Quinoxalines. Part 13: Synthesis and mass spectrometric study of aryloxymethylquinoxalines and benzo[b]furylquinoxalines

Evidence for an aryl migration during the electron impact induced fragmentation of substituted aryloxymethylquinoxalines

“…As the most characteristic topic of these studies, the loss of HCN and RCN, respectively, from the studied 2‐alkyl‐ and 2‐arylquinoxalines was reported. We also observed this typical loss of stable neutrals resulting in the [M − HCN] + and [M‐RCN] + ions, during the structural elucidation procedure of the benzfurylquinoxalines studied previously 11. Surprisingly, the corresponding ether derivatives of the quinoxalines, studied in this paper, did not show the typical [M − RCN] + peaks; in contrast, [M − OH] + and/or [M − CHO] + species, dependent on the substitution pattern of the aryl moiety, were observed as the most characteristic fragment ions of the title compounds originating from the molecular ion.…”

“…The 13 C NMR spectra of the quinoxalines studied were examined with respect to the number of carbon atoms and number of protons attached to the latter; finally, both 1 H and 13 C NMR spectra were unequivocally assigned via the 2D NMR experiments H,H‐COSY, HMQC and HMBC, respectively 11…”

A facile synthesis of phenazine and quinoxaline (new 1,4-benzo diazine) derivatives using magnesium sulfate heptahydrate as a catalyst

“…In other variations, with the aim of synthesizing products which have not hitherto been reported, it was found that 1,2-pyridinediamine underwent condensation with compound 2 to produce dibenzo[f,h]pyrido[2,3-b]quinoxaline (8) in 77 % yield (Scheme 2); in a similar way, condensation of 3,4-benzophenonediamine with compound 2 produced dibenzo[a,c]phenazine-11-ylphenylmethanone (9) (Scheme 2). Scheme 2.…”

“…and Pantoea agglomerans, are found in nature These natural phenazine products have been implicated in the virulence and competitive fitness of the producing organisms. 3,4 Quinoxaline and phenazine derivatives constitute the basis of some antitumor agents, 5 bactericides, 6 fungicides, 7 herbicides, 8 and insecticides (e.g., quinalphos). 9 In addition, they are used in dyes, 10 building blocks for the synthesis of organic semiconductors, 11 chemically controllable switches, 12 cavitands, 13 DNA cleaving agents, 14 dehydroannulenes, 15 and electrical-photochemical materials.…”

Are Molecular 5,8‐π‐Extended Quinoxaline Derivatives Good Chromophores for Photoluminescence Applications?

“…These derivatives have been successfully incorporated into polymers for use as electron‐transport materials in multilayer OLEDs 12,13. Several different protocols are available for the synthesis of quinoxalines,14–17 especially when the extension of the π‐conjugation is at the 2‐ and 3‐positions of the quinoxaline unit 18. Simple π‐extension at the 5‐ and8‐positions of the quinoxaline base is difficult to achieve by classical Suzuki and Sonogashira cross‐coupling protocols and only one example of a alkynylation reaction between trimethylsilylacetylene and 5,8‐diiodoquinoxaline, which proceeded in moderate yield, has been reported so far 19.…”