An efficient one-pot synthesis of 2-bromo-6-aryl[5H]pyrrolo[2,3-b]pyrazines

Four- and Five-Component Syntheses and Photophysical Properties of Emission Solvatochromic 3-Aminovinylquinoxalines

“…Ethynylquinoxalines should be susceptible to nitrogen nucleophiles, in analogy to alkynones or classical Michael systems (Scheme ), caused by the electron-withdrawing character of the quinoxaline core, furnishing enamine-type structures . Similar strategies were also employed in the synthesis of various heterocyclic scaffolds through an intramolecular ring closure. , …”

Modular synthetic strategies for dipyrrolopyrazines

“…Addition of bases such as Cs 2 CO 3 and KO t Bu failed to convert the starting material. 36 Further attempts to utilise Pd( ii ) and Pd(0) catalysts in various solvents did not yield any detectable product (Table 2, entries 5 & 6). Given the lack of cyclisation observed with the addition of Pd-catalysts, we discarded the Pd and increased the CuI loading to 20% while using Et 3 N as a base, resulting in full conversion of BA2 and a quantitative yield of DPPB2 (Table 2, entry 7).…”

Regioselective synthesis of dipyrrolopyrazine (DPP) derivatives via metal free and metal catalyzed amination and investigation of their optical and thermal properties

“…8,9 Interestingly, Simpson et al described a one-pot protocol for the preparation of pyrrolo [2,3-b]pyrazine starting with a halo-pyrazine derivative. 10,11 More recently, a strategy relying on a crucial C-N nucleophilic aromatic substitution reaction under microwave (MW) irradiation conditions was developed to prepare this substance. [12][13][14][15] It is well known that (metal catalysed) reactions, like the one employed in this sequence, carried out under MW conditions proceed with enhanced regio-and stereoselectivities.…”