首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 0 毫秒
1.
The transannular cycloaddition between the double bond on the side chain and the p-benzoquinone ring in p-C8-bridged p-benzo-quinones by way of an oxyallyl intermediate is described.  相似文献   

2.
The nitration of p-cresol by nitric acid in aqueous sulphuric acid involves ~40% ipso-substitution at CMe. The 4-methyl-4-nitrocyclohexa-2,5-dien-1-one (I) formed undergoes an acid-catalysed rearrangement to 4-methyl-2-nitrophenol.  相似文献   

3.
The cycloaddition of the dispiro compound, 2, with a variety of 1,3-butadienes affords diacetates of p-C8-bridged hydroquinones, which are led to the corresponding hydroquinones and p-benzoquinones.  相似文献   

4.
Diastereoisomers of 1,4-dimethyl-4-nitro-2,5-cyclohexadienyl acetate exchanged acetoxyls for alkoxyls on irradiation in alcohols to give the diastereoisomers of alkyl, 1,4-dimethyl-4-nitro-2,5-cyclohexadienyl ethers in isomer ratios of 70:30, whereas the irradiation in pentane yielded p-xylene.  相似文献   

5.
Nmr and UV studies show that p-dimethylamino-α-bromostyrene, I, undergoes SNl reaction in H2O and HClO4 (kSNl = 6 × 10?1sec.?1 at 25°). The vinyl cation has an extraordinary selectivity for capture by aromatic amines relative to H2O, including I itself to give the dimer II.  相似文献   

6.
7.
The Diels-Alder reaction of p-benzoquinone with substituted dienoic esters affords good yields of 4a,5,8,a-tetrahydro-1,4-naphthalenediones, free from the isomeric hydroquinone. The reactions were conducted at room temperature under 15 kbar (1.5 GPa) pressure in dichloromethane solutions.  相似文献   

8.
Monomeric p-dimethylamino-α-bromostyrene undergoes SNl increasingly slowly in 60 to 91% dioxane. Reaction is catalyzed by HClO4, NaOH and NaClO4. Dimer 11 reverts to monomer I in 91% dioxane. There is only a small solvent effect on the solvolysis rate of II.  相似文献   

9.
10.
11.
12.
Superoxo Co(III) complexes derived from Co(Salpr) and [Co(CN)5]3? reacted with 2,6-di-t-butyl-p-benzoquinone methides to give 2,6-di-t-butyl-p-benzoquinone and 2,6-di-t-butyl-2,5-cyclohexadienonespirooxiranes as the main products, which are considered to result from nucleophilic attack by the superoxo species on the exo double bond of the quinone methides.  相似文献   

13.
Pyridinium p-toluenesulfonylmethylide serves as a formyl anion equivalent and, in the presence of an alcohol, undergoes 1,4-addition to N-substituted maleimides to give alkoxy- (or aryloxy)-methylene-succinimides. The protected aldehyde group can be liberated readily.  相似文献   

14.
15.
J Leitich 《Tetrahedron letters》1980,21(32):3025-3028
The relative rates of formation of cis and trans [2+2]cycloadducts of benzyne to cis, trans- and cis, cis-1,5-cyclooctadiene, trans- and cis-cyclooctene are discussed and properties of the adducts (e.g., their unusual hydrogenation) are described.  相似文献   

16.
17.
18.
All four isomers of substituted 3-alkylthio-4-hydroxybutenes have been synthesised: both the geometry of the double bond and the relative stereochemistry of the two chiral centres are controlled.  相似文献   

19.
Photolysis of t-butyl azide in N2 matrices at 12 K gives the imine 3a; matrix IR spectra for imines 4a and 5a are also reported.  相似文献   

20.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号