- Route to benzo- and pyrido-fused 1,2,4-triazinyl radicals via N ′-(Het)aryl- N ′-[2-nitro(het)aryl]hydrazides
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A two-step route to 1,3-disubstituted benzo- and pyrido-fused 1,2,4-triazinyl radicals is presented. The route involves the N′-(2-nitroarylation) of easily prepared N′-(het)arylhydrazides via nucleophilic aromatic substitution of 1-halo-2-nitroarenes, which in most cases gives N′-(het)aryl-N′-[2-nitro(het)aryl]hydrazides in good yields. Mild reduction of the nitro group followed by an acid-mediated cyclodehydration gives the fused triazines, which upon alkali treatment afford the desired radicals. Fifteen examples of radicals are presented bearing a range of substituents at N-1, C-3, and C-7, including the pyrid-2-yl and 8-aza analogues. This route to the N′-(het)aryl-N′-[2-nitro(het)aryl]hydrazides, which works well with benzo- and picolinohydrazides, required a modification for aceto- and trifluoroacetohydrazides that involved a multistep synthesis of asymmetrically 1,1-diaryl-substituted hydrazines.
- Berezin, Andrey A.,Zissimou, Georgia,Constantinides, Christos P.,Beldjoudi, Yassine,Rawson, Jeremy M.,Koutentis, Panayiotis A.
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p. 314 - 327
(2014/01/17)
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- A Study of 1,4-Dihydro-1,2,4-benzotriazinyl Radicals
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The thermal cyclization of the azo compounds 2 to yield the 1,4-dihydro-1,2,4-benzotriazines 5 facilitates the synthesis of 1,4-dihydro-1,2,4-benzotriazinyl radicals (4).A series of these radicals were prepared and studied in detail (chemical properties,
- Neugebauer, Franz Alfred,Umminger, Irmgard
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p. 1205 - 1225
(2007/10/02)
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