Easy Protocol for Synthesizing 2-Aminothiophene Derivatives

In general, G-3CR is considered a MCR with low dimensionality, that is, there are not many possible variations 

In addition to varying the substrates, other authors have worked on the conditions in order to extend the scope of the reaction. In particular, MW [127] and ultrasound [128] irradiations have been applied successfully, decreasing considerably the reactions times. On the other hand, different catalysts have been used substituting the classical secondary or tertiary amines [129], for example, L-proline [130], imidazole [131], cesium carbonate (Cs COj) [132], amine-functional polysiloxanes (AFPs) [133], MgAa mixed oxide as a heterogeneous solid base catalyst [134], ZnO (under solvent-free conditions) [135], bovine serum albumin (BSA) [136], and guanidine-based IL [137]. 

The MCR covered herein has found broad applicability in the synthesis of heterocycles containing Gewald moiety (2-amino-thiophene) (Fig. 12.5), with interesting properties [138] and overall antimicrobial activities, such as phthala-zinediones [139], thienopyridines [140], thienothiadiazines 

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