Synthetic study in pyrimidines and related heterocyclics and new synthetic methods

Abstract

The thesis entitled ?Synthetic study in pyrimidines and related heterocyclics and new synthetic methods?, is structured like this, as the title indicates it is in two parts, part-I deals with multicomponent reaction (MCR) mainly three component like Strecker, Hantzsch and Biginelli reaction and is divided into two chapters which in turn are divided into subsections and each section carries relevant introduction, present state of art in that particular section, results and discussion (author?s work), experimental work and then references relevant to that section. Section 1 of chapter-I describes the present state of the art of MCR, mainly recent developments under solvent and solvent less reaction condition using green and efficient techniques like microwave, ultrasonication, high speed ball milling and grinding (Fig. 1). Figure 1. Section 2 of chapter 1 deals with LiBr catalyzed synthesis of and#945;-amino nitriles. A variety of aromatic, conjugated and heterocyclic aldehydes have been reacted with amines and TMSCN at room temperature to obtain and#945;-amino nitriles. The reaction completes within 50-85 minutes and 10 mol % of catalyst is enough to facilitate the reaction to completion. Further utility and superiority of author?s protocol is demonstrated using conjugated aldehydes, where no double bond migration is observed rather normal nitriles are obtained (Scheme 1). Scheme 1. Suresh, A. Saini and J. S. Sandhu, Synthetic Communications 2008, 38, 3655. Section 3 of chapter-I, presents the brief account on Hantzsch reaction and deals with the synthesis of 1,4-dihydropyridines via condensation of ethyl acetoacetate, aldehydes and ammonium acetate (Scheme 2). The reaction is catalyzed by BiCl3 and RuCl3 in solvent free condition under thermal heating. Scheme 2. Suresh, D. Kumar and J. S. Sandhu, Synthetic Communications, 2009, 39, 1957. Suresh, R. S. Bhatti, P. Krishan and J. S. Sandhu, Indian J. Chem. Soc., 2010, 87, 707. Chapter 2 deals with the Biginelli reaction.