- Preparation of and addition of carbanions to 6-methyl-6-nitrocyclohexa-2,4-dienones
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Nitration of 2-methylphenols with nitric acid and trifluoroacetic anhydride in ether at -78 deg C gives 6-methyl-6-nitrocyclohexa-2,4-dienones that can be isolated.Carbanions add to 5,6-dimethyl-6-nitrocyclohexa-2,4-dienone to give the 5-substituted 2,3-dimethyl-2-nitrocyclohex-3-enone anion, which, with additional carbanion, gives the 5-substituted 2,3-dimethylphenoxide anion by elimination of nitrous acid.Key words: nitration, dienone, addition, carbanion, nucleophilic.
- Fischer, Alfred,Henderson, George N.,Sankararaman, S.
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p. 1244 - 1246
(2007/10/02)
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- FORMATION OF DIENONES ON THE REACTION OF CRESOLS, XYLENOLS, AND 2-NAPHTHOL WITH NITROGEN DIOXIDE: OBSERVATION OF KETO TAUTOMERS OF NITROPHENOLS
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Reaction of o- and p-cresol, the xylenols, and 2-naphthol with nitrogen dioxide gives nitrocyclohexadienones and nitrophenols.Secondary nitrodienones, the keto tautomers of the nitrophenols, have been observed in several cases and are intermediates in the formation of the nitrophenols.
- Fischer, Alfred,Mathivanan, N.
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p. 1869 - 1872
(2007/10/02)
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- ipso Nitration. XXIV. Nitration of 2-methylphenols. Formation and rearrangement of 6-methyl-6-nitrocyclohexa-2,4-dienones
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Nitration of o-cresol and some mono-, di-, and trimethyl derivatives in acetic anhydride at -60 deg C gives 6-methyl-6-nitrocyclohexa-2,4-dienones.The dienones are more labile than the isomeric 4-methyl-4-nitrocyclohexa-2,5-dienones and, if the 2-position of the dienone is not blocked, undergo regiospecific rearrangement to 6-nitro-o-cresols. 2,3,6-Trimethyl- and 2,3,5,6-tetramethylphenol also give a 2,5-dienone with nitro attached to a secondary carbon.
- Cross, Gordon G.,Fischer, Alfred,Henderson, George N.,Smyth, Trevor A.
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p. 1446 - 1451
(2007/10/02)
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