Hozeyfa Sagir

Molecular iodine catalysed domino cyclization in aqueous medium: a simple and efficient synthetic route to 1,4-dihydropyridazines

A facile, efficient and environmentally friendly approach has been developed for the diverse synthesis of 1,4-dihydropyridazines from (E)-2-benzylidene-1-phenylhydrazine and α,β-unsaturated aldehyde under aqueous condition using molecular iodine as a green and recoverable catalyst. This procedure features low cost and easily available starting materials, an inexpensive and recoverable catalyst, short reaction time, reliable scalability, excellent yield and mild reaction conditions, as well as use of aqueous medium. The scope of this method was thoroughly explored under three different reaction conditions resulting in the generation of a library of title compounds. In view of the various advantages of the present investigation, this methodology gives a convenient and straightforward pathway to construct 1,4-dihydropyridazines in an eco-friendly fashion.

S-Nanoparticle/SDS: an efficient and recyclable catalytic system for synthesis of substituted 4H-pyrido[1,2-a]pyrimidines in aqueous admicellar medium

A novel and green methodology has been described for the synthesis of substituted 4H-pyrido[1,2-a]pyrimidines under admicellar catalysis by sulfur nano-particles that can be efficiently recycled up to the fifth run. The greenness of the procedure was well established, as organic solvent was avoided in the reaction media as well as in the preparation of catalyst.

ZnO nanoparticle–β-cyclodextrin: a recyclable heterogeneous catalyst for the synthesis of 3-aryl-4H-benzo[1,4]thiazin-2-amine in water

A combination of ZnO nanoparticles and β-cyclodextrin was used as an efficient and green catalytic system for the synthesis of 3-aryl-4H-benzo[1,4]thiazin-2-amine via a one-pot, three-component reaction of an o-amino thiophenol, aromatic aldehydes and isocyanides in good to excellent yields at 60 °C in water. The nano size of ZnO was confirmed by transmission electron microscopy (TEM), XRD and UV-visible spectral techniques. A high catalytic activity and easy recovery and reuse for several cycles with consistent activity are additional eco-friendly attributes of this catalytic system.

A green route for the synthesis of pyrrolo[2,3-d]pyrimidine derivatives catalyzed by β-cyclodextrin

Herein, we present the synthesis of pyrrolo[2,3-d]pyrimidine derivatives, which are important heterocyclic scaffolds in the field of synthetic and pharmaceutical research, via biomimetic catalysis. This strategy involves the use of β-cyclodextrin as a reusable promoter and water as an eco-friendly reaction medium. The merits of this protocol are high atom economy, mild reaction conditions, good yields of desired products in short reaction times, and reusable reaction medium.

Visible-Light-Mediated Synthesis of 4 H -benzo[1,4]thiazin-2-amines and 3,4-Dihydroquinoxalin-2-amines: An Efficient and Metal Free Route to C–S, C–N Bond Formation

An efficient and practical synthesis of benzothiazine by visible-light-mediated free radical reaction has been developed. This protocol provides a new, facile, eco-friendly strategy to construct benzothiazine and quinoxaline derivatives via formation of C–S and C–N bonds under metal-free condition. This synthesis has been performed under visible light illumination in aqueous ethanol at room temperature using aromatic aldehyde, o-aminothiophenol and isocyanide as reactants.Graphical Abstract