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A novel heterogeneous catalytic method was developed for the synthesis of coumarin and its derivatives using the Ti(IV)-doped ZnO matrix forming catalyst Zn 0.925 Ti 0.075 O having a high surface area and good Lewis acidity. The catalyst shows high activity toward a broad spectrum of the substituted phenols with β-ketoesters such as ethyl acetoacetate, ethyl butyryl acetate, ethyl benzoyl acetate, and so forth in good yields over short reaction times during the synthesis of coumarins. The methodology was further extended for the synthesis of ayapin molecules. The catalyst also shows recycle activity up to seven cycles with very good stability.

One pot catalytic transfer hydrogenation (CTH) of furfural to furfuryl alcohol (FAL) by using hydrogen producing alcohols and simultaneous aldolization of carbonyl compounds produced during CTH, with furfural was achieved over non-noble metal oxides with bifunctional sites. Basic sites of MgO responsible for abstraction of proton showed complete conversion of furfural to give FAL and C8 monomer in a ratio of 3:1, respectively, the later altered to 1:1 by incorporating Al into MgO. Catalyst stability was established by its four cycles study. GraphicalAbstract Keywords Furfural Á Furfuryl alcohol Á Transfer hydrogenation Á Aldol Á Metal oxides Abbreviations Al 2 O 3 Aluminum nitrate B Boron CT Conversion versus time CTH Catalytic transfer hydrogenation FA Furfural-acetone adduct F2A Furfural-acetone-furfural adduct FFR Furfural FAL Furfuryl alcohol 5-HMF 5-hydroxymethyl furfural 5-MF 5-methyl furfural IPA Iso-propyl alcohol MgO Magnesium oxide K Potassium K 2 CO 3 Potassium carbonate Electronic supplementary material The online version of this article (

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A novel, nonleachable hybrid of heteropoly acid and polyvinylpyrrolidone (or povidone) catalyzes the acetalization of aldehydes in methanol at room temperature followed by reaction with indole to give bis(indolyl)methanes (BIMs) and tris(indolyl)methanes (TIMs) in quantitative yields (90–97 %). The catalyst was shown by pyridine FTIR spectroscopy to possess Brønsted acidity, and the hybrid formation was confirmed by XRD and 31P NMR studies. Friedel–Crafts alkylation of indole as well as the tandem synthesis of BIMs and TIMs were established with several types of carbonyl and indole substrates to give the corresponding products quantitatively. The catalyst was recycled efficiently for three successive runs without losing its original activity.

A solid acid (PWA/MCM-41) efficiently catalyzed the deprotection of allyl group from the allyl aryl ethers of various types of substrates, in the presence of other oxygen protecting groups.

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