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1.
Gábor Blaskó Natesan Murugesan Alan J. Freyer Daniella J. Gula Bilge Şener Maurice Shamma 《Tetrahedron letters》1981,22(33):3139-3142
Stereoselective rearrangement of indenobenzazepine cis ketols and with TPAA in pyridine produces spirobenzylisoquinolines and , respectively. The latter product is also obtained by rearrangement of trans ketol . The transformation of ketols and must, therefore, proceed through the intermediacy of aziridinium cation . A similar process obtains in the transformation of to . NaBH4 reduction of gives (±)-raddeanine (). Rearrangement of diol supplies directly. (±)-Yenhusomine () is obtained from the reamangement of either diol, or . In like fashion, diols and supply spirobenzylisoquinoline . 相似文献
2.
The ketol and its acetate when refluxed in methanolic potassium hydroxide (5%) were found to rearrange to 4-methyl-8-acetyl-5,6,7,8-tetrahydro-1-naphthol . The epimeric acetate also behaved likewise. A mechanism is suggested for the rearrangement. 相似文献
3.
Elena Tsankova 《Tetrahedron letters》1982,23(7):771-774
The lactone was found to be a co-product of the BF3 etherate induced cyclization of epoxyisogermacrone . The keton when treated with 100% HCOOH afforded the lactone while under the same conditions the ketol gave the corresponding ester . A mechanism is suggested for the rearrangements. 相似文献
4.
The acid catalysed rearrangement of 8-methyl-pentacyclo(5.4.0.02,6.03,10.05,9)undecan-8-endo-o1 () to 3-methyl-(D3)-trishomocuban-4-o1 () provided the key step to the synthesis of the title compound (). 相似文献
5.
David J. Herbert John R. Scheffer Anthony S. Secco James Trotter 《Tetrahedron letters》1981,22(31):2941-2944
Attempted intramolecular pinacolization of cage diketone unexpectedly gave ketol instead. Compound was shown to possess the rare tetracyclo[4.2.1.1.2,503,7]decane ring system by means of an X-ray crystal structure of hydroxy-mesylate derived from by sodium borohydride reduction followed by mesylation. A possible mechanism for the transformation of into is presented, and certain noteworthy features of the crystal structure of are discussed. The base-catalysed fragmentation of to give enone is also described. 相似文献
6.
3-Methylisoxazolo[4,5-c]pyridine on reduction with BH3:THF gave, via the isolable complex , the tetrahydroisoxazolopyridine . The presence of two chlorine atoms at the 4 and 6 positions directed borane attact to the isoxazole ring, yielding the aminoethylpyridine . Both types of reduction were obtained with 6-chloroisoxazolo[4,5-c]pyridine . 相似文献
7.
Previous results from our laboratory plus a simple conformational analysis argument lead to the prediction that irradiation of cyclohexenone in the solid state will give ketol . An independent synthesis of plus a determination of the solid state conformation of by X-ray crystallography show this prediction to be correct. 相似文献
8.
Radicals derived from thiohydroxamic esters readily add to nitroolefins (Z = NO2) to give good yields of α-nitrosulphides. These adducts, where the structure permits, are easily oxidised to carboxylic acids by treatment with alkaline hydrogen peroxide. Reductive cleavage to the corresponding aldehydes or ketones is efficiently carried out by the action of TiCl3. Addition of methyl magnesium iodide to the methyl ketone derived from 3α-acetoxy 11-oxo cholanic acid gives steroid possessing the 25-hydroxycholesterol side chain of the vitamin D3 metabotites. Radical additions to 1-phenylthio-2-nitropropene have been briefly studied. 相似文献
9.
Dimethylphosphite, (CH3O)2P(O)H, adds oxidatively to iridium(I) and rhodium(I) complexes to give hydrido-iridium(III) or -rhodium(III) dimethylphosphonate complexes. A complex Ir(H)Cl[P(O)(OCH3)2][P(OH)(OCH3)2]3 obtained from [IrCl(C8H14)2]2 and dimethylphosphite catalyses the stereo-selective reduction of 4-t-butylcyclohexanone to cis/trans-4-t-butylcyclohexanol, the ratio being identical with that obtained using the Henbest catalyst iridium(IV) chloride, phosphorous acid or one of its esters, and aqueous isopropanol. 相似文献
10.
Gábor Blaskó Natesan Murugesan S.Fazal Hussain Robert D. Minard Maurice Shamma Bilge Şener Mekin Tanker 《Tetrahedron letters》1981,22(33):3135-3138
Fumarofine is not a spirobenzylisoquinoline. Rather, it is the first know reduced indenobensazepine alkaloid, and possesses the cis B/C fused structure . Rearrangement of synthetic spirobensylisoquinoline using methanesulfonyl chloride furnished indenobensazepine . Osmium tetroxide oxidation of gave cis-glysol . O-Methylfumarofine () was then obtained through pyridinium chlorochromate oxidation of . 相似文献
11.
Phosphorus pentafluoride was reported long ago to give adducts 2 PF5 ·5 NH3 (1) and nNH3·PF5 (n= 1 ? 4) (2). None of the compounds was characterised in detail. Repeating the reaction of PF5 and NH3 we found the adduct H3N·PF5, , in 8% yield besides (H2N) 2PF3 (3) and NH4PF6. However, HF and (F2P=N)3 gave in 41% yield. The 1H, 19F, and 31P n.m.r. spectra of exhibit 14NH, 14NPF(cis), and 14NP coupling. The x-ray structure determination shows almost perfect octahedral geometry at phosphorus with a PN bond length of 1.842 ā. Compound is soluble in water without decomposition. Treatment with NH3 leads to the anion H2NPF5?. Upon heating forms in good yield H2NPF4 and NH4PF6. Without a solvent and NH3 react to give (H2N) 2PF3. A mechanism for the ammonolysis of PF5 is proposed. 相似文献
12.
Boźenna Golankiewicz Piotr Januszczyk Maria Gdaniec Zofia Kosturkiewicz 《Tetrahedron》1985,41(24):5989-5994
2-Acylamino-2-cyanoacetic acid ethyl esters react with 2,4-bis (4-methoxyphenyl)-1, 3, 2, 4-dithiadiphosphetane 2,4-disulfide in refluxing benzene with formation of 2-alkyl(aryl)-5-aminothiazole-4-carboxylic acid ethyl esters . Structure was established by spectroscopic means and an X ray crystallographic investigation of . X-Ray analysis revealed that the thiazole ring, exocyclic nitrogen and carbonyl group forming a hydrogen-bonded cycle are nearly coplanar. A resonance interaction is manifested by distinctly shortened /1.447 (3)/ C(carbonyl)-C(thiazole) distance. 相似文献
13.
The acid catalysed reaction of 4-oxa-homoadamantan-5-one () with benzene yielded a mixture of 4a-phenyladamantan-2-one (), the equatorial isomer' () and 2-phenyl-2,4-o- benzenoadamantane () A plausible reaction pathway for the occurrence of . is put forward. The structure of , was deduced from spectroscopic data and reaction of the proposed intermediate 2,4a-diphenyladamantan-2-ol () with acid. 2,4-o-Ben-zenoadamantane () is prepared likewise. 相似文献
14.
Treatment of ortho-palladated complex with styrene in benzene - acetic acid mixture gives complex . The reaction is strongly accelerated in the presence of NaClO4 or LiClO4. 相似文献
15.
The preparation of phosphatidyl-β-glucosyl diglyceride is described. The synthesis of glycophospholipid was accomplished by using: (a) the levulinoyl group for the temporary protection of the glucose hydroxyl functions of , which could then be converted into the dioleoyl substituted derivative ; (b) the tetraisopropyldisiloxane-1,3-diyl (TIPS) group to protect the 3'- and 4'-hydroxyl groups of , in a two step procedure, to afford compound ; (c) a 2,4-dichlorophenyl protected phosphatidic acid derivative . Compound could be selectively coupled to the primary hydroxyl function of to afford the fully protected glycophospholipid . Finally, removal of the 2,4-dichlorophenyl and TIPS protecting groups from was performed with syn-4-nitrobenzaldoximate and fluoride ions, respectively, to afford glycophospholipid . 相似文献
16.
The condensation of p-diazooxide with dimethyl acetylenedicarboxylate at 90°–100°C yields two C26H32O9 products, corresponding to addition of two molecules of ester to one of the carbene . The major product is the novel spirodecatetraenone , and the minor product is the remarkable, nonenolizable naphthalenone . Spirodecatetraenone is not a precursor of , since the former is stable to acids and rearranges only above 200° to give the blocked azulenone . A mechanism for the concomitant formation of product and is proposed. 相似文献
17.
The diene was efficiently transformed into the ketol by a three-step process which includes a novel oxygenation by a chlorochromate reagent. 相似文献
18.
Marek Chmielewski Piotr Guzik Bogumiła Hinjtze Włodzimierz M. Daniewski 《Tetrahedron》1985,41(24):5929-5932
Butyl 2-0-acetyl-4,5-anhydro-3,6-dideoxy-DL-xylo-hexaldonate () in the presence of SnCl4 underwent an intramolecular rearrangement to give 2,5-anhydro ester . On the other hand the lyxo epimeric epoxide under the same conditions afforded esters and . Ester was transformed into racemic epiallomuscarine (), whereas the isomer into racemic epimuscarine (). 相似文献
19.
Alkylation of the distal double bond of pseudoionone has been carried out with isoprene epoxide (ZnCl2 /MeNO2 ) leading directly to α-, α- and γ hydroxyprenylionones. The α- and γ-isomers have been converted in few steps into the C50 carotenoids decaprenoxanthin and C.p. 450 respectively. 相似文献
20.
《Tetrahedron》1987,43(13):3021-3030
A new synthesis of 9,10-dimethoxy-1,3,4,6,7,11b-hexahydro-2H-benzo aquinolizin-2-one ( and its 3-ethyl derivative via the corresponding 2-(3,4-dimethoxyphenyl)-4-piperidone ethylene acetals is reported. Alkylation of 2-arylpipendires with 2-bromoethanol followed by oxidation of the resulting amino alcohols with oxalyl chloride and dimethyl sulfoxide afforded the aldehydes , which were cyclized with hydrochloric acid to give 7-hydroxybenzo[α]quinolizidines . The reduction of with trinethylsilane and subsequent acid hydrolysis led to benzo aquinolizidin-2-ones . 相似文献