In the present work, our objective is to take advantage of the property presented by Ionic Liquids (ILs) based on 1-alkyl-3-methylimidazolium cations by having amphiphilic character when the alkyl group is a long hydrocarbon chain. These ILs can act as surfactants forming micelles in aqueous solution. In this sense, the micellar effect on a Diels-Alder reaction (DA) was analyzed taken as a reference. The reactive system studied consists of maleic anhydride and isoprene, variables such as diene:dienophile ratio and reaction temperatura among the most important were optimized. N,N-dodecylmethylimidazolium bromide was used at the critical micellar concentration (CMC) of 1 × 10⁻² M. These “new systems” microheterogeneous would allow, in addition to better solubilization of non-polar substrates, to adopt milder reaction conditions.

In this work the polar Diels-Alder reactions between 2- and 3-nitrobenzothiophenes derivatives and different dienes, such as 2-methyl-1,3-butadiene and 1-trimethylsilyloxy-1,3-butadiene are studied. Molecular solvent and protic ionic liquids are employed as reaction media. A very strong electron-acceptor group such as nitro group, push the electrophilic character of these heterocyclic compounds. Moreover, this substituent is easily extruded under thermal conditions make this reaction sequence a simple method of organic compound´s families with heteroatom rings preparation.

For polar Diels–Alder (DA) reactions, one of the most relevant aspects is its dependence on the reaction media; thus, in this work, the objective is to analyze the effect of aqueous micellar systems on the synthesis of compounds of biological interest. Based on the system formed by isoprene and 2-nitrofuran, the experiments were carried out in micellar media formed by amphiphilic ionic liquid (N,N-dodecylmethylimidazolium bromide) and by conventional surfactants (SDS and CTAB). In this sense, there are few studies that involve DA reactions in micro-heterogeneous systems. The challenge is to have the knowledge about the behavior of ILs in order to take advantage of all their potentialities in order to replace a toxic molecular solvent with ILs, which allows the development of a methodology framed within the concepts of Green Chemistry.

Herein we report a simple, economical and efficient one-step procedure to synthesize the naphtho[2,1-b]thiophene ring system in good to excellent yield through the polar Diels-Alder reactions of 5-nitro-3-acetylbenzothiophene and dienes of different nucleophilicity. In thermal conditions the reactions were developed in molecular solvents; moreover the reaction system was exposed to microwave irradiation as a complement of reaction conditions.