Straightforward Synthesis of 3‐Aminothiophenes Using Activated Amides

Green methodologies for the synthesis of 2-aminothiophene

Pollution and the rising energy demand have prompted the design of new synthetic reactions that meet the principles of green chemistry. In particular, alternative synthesis of 2-aminothiophene have recently focused interest because 2-aminothiophene is a unique 5-membered S-heterocycle and a pharmacophore providing antiprotozoal, antiproliferative, antiviral, antibacterial or antifungal properties. Here, we review new synthetic routes to 2-aminothiophenes, including multicomponent reactions, homogeneously- or heterogeneously-catalyzed reactions, with focus on green pathways.

Recent strategies in the synthesis of thiophene derivatives: highlights from the 2012-2020 literature

Thiophene-based analogs have been fascinated by a growing number of scientists as a potential class of biologically active compounds. Furthermore, they play a vital role for medicinal chemists to improve advanced compounds with a variety of biological effects. The current review envisioned to highlight some recent and particularly remarkable examples of the synthesis of thiophene derivatives by heterocyclization of various substrates from 2012 on.

Keteniminium Salts: Reactivity and Propensity toward Electrocyclization Reactions

A predictive computational study was conducted in order to assess the efficiency of electrocyclization reactions of keteniminium salts, in an effort to form a variety of heterocyclic systems, namely, 3-amino(benzo)thiophenes, 3-amino(benzo)furans, 3-aminopyrroles, as well as 3-aminoindoles. A density functional theory (DFT) approach was utilized and the effect of heteroatoms (NMe, O, S) was thoroughly investigated by means of population analysis, QTAIM, NICS, ACID, and local reactivity descriptors (Parr and Fukui functions). The electrocyclization of enamines leading to 3-aminopyrroles was shown to be both kinetically and thermodynamically most favorable. Moreover, the pericyclic nature of the electrocyclizations was confirmed using FMO, QTAIM, NICS, and ACID methods. Additionally, substituent effects were investigated in order to give further insight on the reactivity of heteroatom containing keteniminium systems toward electrocyclization reactions. Finally, computational predictions were experimentally confirmed for a selection of keteniminium systems.