4-disubstituted isoxazol-5(4H)-one derivatives and 6-amino-1,4dihydropyrano[2,3-c]-pyrazole-5-carbonitrile derivatives.
Abstract: Fruit juice of Citrus limon (lemon juice) has been utilized as a natural and renewable catalyst for the green and environmentally friendly preparation of 3,4-disubstituted isoxazol-5(4H)-one derivatives and 6-amino-1,4-dihydropyrano[2,3-c]-pyrazole-5-carbonitrile derivatives in hydroalcoholic media at 90 °C. A one-pot three-component reaction of β-oxoesters with hydroxylamine hydrochloride and various aromatic aldehydes afforded 3,4-disubstituted isoxazole-5(4H)-one derivatives in excellent yields. The rate constant (K = 6.12 × 10−2 min−1 at 25 °C) for the formation of isoxazole derivative (1g) was also calculated. Similarly, a four-component reaction of ethyl acetoacetate, hydrazine hydrate, aryl aldehydes, and malononitrile gives pyrano[2,3-c]-pyrazole derivatives in very good yields. After completion of the reaction, the products were isolated by simple filtration. A simple work-up process, high product yields, short reaction times, and the use of an inexpensive and biodegradable catalyst are the advanced rewards of the present protocol.

58 citations

Journal ArticleDOI
TL;DR: Potassium phthalimide (PPI) is employed as an efficient and effective basic organocatalyst for the one-pot three-component reaction of β-oxoesters with hydroxylamine hydrochloride and various aromatic aldehydes.

57 citations

References
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Journal ArticleDOI
TL;DR: MCRs and especially MCRs with isocyanides offer many opportunities to attain new reactions and basic structures, however, this requires that the chemist learns the "language" of M CRs, something that this review wishes to stimulate.
Abstract: Multicomponent reactions (MCRs) are fundamentally different from two-component reactions in several aspects. Among the MCRs, those with isocyanides have developed into popular organic-chemical reactions in the pharmaceutical industry for the preparation of compound libraries of low-molecular druglike compounds. With a small set of starting materials, very large libraries can be built up within a short time, which can then be used for research on medicinal substances. Due to the intensive research of the last few years, many new backbone types have become accessible. MCRs are also increasingly being employed in the total synthesis of natural products. MCRs and especially MCRs with isocyanides offer many opportunities to attain new reactions and basic structures. However, this requires that the chemist learns the “language” of MCRs, something that this review wishes to stimulate.

3,619 citations

Journal ArticleDOI
TL;DR: Multicomponent reactions (MCRs) provide a powerful tool towards the one-pot synthesis of diverse and complex compounds on the one hand and small and 'drug-like' heterocycles on the other hand.

444 citations

Journal ArticleDOI
TL;DR: The impressive speed combined with the unmatched control over reaction parameters justifies the growing interest in this application of microwave heating.

251 citations

Journal ArticleDOI
TL;DR: Most compounds exhibited potent and well-balanced antibacterial activity as well as high stability to DHP-I comparable to that of meropenem.

135 citations

Journal ArticleDOI
TL;DR: This method provides an efficient and much improved modification of the original Biginelli reaction in terms of high yields, and short reaction times, and has the ability to allow a wide variety of substitutions in all three components.

99 citations