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1.
Superoxo Co(III) complexes derived from Co(Salpr) and [Co(CN)5]3? reacted with 2,6-di--butyl--benzoquinone methides to give 2,6-di--butyl--benzoquinone and 2,6-di--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
2.
-Nitrophenylhydrazones, unsusceptible to autoxidation, are readily oxygenated in the presence of a five-coordinate cobalt(II)-Schiff base complex, Co(II)(MeOSalen) (Py) leading to quantitative formation of novel 1-(-nitrophenylazo)-1-peroxy Co(III) complexes 2, which were isolated as crystals. A plausible mechanism involving hydrogen abstraction by Co(III)(O2?.) from the substrate followed by formation of a substrate anion Co(III) complex intermediate is proposed. 相似文献
3.
The oxygenation of 4-(N-arylmethyleneamino)-2,6-di--butylphenols with Co(Salpr), a five coordinate Co(II0 Schiff base complex, in CH2Cl2 results in the regioselective hydroperoxylation at the imino carbon to give N-(l-aryl-l-hydroperoxymethyl)-3,5-di--butyl--benzoquinone monoimines, which give exclusively the corresponding amides and 2,6-di--butyl--benzoquinone in an aerobic solution of KOH in 90% EtOH. 相似文献
4.
The oxygenation of 4-alkyl-2,6-di--butylphenols () with Co(II)-Schiff's base complexes in aprotic solvents such as CH2Cl2, THF, Py, and DMF leads to highly selective formation of the corresponding peroxy--quinolato Co(III) complexes. The reaction proceeds by mechanism involving a rate determining hydrogen abstraction by superoxo Co(III) species from giving phenoxy radical, rapid step of electron transfer from Co(II) complex to the phenoxy radical, and dioxygen incorporation into phenolato Co(III) complex thus formed. 相似文献
5.
4-Acyl-2,6-di--butylphenols except 3,5-di--butyl-4-hydroxybenzaldehyde were oxygenated in the presence of Co(Salpr) exclusively at the ortho position to give the corresponding 3,5-di--butyl-6-hydroperoxy-2,4-cyclohexadienone derivatives in quantitative yield. 相似文献
6.
Nmr and UV studies show that -dimethylamino--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
7.
Two steroids, 3-oxo-chol-4-ene-24-oic acid () andi ts unsaturated analog have been isolated from the dorid nudibranch , and the acid has been shown to have antifeedant properties. 相似文献
8.
The nitration of -cresol by nitric acid in aqueous sulphuric acid involves ~40% -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
9.
4-(N-Alkylimino)methyl-2,6-di--butylphenols (), Schiff bases of 3,5-di--butyl-4-hydroxybenzaldehyde can be oxygenated in the presence of Co(Salpr), a five coordinate Co(II)-Schiff base complex to give N-alkyl-3--butyl-5-formyl-2-hydroxy-2-pivaloyl-1,2-dihydropyridines ( as the main product together with 3-formyl-2,5-di--butyl-2,4-cyclopentadienone () and 2,6-di--butyl-4-formyl-6-hydroxy-4,5-epoxy-2-cyclohexenone (). These products result from dioxygen incorporation into the ortho position of . 相似文献
10.
The facile decomposition of methyl chlorodifluoroacetate, induced by either lithium chloride/hexamethylphosphoric triamide complex or potassium fluoride/18-Crown-6 complex, has been carried out in the presence of a variety of olefinic substrates to yield the corresponding -difluorocyclopropanes. The ester decomposition has been determined to yield “free” difluorocarbene a three-step process involving an intermediate chlorodifluoromethide ion. 相似文献
11.
The 1H and 13C nmr spectra of , -9-oxobicyclo[3.3.1]nonane-2,4-dicarboxylic acid, 3, in DMSO-d6 or alkaline D2O, clearly show that it exists in a --conformation with carboxyl groups, thus being the first case of - preference of a bicyclo[3.3.1] nonan-9-one due to the presence of ,-2,4- substituents. 相似文献
12.
The amino acid tyrosine has been shown to be the specific precursor of the isonitrile acid produced by (Bon.) Bain. aggr. 相似文献
13.
Palladium catalysed alkoxycarbonylation of heterocyclic halides affords a simple and versatile synthesis of both and heterocyclic esters where a range of catalysts have been studied and a method to employ inexpensive inorganic bases has been found. 相似文献
14.
A simple intra- and inter-molecular potential for water molecules engaged in hydrogen bonding has been used in a one-dimensional approximation for a theoretical interpretation of the experimental correlation OH/OD versus OH in solid hydrates. The variation in the equilibrium OH(D) distance has also been considered. 相似文献
15.
The optically active 1,3,5---triol was synthesized starting from ()-(-)-malic acid with complete stereoselection, based on the stereoselective reduction of cyclic β-keto acetal and successive transthioacetalization. 相似文献
16.
Di--alkylamines can be synthesized efficiently by a three-step process: (1) oxidation of a -alkylamine to a -alkylnitroso compound with peracetic acid in ethyl acetate (2) conversion of the -alkylnitroso compound to a tri--alkylhydroxylamine by successive trapping of two -butyl radicals and (3) sodium naphthalide reduction to the di--alkylamine. 相似文献
17.
Giovanni Fronza Claudio Fuganti Piero Grasselli Giulio Marinoni 《Tetrahedron letters》1979,20(40):3883-3886
The enantiomeric alcohols () and (), obtained from (2,3) tartaric acid and, respectively, -threonine, have been used to construct the C6, enantiomeric deoxy amino sugar derivatives () and () 相似文献
18.
Eiichi Kitazawa Akira Ogiso Shuji Takahashi Masaaki Kurabayashi Harumitsu Kuwano Tadashi Hata Chihiro Tamura 《Tetrahedron letters》1979,20(13):1117-1120
Two new diterpenelactones named plaunol A () and B () exhibiting anti-Shay ulcer activity were isolated from Thai medicinal plant, . Structure of was determined by X-ray analysis of its -bromobenzoate and structure of was deduced from the results of chemical correlation and the spectral data. 相似文献
19.
The transannular cycloaddition between the double bond on the side chain and the -benzoquinone ring in -C8-bridged -benzo-quinones by way of an oxyallyl intermediate is described. 相似文献
20.
The cycloaddition of the dispiro compound, , with a variety of 1,3-butadienes affords diacetates of -C8-bridged hydroquinones, which are led to the corresponding hydroquinones and -benzoquinones. 相似文献