Direct C≡C Triple Bond Formation from the C=C Double Bond and Direct Hydroxylation into the o -Position of a Nitro Group on the Benzene Nucleus with Potassium t -Butoxide in N , N -Dimethylformamide in the Air
1995; Oxford University Press; Volume: 68; Issue: 7 Linguagem: Inglês
10.1246/bcsj.68.2043
ISSN1348-0634
AutoresShuzo Akiyama, Kunihiko Tajima, Shin’ichi Nakatsuji, Kenichiro Nakashima, Kazuko Abiru, Miwa Watanabe,
Tópico(s)Chemical Reactions and Mechanisms
ResumoAbstract A novel and facile method for direct C≡C acetylenic bond formation from the C=C double bond by treatment with potassium t-butoxide (t-BuOK) in N,N-dimethylformamide in the air has been found in a 9,10-bis(4-substituted styryl)anthracene series, in 4-substituted 4′-nitrostilbene series, and in 1-(p-nitrophenyl)-4-(p-substituted phenyl)-1,3-butadiene series; its scope and limitations have been examined. The ESR spectrum of the reaction against 4-diethylamino-4′ -nitrostilbene was measured to identify an anion radical species expected for explanation of the mechanism of the dehydrogenation reaction. Further, cyclic voltammetric measurements of a series of stilbenes and diphenylacetylenes were carried out in connection with the above mechanism. In many cases, interestingly, the use of a large excess of t-BuOK brought about succeeding hydroxylation into the ortho-position of a nitro group on the benzene nucleus. The simple hydroxylation is useful for the synthesis of substituted 5-(arylethynyl)-2-nitrophenols, which are expected to function as non-linear optical materials with the corresponding non-hydroxy compounds. The ultraviolet-visible and fluorescence spectral properties were measured and discussed also with those of the related compounds.
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