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In this work, we prepared successfully a recoverable heterogeneous magnetic nano-catalyst Fe3O4-MNPs@MMT-K10. This catalyst was characterized by energy-dispersive X-ray spectroscopy, vibrating sample magnetometry, X-ray diffraction, scanning electron microscopy, and transmission electron microscopy techniques. Its catalytic behavior was efficiently used for the synthesis of highly substituted pyran/chromene derivatives (4a–m and 6a–m, respectively) containing propargyl unit through a one-pot three-component condensation of propargyl acetoacetate/3-propargyloxyphenol, malononitrile, and arylaldehydes under microwave-assisted solvent-free conditions. Some important features of this catalyst were found, including short reaction times, excellent yields, lower loading of the catalyst, easy work-up, and recyclability. It was showed that the obtained catalyst exhibited the catalytic stability and the reusability for a minimum of six times without any noticeable decrease in its catalytic activity. Also, thirteen novel substituted propargyl 6-amino-4-aryl-5-cyano-2-methyl-4H-pyran-3-carboxylates 4a–m were synthesized by three-component reaction of propargyl acetoacetate with malononitrile and benzaldehydes using this catalyst. Their structure was determined by measuring the spectral properties as well as by single-crystal X-ray crystallography of a representative compound 4i. 1-Alkyne was one of the two substances needed for click chemistry, along with organic azides and propargyl esters as well as ethers were synthesized for this purpose. [ABSTRACT FROM AUTHOR]

A series of substituted 4H-pyrano[2,3-d]pyrimidines were synthesized from corresponding substituted 4H-pyrans by ring-closing reaction with acetic anhydride or acetic acid in the presence of trifluoroacetic acid as catalyst. The successive alkylation reaction of lactam N–H bond on pyrimidine-4-one ring was carried out using propargylic bromide in dry acetonitrile in the presence of anhydrous potassium carbonate. Three procedures applied for this purpose, including MW-assisted heating conditions at power of 100 W, under conventional heating conditions in water bath at 50 °C, and under ultrasound-assisted heating conditions at 50 °C. Dry acetonitrile was used as reaction solvent. Excellent yields of N-propargyl-4H-pyrano[2,3-d]pyrimidine derivatives were obtained. The single-crystal X-ray structure of compound 6a has been recorded, and the study helps to confirm the structure of synthesized N-propargyl derivative of 4H-pyrano[2,3-d]pyrimidines 6a–6p. [ABSTRACT FROM AUTHOR]

Substituted N-propargyl isatins were synthesized by SN2 reaction of corresponding substituted isatins with propargyl bromide in the presence of anhydrous K2CO3 as base. We reported about study on systematically synthesis of these compounds using heating procedures under different reaction conditions, including microwave-assisted heating conditions at power of 100 W (Procedure A), conventional heating conditions in water bath at 50 °C in acetonitrile (Procedure B), and conventional heating conditions in water bath at 50 °C in DMF (procedure C). The best procedure A was deduced based on the investigations on the reaction conditions. Almost all substituted N-propargyl isatins were new, except compounds with R of H, 5-Me, 5-Cl and 5-Br substituents. The structures of the obtained compounds were confirmed by the modern spectroscopic methods. [ABSTRACT FROM AUTHOR]

An efficient method for the synthesis of O -substituted mandelic acids containing alkenyl, alkynyl, methoxycarbonyl, or phenacyl fragments via the Lewis acid-catalyzed reaction of 1,3-dioxolan-4-ones with different C -nucleophiles is proposed. Image 1 [ABSTRACT FROM AUTHOR]

The reactions of 1,3-dioxolan-4-ones, readily available from α -hydroxy acids and aldehydes, with C -nucleophiles are described. Two possible reaction pathways resulting in O -substituted acids and tri-(hetero)arylmethanes are shown. [ABSTRACT FROM AUTHOR]

Abstract: Reactions of (κ 3-polypyrazolylborato)(benzonitrile)rutheniums [RuCl{B(4-Ypz)4}(PhCN)2] {4-Ypz; 4-bromo-1-pyrazolyl (Y = Br) and 1-pyrazolyl (Y = H) groups} with terminal alkynes were studied. For the reactions with arylalkynes HCn the presence of NEt3, (arylmethyl)(carbonyl)rutheniums [Ru{CH2(aryl)}{B(4-Ypz)4}(CO)(PhCN)] were yielded, indicating alkyne Ceavage, whereas in the absence of NEt3, arylalkyne polymerization proceeded instead of the (arylmethyl)ruthenium formation. Reasonably attributed reaction mechanism shows significant role of the vinylidene intermediates “Ruh name="dbnd" />CH(aryl)”. [Copyright &y& Elsevier]

Thiazoles were obtained in high yields by the reaction of 1H-1-(1′-alkynyl)-5-methyl-1,2,3-benziodoxathiole 3,3-dioxides, which were easily prepared from the reaction of 1H-1-hydroxy-5-methyl-1,2,3-benziodoxathiole 3,3-dioxide and 1-alkynes, with thioamides. Here, the co-product, potassium 2-iodo-5-methylbenzenesulfonate, was recovered quantitatively by simple filtration of the reaction mixture, and was regenerated to 1H-1-(1′-alkynyl)-5-methyl-1,2,3-benziodoxathiole 3,3-dioxides to be reused for the same preparation of thiazoles, keeping good yields. [ABSTRACT FROM AUTHOR]