Book ChapterDOI
Chapter 1 Dimedone: A Versatile Precursor for Annulated Heterocycles
El Sayed H. El Ashry,El Sayed H. El Ashry,Laila F. Awad,Yeldez El Kilany,El-Sayed I. Ibrahim +4 more
TLDR
The chapter illustrates that dimedone's structural features and its reactivity to form more functionalized derivatives have led to the construction of a wide range of fused or spiral biheterocycles.Abstract:
Publisher Summary This chapter explores that dimedone is a versatile precursor for annulated heterocycles. Dimedone(1) is an alicyclic compound having 1,3-dicarbonyl groups flanked by a methylene group and exists in a tautomeric transenolized form where intramolecular hydrogen bonding is not possible. Dimedone is an excellent precursor for partially hydrogenated fused heterocycles where two of the carbon atoms of dimedone are part of the backbone of the formed heterocycles. The chapter illustrates that dimedone's structural features and its reactivity to form more functionalized derivatives have led to the construction of a wide range of fused or spiral biheterocycles. Finally, this chapter emphasizes the role of 1 in the synthesis of fused heterocycles, classified according to the size of the ring and the number of heteroatoms in the heterocycle fused to the cyclohexane ring and subdivided according to the heteroatoms and their arrangement in the ring.read more
Citations
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Journal ArticleDOI
Tandem Aldol-Michael reactions in aqueous diethylamine medium: a greener and efficient approach to dimedone-barbituric acid derivatives
Assem Barakat,Assem Barakat,Abdullah Mohammed Al-Majid,Abdulaziz Moshabab Al-Ghamdi,Yahia N. Mabkhot,Mohammed Rafiq H. Siddiqui,Hazem A. Ghabbour,Hoong-Kun Fun +7 more
TL;DR: An environmentally benign Aldol-Michael protocol for the synthesis of dimedone-barbituric derivatives using aqueous diethylamine medium is achieved.
Journal ArticleDOI
Tandem Knoevenagel–Michael reactions in aqueous diethylamine medium: A greener and efficient approach toward bis-dimedone derivatives
Abdullah Mohammed Al-Majid,Mohammad Shahidul Islam,Assem Barakat,Assem Barakat,Nasser J. Al-Qahtani,Sammer Yousuf,M. Iqbal Choudhary,M. Iqbal Choudhary +7 more
TL;DR: In this article, Diethylamine catalyzed tandem Knoevenagel-Michael reactions have been carried out in aqueous medium as an efficient, greener and cost effective process for the simple one-pot synthesis of bis-dimedone derivatives.
Journal ArticleDOI
Catalyst-Free Synthesis of Xanthene and Pyrimidine-Fused Heterocyclic Derivatives at Water-Ethanol Medium and Their Antioxidant Properties
Journal ArticleDOI
Six-Membered Ring Systems: With O and/or S Atoms
John D. Hepworth,B. Mark Heron +1 more
TL;DR: In this article, a review of reaction chemistry and new ring synthetic methods for pyranones is presented, which covers work published in the calendar year 2010 and includes new ring synthesis methods for trioxanes, tetraoxane, dioxanes, trithianes and oxathianes.
Journal ArticleDOI
Intramolecular interactions in dimedone and phenalen-1,3-dione adducts of 2(4)-pyridinecarboxaldehyde: Enol-enol and ring-chain tautomerism, strong hydrogen bonding, zwitterions
Mark Sigalov,Bagrat A. Shainyan,Pnina Krief,Igor A. Ushakov,Nina N. Chipanina,Larisa P. Oznobikhina +5 more
TL;DR: The 2:1 adducts of dimedone and phenalen-1,3-dione with 2-and 4-pyridine carboxaldehyde, in spite of similar chemical behavior of their diketone precursors, have quite different tautomeric structure both in solid state and in solution as discussed by the authors.
References
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Journal ArticleDOI
Facile Yb(OTf)3 promoted one-pot synthesis of polyhydroquinoline derivatives through Hantzsch reaction
TL;DR: In this article, a simple and environmentally benign Hantzsch reaction for polyhydroquinoline derivatives is described. But the process is operationally simple, environmentally benign and has excellent yield.
Journal ArticleDOI
Molecular iodine-catalyzed one-pot synthesis of 4-substituted-1,4- dihydropyridine derivatives via Hantzsch reaction
TL;DR: In this paper, a simple, inexpensive and efficient one-pot synthesis of 1,4-dihydropyridine derivatives at room temperature using catalytic amount of iodine was reported with excellent product yields.
Journal ArticleDOI
Solvent-free Knoevenagel condensations and Michael additions in the solid state and in the melt with quantitative yield
TL;DR: In this article, several Knoevenagel condensations of solid or liquid aromatic aldehydes are performed with four barbituric acids, Meldrum's acid, dimedone, cyanoacetamide, malodinitrile and methyl cyano-acetate.
Journal ArticleDOI
Amberlyst-15: An efficient reusable heterogeneous catalyst for the synthesis of 1,8-dioxo-octahydroxanthenes and 1,8-dioxo-decahydroacridines
TL;DR: Amberlyst-15 has been found to be an efficient catalyst for the synthesis of 1,8-dioxo-decahydroacridines in excellent yields as mentioned in this paper.
Journal ArticleDOI
HClO4–SiO2 and PPA–SiO2 catalyzed efficient one-pot Knoevenagel condensation, Michael addition and cyclo-dehydration of dimedone and aldehydes in acetonitrile, aqueous and solvent free conditions: Scope and limitations
TL;DR: In this article, the scope and limitations of the two catalysts in various reaction conditions examined were described, and both HClO4−SiO2 and PPA-SiO 2 catalysts yielded only 4 as the product in aqueous medium.