A retrievable nanostructure heterogeneous catalyst, based on lipase (lipase from the fungus Aspergillus niger), namely Fe 3 O 4 -bonded lipase (Fe 3 O 4 NPs@ lipase) was prepared in nano size and fully characterized by several techniques such as Fourier transform infrared spectroscopy, X-ray diffraction, Scanning electron microscopy, Transmission electron microscopy and Vibrating sample magnetometer. The retrievable nanostructure catalyst was asserted to be an efficient catalyst in the synthesis of benzothiazepine and spirobenzothiazine chroman derivatives through three-component reaction of coumarine-3-carboxylic acid derivatives, 2-aminothiophenol, and alkyl isocyanides at room temperature under mild conditions. Graphical Abstract

A series of novel 2,5-dioxopyrrolidines were synthesized by the one-pot reaction of coumarin-3-carboxylic acids 1 with thiourea derivatives and alkyl isocyanides in the presence of Fe 3 O 4 NPs @ lipase as heterogeneous reusable nanobiocatalysts with high yields.

The three-component reaction of the zwitterions generated from dialkyl acetylenedicarboxylates (¼ dialkyl but-2-ynedioates and triphenylphosphine (Ph 3 P) with isoindoline-1,3-diimine (¼ 1H-isoindole-1,3(2H)-diimine) is described (Scheme 1). This reaction affords the corresponding special type of substituted dihydropyrimido[2,1-a]isoindole derivatives in good yields without using any catalyst and activation (Table).Introduction. -In recent years, the construction of the hydropyrimidine frameworks has been the subject of numerous investigations [1], since six-membered pyrimidine and fused pyrimidine heterocycles are ubiquitous structural components of several natural products with a wide range of biological activities [2 -5]. Among them, pyrimidoindoles and pyrimidoisoindoles are well known for their potential biological and pharmacological activities, especially antitumor [6], cytotoxic [7], and anti-HIV [8] activities. Due to the biological activity of fused pyrimidines and the little attention paid to the synthesis of pyrimidoisoindole derivatives [9] [10], we wish herein to report, in continuation of our recent investigations [11 -15], a simple and efficient method for the preparation of novel dihydropyrimido[2,1-a]isoindole derivatives.

The reaction of zwitterions generated from diesters (II) and PPh3 with the 1,3‐diimine (I) is investigated.

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