Isoxazoles are important five-membered aromatic heterocycles in organic chemistry. Recently, many exciting advances in the synthesis and functionalization of isoxazoles have been reported. New transition metal-catalyzed reactions have resulted in the development of attractive and highly efficient synthetic approaches to densely functionalized isoxazoles. Complete control of regioselectivity can be achieved on the basis of a judicious choice of metal catalyst and reaction partners using dipolar cycloaddition and cycloisomerization reactions, while more recent studies have focused on the site-selective functionalization of isoxazoles via CH functionalization. New strategies for the use of isoxazoles as scaffolding templates in asymmetric synthesis have emerged, thus opening new prospects for the synthesis of enantioenriched motifs under the conditions that are orthogonal to other transformations. In this review, recent advances involving the synthesis and reactivity of isoxazoles are summarized. The review covers the period from January 2005 to June 2015.

Recent Developments in the Synthesis and Reactivity of Isoxazoles: Metal Catalysis and Beyond

4-Thiazolidinones: the advances continue….

Mannich bases in medicinal chemistry and drug design.

The molecular structures and spectral properties of α-haloketones as well as their syntheses are analyzed and reviewed. Their reactivity towards oxygen, nitrogen, and sulfur nucleophiles, carboxylic acids, carbon nucleophiles, alkenes, and alkynes are discussed.

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The Chemistry of α-Haloketones and Their Utility in Heterocyclic Synthesis

Amino acids and amines have been used to catalyze three component hetero-domino Knoevenagel/Diels−Alder/epimerization reactions of readily available various precursor enones (1a−l), aldehydes (2a−p), and 1,3-indandione (3). The reaction provided excellent yields of highly substituted, symmetrical and nonsymmetrical spiro[cyclohexane-1,2‘-indan]-1‘,3‘,4-triones (5) in a highly diastereoselective fashion with low to moderate enantioselectivity. The Knoevenagel condensation of arylaldehydes (2a−p) and 1,3-indandione (3) under organocatalysis provided arylidene-1,3-indandiones (17) in very good yields. We demonstrate for the first time amino acid- and amine-catalyzed epimerization reactions of trans-spiranes (6) to cis-spiranes (5). The mechanism of conversion of trans-spiranes (6) to cis-spiranes 5 was shown to proceed through a retro-Michael/Michael reaction rather than deprotonation/reprotonation by isolation of the morpholine enamine intermediate of cis-spirane (22). Prochiral cis-spiranes (5ab) and trans...

https://www.scripps.edu/barbas/pdf/RamcharyJOC04.pdf

Direct organocatalytic asymmetric heterodomino reactions: the Knoevenagel/Diels-Alder/epimerization sequence for the highly diastereoselective synthesis of symmetrical and nonsymmetrical synthons of benzoannelated centropolyquinanes.

Claisen condensation. Behaviour of esters towards 3-acetyl-1,2,3,4-tetrahydro-2,4-dioxo-1-phenylquinoline

Synthesis and Characterization via Molecular Quantum Parameters of 2H-Thiazolo[3,2-a]pyrimidine-3,5,7(6H)-trione

This review article includes a recent development in the chemistry of 4-thiazolidinones. Structure, basicity, synthetic aspects, reactions, and applications were also reported.

Progress in the Chemistry of 4-Thiazolidinones

Thiazolidin-4-one derivative 3 was synthesized by the transformation of chloroacetamide derivative 2 with NH4SCN.The condensation of 3 with p-anisaldehyde afforded the corresponding arylidene derivative 4. Also, the alkylation of chloroacetamide derivative 2 with different heterocyclic compounds was investigated. Annulation of 5-amino-3-methylisoxazole (1) with α-halocarbonyl compounds 12 and 14 furnished pyrrolo[3,2-d]isoxazole and isoxazolo[5,4-b]azepin-6-one derivatives 13 and 15, respectively, while reaction of 1 with 1-chloro-4-(chloromethyl)benzene gave the monoalkylated product 17. The newly synthesized compounds were screened for their antitumor activity, and the geometry optimizations are in a good agreement with the experimentally observed data.

Synthesis, DFT Study, and Antitumor Activity of Some New Heterocyclic Compounds Incorporating Isoxazole Moiety

Condensation of 4-bromomethylquinoline derivatives1 a-1 c with glycine and thioglycolic acid gave the corresponding quinolylmethylglycine and quinolylmethylthioacetic acid derivatives2 a-2 c and2 d-2 f, respectively. Cyclization of2 a-2 f was affected either by polyphosphoric acid or concentrated sulphuric acid to give3 a-3 f. Chlorination of2 a-2 f and3 a-3 f were also accomplished.

Hanafi H. Zoorob

Papers

Claisen condensation. Behaviour of esters towards 3-acetyl-1,2,3,4-tetrahydro-2,4-dioxo-1-phenylquinoline

Synthesis and Characterization via Molecular Quantum Parameters of 2H-Thiazolo[3,2-a]pyrimidine-3,5,7(6H)-trione

Progress in the Chemistry of 4-Thiazolidinones

Synthesis, DFT Study, and Antitumor Activity of Some New Heterocyclic Compounds Incorporating Isoxazole Moiety

Reactivity of 4-bromomethylquinoline derivatives towards glycine and thioglycolic acid. A new ring system