Pradip K. Maji

RECENT DEVELOPMENT IN PALLADIUM-MEDIATED SYNTHESIS OF OXYGEN HETEROCYCLES

This review describes the synthesis of nitrogen heterocycles by palladium-mediated cyclization. This report covers literature published during 2003 to 2007.

Efficient One Pot Synthesis of Chromenonaphthyridine Derivatives by CuI/InCl3 Catalyzed Aza Diels-Alder Reaction

A mild and efficient method for the synthesis of chromenonaphthyridine derivatives via domino reaction of aminopyridine and different O-propargylated salicylaldehydes using CuI/InCl3 as an efficient catalyst, refluxed in acetonitrile is reported. Mild reaction condition, operational simplicity, good to excellent yield and easy isolation of product is the silent feature of this reaction. INTRODUCTION Heterocycles are omnipresent in nature and possess important biological and pharmacological activities. They represent many core structures of pharmaceutically important molecules. Naphthyridine derivatives are one of the most important classes of such compounds. Recently synthesis of different heterocyclic compounds including naphthyridine moiety has been reported, as they have potent pharmaceutical as well as excellent biological activity.1 Several naphthyridines derivatives display antibacterial activity,2 medicinal use in cardiac insufficiencies and infarction,3 anticonvulsant activity,4 anti-human cytomegalovirus (HCMV) inhibitors,5 and anticancer activity.6 The development of eco-friendly process in terms of sustainable chemistry has become a focal point in chemical research in recent years. The hetero Diels-Alder reaction is one of the most efficient and powerful synthetic tool for the synthesis of heterocycles.7 Recently various transition metal salts8 is used as catalyst in hetero Diels-Alder reaction among which copper and indium trichloride have been extensively used in organic synthesis. Both copper and indium chloride have gained a considerable attention in organic synthesis due to their commercial availability, stable in air, inexpensive and non-toxic nature. Moreover copper can easily activate the terminal alkyne9 bond and indium trichloride coordinate with imine double bond and facilitate in cyclization through hetero Diels-Alder reaction. So many reports are available in the literature of indium trichloride as a green and potentially Lewis acid catalyst to HETEROCYCLES, Vol. 96, No. 1, 2018 43