Fused heterocycles sharing at least one heteroatom

The microwave-assisted chemistry of a variety of aromatic heterocycles has been extended to the synthesis of fused molecules which share, at least, one heteroatom. In this area, the synthesis of nitrogen containing compounds has been actively investigated. All the compounds described below have been prepared in an effort to find compounds with interesting biological activity. 

An improved modification of the Ganesan synthesis of Luotonin A has been developed under microwave heating for the synthesis ofvarious annulated [ 1,2-b ] quinazolinones. 

The examples described in this chapter demonstrate that microwave-assisted synthesis can allow easy and rapid access to various aromatic heterocyclic compounds, which may have interesting pharmaceutical potential. These aromatic heterocyclic compounds have 

We have also shown that performing microwave-heated reactions should be considered with special attention. A few of these considerations can be applied generally in conducting microwave-heated reactions and include the following (a) the ratio between the quantity of the material and the support (e.g. graphite) or the solvent is very important (b) for solid starting materials, the use of solid supports can offer operational, economical and environmental benefits over conventional methods. However, association of liquid/solid reactants on solid supports may lead to uncontrolled reactions, which may result in worse results than those obtained by the comparative conventional thermal reactions. In these cases, simple fusion of the products or addition of an appropriate solvent may lead to more convenient mixtures or solutions for microwave-assisted reactions. 

The strategies explored and defined in the various examples presented here open the door to wider application of microwave chemistry in industry. The most important problem for chemists today (in particular, drug discovery chemists) is to scale-up microwave chemistry reactions for a large variety of synthetic reactions with minimal optimisation of the procedures for scale-up. At the moment, there is a growing demand from industry to scale-up microwave-assisted chemical reactions, which is pushing the major suppliers of microwave reactors to develop new systems. In the next few years, these new systems will evolve to enable reproducible and routine kilogram scale microwave-assisted synthesis. 

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