2- Azaspiro deca-6,9-diene-3,8-diones

Andreana and Santra have investigated the influence of the solvent on the generation of molecular diversity arising from a set of MCR substrates under microwave irradiation [36]. They have found that by using water as solvent, both 2,5-DKPs and 2-azaspiro[4.5]deca-6,9-diene-3,8-diones were obtained through aza-Michael reaction and 5-exo Michael cyclization, respectively. Nevertheless,... 

Andreana and co-workers [188] developed a one-pot method for generating molecular diversity via a multicomponent coupling reaction under microwave irradiation. The initially formed Ugi four-component coupling products gave rise to three structurally distinct scaffolds depending on the solvent effects and sterics the 2,5-diketopiperazines 137, the 2-azaspiro[4.5]deca-6,9-diene-3,8-diones 138, and the thiophene-derived Diels-Alder tricyclic lactams 139 (Scheme 107). 

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