HighlightsPhenyl-/aminoalkylsilane-grafted silica gels were used as supports for CaLB.Adsorption onto mixed-function-grafted silica supports resulted in active CaLB.CaLB adsorption and glutardialdehyde cross-linking resulted in enhanced durability.The novel CaLB biocatalysts were used in kinetic resolutions of a secondary alcohol and an amine.The novel CaLBs were robust biocatalysts in continuous-flow biotransformations. AbstractAdsorption onto solid supports has proven to be an easy and effective way to improve the mechanical and catalytic properties of lipases. Covalent binding of lipases onto the support surface enhances the active lifetime of the immobilized biocatalysts. Our study indicates that mesoporous silica gels grafted with various functions are ideal supports for both adsorptive and covalent binding for lipase B from Candida antarctica (CaLB). Adsorption of CaLB on phenyl-functionalized silica gels improved in particular its specific activity, whereas adsorption on aminoalkyl-modified silica gels enabling covalent binding with the proper reagents resulted in only moderate specific activity. In addition, adsorption on silica gels modified by mixtures of phenyl-and aminoalkyl silanes significantly increased the productivity of CaLB. Furthermore, CaLB adsorbed onto a phenyl/aminoalkyl-modified surface and then treated with glutardialdehyde (GDA) as cross-linking agent provided a biocatalyst of enhanced durability. Adsorbed and cross-linked CaLB was resistant to detergent washing that would otherwise physically deactivate adsorbed CaLB preparations. The catalytic properties of our best immobilized CaLB variants, including temperaturedependent behavior were compared between 0 and 70 °C with those of two commercial CaLB biocatalysts in the continuous-flow kinetic resolutions of racemic 1-phenylethanol rac-1a and 1-phenylethanamine rac-1b.

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A series of 9-aryl-hexahydroacridine-1,8-diones are synthetized with good to excellent yields (50-99%) via a one-pot fourcomponent reaction of dimedone, aromatic aldehydes and ammonium acetate in the presence of 4 Å molecular sieves modified with iron(III) as an efficient heterogeneous catalyst, in ethanol. The process offers the advantages of high yields, mild reaction conditions and easy work-up procedure. The catalyst can be reused without significant loss of activity.

A series of pentasubstituted 4H-pyrans and tetrahydrobenzo[b]pyrans are synthesized with excellent yields via a one-pot condensation of aromatic aldehydes, malononitrile, and a dicarbonyl compound, ethyl acetoacetate, acetyl-acetone or dimedone, in the presence of 4 Å molecular sieve modified with zinc(II) as heterogeneous catalyst, in ethanol. The process offers numerous advantages, such as better yield, short reaction time, and mild reaction conditions. The catalyst’s preparation is simple and it could be reused while still maintaining its activity.

Copper(II) on 4-Å molecular sieves is an efficient catalyst for the preparation of imines from benzylamines under simple reaction conditions. No oxidative atmosphere or oxidizing agents are required. Preparative experiments showed that no aldehyde intermediate can be detected even under ambient atmospheric conditions. Graphical abstract H 2N-CH(R')-R'' N CH(R')-R'' NH 2 Cu 2+ /4A 120 °C, 14 h neat +