- Nitrocyclohexadienones : a new class of nitrating agents
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Various nitrocyclohexadienones are proposed as new nitrating agents. These compounds are easy to prepare from corresponding phenols, easy to handle and stable. Nitrocyclohexadienones act as nitronium carriers using rearomatization as the driving force and permit nitration of highly activated substrates under mild conditions and with good yields.
- Lemaire, Marc,Guy, Alain,Roussel, Jacques,Guette, Jean-paul
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p. 835 - 844
(2007/10/02)
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- Formation of 4-Nitrocyclohexa-2,5-dienols by Addition of Organolithium Reagents to 4-Alkyl-4-nitrocyclohexa-2,5-dienones
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Addition of methyllithium to 4-alkyl-4-nitrocyclohexa-2,5-dienones 1a-d (alkyl = Me, Et, i-Pr, t-Bu), to 2,6-dichloro- and 2,6-dibromo-4-methyl-4-nitrocyclohexa-2,5-dienone, and to 4a-nitro-2-oxo-2,4a,5,6,7,8-hexahydronaphthalene gives the corresponding dienols 2a-d, 4e and 4f, and 7g, generally as a pair of diastereomers.Addition of methyl lithioacetate to the same substrates gives dienols 8a-d, 5e and 5f, and 7h.Addition of substituted methyllithiums (XCH2Li, X = CN, CONH2, CONMe2, COMe, SMe, SPh, SOMe, SO2Me, SiMe3, PSMePh, PSPh2), 2-lithio-1,3-dithiane, or lithium phenylacetylide to 1a gives the dienols 9i-u.
- Fischer, Alfred,Sankararaman, S.
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p. 4464 - 4468
(2007/10/02)
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- The Nitration of Some Substituted 4-Methylphenols; X-Ray Crystal Structure of (Z)-3-Bromo-5-(bromonitromethylene)furan-2(5H)-one
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The nitrations of 2-substituted 4-methyl-6-nitrophenols (1a), (1b) and (1c) give 6-substituted 3-methyl-2-nitro-1,4-benzoquinones (2a), (2b) and (2c).Similar reaction of 2,3-dibromo-4-methyl-6-nitrophenol (5) gives 2,3-dibromo-5-methyl-6-nitro-1,4-benzoquinone (7) and the 4-nitratocyclohexa-2,5-dienone (12).In contrast, 2,3,6-tribromo- (4a) and 2,6-dibromo- (4b) 4-methylphenols give 1,4-benzoquinones with loss of the methyl group.Lactone (18) was formed in the nitration of the 2,6-dibromophenol (4b) and its structure was determined by single-crystal X-ray analysis.
- Gray, Michael J.,Hartshorn, Michael P.,Penfold, Bruce R.,Vaugnan, John
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