Synthesis and Characterization of 2‐(2‐Pyridinyl)pyrazine and 2,2′‐Bipyrazine Derivatives

Abstract

A convenient and high yield preparation of derivatives of 2‐(2‐pyridinyl)pyrazine and derivatives of 2,2′‐bipyrazine compounds from their derivatives of bromopyrazine using Stille coupling is reported. X‐ray structures, elemental analyses, 1H, 13C‐NMR, and mass spectral data of the compounds are given.

Regioselective Syntheses of Imidazo[4,5-b]pyrazin-2-ylidene-Based Chelates and Blue Emissive Iridium(III) Phosphors for Solution-Processed OLEDs

“…35 After then, the cyano group was converted to an amino group using a mixture of sodium hypochlorite and sodium hydroxide solution by way of Hoffman rearrangement. 36 Bromination was next executed using N-bromosuccinimide in giving 3-bromo-5-(t-butyl)pyrazin-2-amine. After then, the formamidine derivatives (1) and (2) were obtained by the treatment of 3-bromo-5-(tbutyl)pyrazin-2-amine with triethyl orthoformate in the presence of catalytic amount of conc.…”

“…All reactions started from commercially available pyrazinecarbonitrile, to which the t -butyl group was introduced utilizing Minisci alkylation, in the presence of both silver triflate and pivalic acid . After then, the cyano group was converted to an amino group using a mixture of sodium hypochlorite and sodium hydroxide solution by way of Hoffman rearrangement . Bromination was next executed using N -bromosuccinimide in giving 3-bromo-5-( t -butyl)­pyrazin-2-amine.…”

Cycloparaphenylene Lemniscates and Trefoils

“…Compound 13 is close to the core of 5CC and 6CC . For the other cores, the nitrogen-substituted fluorenes 14 are commercially available, and the carbenes 15 have been prepared. , For the loops, 2,2′-bipyrazine I has been prepared along with a recent improvement in its synthesis . 2,5′-Bipyrimidine J and 3,3′-bipyridazine K , have also been synthesized.…”

“…38,39 For the loops, 2,2′-bipyrazine I has been prepared 40 along with a recent improvement in its synthesis. 41 2,5′-Bipyrimidine J 42 and 3,3′-bipyridazine K 43,44 have also been synthesized. We hope these computations might inspire the synthesis of additional examples of cycloparaphenylene lemniscates and trefoils.…”

Iodine‐Catalyzed Double [4+2] Oxidative Annulations for the Synthesis of Bipyrazines from Ketones and Diamines by a Domino Strategy

“…[13] However, to the best of our knowledge, no report on double oxidative annulations of ketones and diamines for the construction of dimeric pyrazine skeleton has been shown. The methods for the synthesis of dimeric pyrazines are primarily dependent on transition metal-catalyzed procedures, involving Suzuki, [14] Heck, [15] Stille, [16] Ullmann [17] and Negishi couplings, [18] as well as other coupling methods [19] (Scheme 1c). However, many transition metals are costly and environmentally unfriendly.…”