96129-41-8

Upstream product

• 14508-49-7 2-chloropyrazin 
• 536-74-3 phenylacetylene 
• 56423-63-3 2-bromopyrazine 
• 32111-21-0 2-iodopyrazine 
• 38521-06-1 2(1H)-pyrazinethione 

Downstream Products

• 1221793-93-6 5-methyl-7-(pyrazine-2-carbonyl)-5,6-dihydro-4H-dibenz[de,g]isoquinoline-4,6(5H)-dione 
• 1221793-91-4 7-benzoyl-5-methyl-4H-isoquinolino[5,4-fg]quinoxaline-4,6(5H)-dione 

Relevant academic research and scientific papers

A Waste-Minimized Approach to Cassar-Heck Reaction Based on POLITAG-Pd0 Heterogeneous Catalyst and Recoverable Acetonitrile Azeotrope

Three different Pd0-based heterogeneous catalysts were developed and tested in the Cassar–Heck reaction (i. e., copper-free Sonogashira reaction) aiming at the definition of a waste minimized protocol. The cross-linked polymeric supports used in this investigation were designed to be adequate for different reaction media and were decorated with different pincer-type ionic ligands having the role of stabilizing the formation and dimension of palladium nanoparticles. Among the ionic tags tested, bis-imidazolium showed the best performances in terms of efficiency and durability of the metal catalytic system. Eventually, aqueous acetonitrile azeotrope was selected as the reaction medium as it allowed the best catalytic efficiency combined with easy recovery and reuse. Finally, the synergy between the selected catalyst and reaction medium allowed to obtain highly satisfactory isolated yields of a variety of substrates while using a low amount of metal catalyst. The high performance of the designed POLymeric Ionic TAG (POLITAG)-Pd0, along with its good selectivity achieved in a copper-free process, also led to a simplified purification procedure allowing the minimization of the waste generated as also proven by the very low E-factor values (1.4–5) associated.

Sonogashira-type cross-coupling reactions catalyzed by copper complexes of pincer N-heterocyclic carbenes

Copper complexes of N-heterocyclic carbenes (NHC) have recently received great attention in catalysis, however, the application scope has been limited to neutral complexes bearing monodentate ligands. Herein, we report the synthesis and full characterization of a cationic Cu-pincer bis(NHC) complex with bulky tert-butyl wingtips that serves as catalyst for the coupling of aryl iodides and phenylacetylene, alongside its analogs with small alkyl substituents. Unlike other copper catalysts that require an inert atmosphere to prevent alkyne homocoupling, a competing side reaction to Sonogashira reaction, the Cu-pincer bis(NHC) complexes provide good to excellent cross-coupling yields in air. Interestingly, the reaction under argon affords substantially reduced cross-coupling, indicative of the oxygen involvement and its facilitating effect in the mechanism. In our controlled studies, the air-assisted cross-coupling reaction came to a complete stop when using a radical trap, suggesting the presence of a radical in the mechanism. Examining the reaction of Cu-pincer bis(NHC) complexes with oxygen via UV–vis spectroscopy reveals a dark green chromophore formation at ?40 °C with strong absorbance (ε > 400 M?1cm?1) at 460 nm and 500 nm, likely due to a high-valent copper-oxygen adduct.

Palladium-catalyzed desulfurative Sonogashira cross-coupling reaction of 3-cyano assisted thioamide-type quinolone derivatives with alkynes

A Pd-catalyzed Cu-mediated desulfurative Sonogashira cross-coupling reaction of thioamide-type quinolone derivatives was proposed for the construction of Csp2-Csp bonds. Alkynylated quinoline derivatives can be easily synt

Palladium precatalysts containing meta-terarylphosphine ligands for expedient copper-free Sonogashira cross-coupling reactions

Three novel palladium complexes utilizing different variations of the evolutionary meta-terarylphosphine ligand, CyPhine, were developed. These air- and moisture-stable complexes, PdCl2L2 (L = CyPhine, CyPhine-CF3 and CyPhine-nBu), demonstrated exceptional broad-based performance and operational simplicity in the copper-free Sonogashira cross-coupling of challenging (hetero-)aryl chlorides and terminal alkynes. Modifications to the periphery of the ligand scaffold showed modest improvements in the reaction rate when more electron-donating substituents were incorporated, which hints at potential design upgrades in the future.

Flow-based, cerium oxide enhanced, low-level palladium sonogashira and heck coupling reactions by perovskite catalysts

A flow chemistry procedure for Sonogashira and Heck cross-coupling reactions using a low-level palladium perovskite catalyst (LaFe 0.95Pd0.05O3) deposited on cerium oxide is reported. The catalyst was generated in situ at

A general catalyst for Suzuki-Miyaura and Sonogashira reactions of aryl and heteroaryl chlorides in water

We report the synthesis of 2-(3-sulfonatomesityl)-5-sulfonatoindenyl) dicyclohexylphosphine hydrate sodium salt and its use in palladium-catalyzed Suzuki-Miyaura and Sonogashira coupling reactions in water (and biphasic water-organic solvent mixtures) to prepare a variety of functionalized biaryls and aryl alkynes in excellent yield. This journal is the Partner Organisations 2014.

A straightforward copper-free palladium methodology for the selective alkynylation of a wide variety of S-, O-, and N-based mono- and diheterocyclic bromides and chlorides

High-yield alkynylations are successfully achieved by a simple and widely accessible catalytic system for an unprecedented variety of heterocyclic bromides and chlorides in position -2, -3 or -5: pyridine, quinoline, thiophene, furan, thiazole, benzothiazole, pyrimidine, pyridazine, pyrazine, dioxepin halides are efficiently functionalized in short time reactions. This copper-free methodology employs 1 mol % palladium only, with inexpensive PPh3 and amine base. The ionic liquid solvent allows a straigtforward separation of products and recycling opportunity. Unsuitable substrates and secondary reactions are also reported in order to point out further progress in cross-coupling using ionic liquids.

Reusable Cu2O/PPh3/TBAB system for the cross-couplings of aryl halides and heteroaryl halides with terminal alkynes

(Chemical Equation Presented) An efficient and reusable Cu 2O/PPh3/TBAB (n-Bu4NBr) system for the cross-coupling reactions of aryl and heteroaryl halides with terminal alkynes has been developed. Four types of Cu2O, including bulky Cu 2O, cubic Cu2O nanoparticles, octahedral Cu2O nanoparticles, and spherical Cu2O nanoparticles, were examined, and the octahedral Cu2O nanoparticles were found to be the most effective catalyst for the reaction. In the presence of the octahedral Cu2O nanoparticles, PPh3, and TBAB, a variety of aryl and heteroaryl halides were reacted with alkynes including alkynols smoothly in moderate to good yields. Noteworthy is that the Cu2O/ PPh3/TBAB system can be recovered and reused several times without loss of any activities.

Triplet acetylenes as synthetic equivalents of 1,2-bicarbenes: Phantom n,π* state controls reactivity in triplet photocycloaddition

Diaryl acetylenes, in which one of the aryl groups is either a pyridine or a pyrazine, undergo efficient triplet state photocycloaddition to 1,4-cyclohexadiene with formation of 1,5-diaryl substituted tetracyclo[3.3.0. 02,8.04,6]octa