L-Proline has been successfully anchored on the surface of magnetic nanoparticles and characterized using powder X-ray diffraction, scanning electron microscopy, vibrating sample magnetometry and Fourier transform infrared spectroscopy. These nanoparticles as a chiral catalyst have been employed to promote the direct asymmetric Mannich reaction. The corresponding products are obtained in high yields with high level of diastereoselectivity (up to 99:1 dr) in the presence of Fe 3 O 4 -L-proline. Also this heterogeneous catalyst can be recovered easily and reused many times without significant loss of its catalytic activity.

Magnetically separable Fe3O4 nanoparticles supply environmentally friendly procedure for the synthesis of 14-aryl-14H-dibenzo[a,j]xanthene and 1,8-dioxo-octahydro-xanthene derivatives. These compounds were obtained in high yields and short reaction times by the reaction of dimedone and 2-naphthol with various aromatic aldehydes under solvent-free conditions. The catalyst coluld be easily recovered using an external magnet and reused for six cycles with almost consistent activity

Preparation of chitosan nanoparticles (CS-NPs) was examined from shrimp shells for their catalytic activity. The yield of crude chitosan was 87.8%. The structure of chitosan nanoparticles was determined by FT-IR, SEM and XRD analysis. Then, diastereoselective synthesis of dihydropyrroles was done using chitosan nanoparticles in water under ultrasonic irradiation. This polymeric nanocatalyst could be used instead of the old toxic commercial organic basic catalysts and could be readily isolated from the reaction mixture and recycled several times without significant loss of catalytic activity.

ZnO nanoparticles as a worthwhile and recyclable catalyst have been used for the one-pot synthesis of 1,8-dioxo-decahydroacridines and 1,8-dioxooctahydro-xanthenes via multi-component reactions under solvent-free conditions. The presented method is mild, environmentally friendly, inexpensive and highly effective to give the products in good to excellent yields.

The ultrasound-assisted preparation of 2-(1H-tetrazol-5-yl) acrylonitrile derivatives via a one-pot multi-component method is described successfully using ZrP 2 O 7 nanoparticles as a catalyst. Readily available tetrazoles can be transformed into the corresponding 1,5-and 2,5-disubstituted tetrazoles. 2,4′-Dibromoacetophenone gave the corresponding 2,5-disubstituted derivative as the only isomer. Synthesis of tetrazole derivatives with excellent yields in short times, a wide range of products under ultrasound irradiation, environmental benignity and a simple work-up procedure are some of the important features of this protocol.

AgI Nanoparticles as a Remarkable Catalyst in the Synthesis of (Amidoalkyl)naphthol and Oxazine Derivatives: An Eco-Friendly Approach. -Facile and environmentally friendly routes for the synthesis of amidoalkylnaphthol (VII) and related oxazine derivatives [cf. (IX), (IV)] via AgI-catalyzed multicomponent reactions of -naphthol are developed. -(SAFAEI GHOMI*, J.; ZAHEDI, S.; GHASEMZADEH, M. A.; Monatsh. Chem. 145 (2014) 7, 1191-1199, http://dx.doi.org/10.1007/s00706-014-1184-y ; Dep. Chem., Islamic Azad Univ., Qom, Iran; Eng.) -H. Toeppel 47-193

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