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2,6-Dioxatricyclo [3.3.2.03,7]decane, a Novel Isomer of 2,6-Dioxaadamantane Restriction among the great number of possible diheterotricyclodecanes to such with a carbocyclic 8membered ring (cyclooctane) as basic skeleton, which is crosswise bridged by two heteroatoms, and restriction to 5-, 6- and 7membered heterocyclic rings results in the isomeric diheterotricyclodecanes of the following five different structural types: 2,6-diheteroadamantane (a) , 2,7-diheteroisotwistane (b) , 2,7-diheterotwistance (c) , 2,8-diheterohomotwistbrendane (d) , and 2,6-diheterotricyclo [3.3.2.03,7]decane (e ; s. Scheme 1). Starting from a suitably C (5)o(2)-functionalized 2,7-dioxaisotwistane, first representatives with the hitherto unknown skeleton of type e were prepared by molecular rearrangement involving neighboring group participation: 2,6-dioxatricyclo [3.3.2.03,7]decane (41) and the derivatives 34–40 thereof (Scheme 7). 相似文献
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A New Approach to Bicyclo[4.1.0]heptane Derivatives The reaction of the dienone 1 with ethyl α-bromoacetate does not furnish the expected glycidic acid ester 2 but leads to the bicyclo[4.1.0]heptenone derivative 3 . The structure of this new compound has been proved by means of spectroscopic methods (1R, 1H-NMR, 13C-NMR, MS). The elucidation of the configuration at C(7) could be realized by measuring a NOE effect. Other α-alkylated α-bromoacetates react with 1 in the same manner. 相似文献
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Tricyclo[3.3.2.03,7]decane (9-Homo-nor-adamantane). Synthesis and Transformations A synthesis of tricyclo [3.3.2.03,7]decane (=9-homo-nor-adamantane; 1 ), which belongs to the adamantaneland, a family of nineteen isomeric C10H16 hydrocarbons, is described, as well as derivatives thereof. Treatment of protoadamantan-5endo-ol (11) with either thionyl chloride or phosphorus pentachloride yielded under rearrangement the chloride 18 , and solvolysis of the 5endo-chloro-protoadamantane (16) led to the acetate 26, 18 and 26 having both the tricyclo [3.3.2.03,7]decane skeleton. Subsequent transformations gave the title compound 1 as well as the corresponding olefin 8 . 相似文献
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Pierre Martin 《Helvetica chimica acta》1993,76(2):988-992
An Easy Access to PQQ A novel and short synthesis of PQQ , the cofactor of quinoproteins and maybe a vitamine, starting from the known cumarin 6 without any chromatographic purification of the intermediates is described. 相似文献
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Summary A novel synthesis to prepare dibenzo-8-quinolizinones8 is reported using the intramolecular cyclisation of the benzylated Reissert compounds6 for the key step. Methylation of8 by methyllithium gives partial deoxygenated coralynes10 which in turn can be reduced by NaBH4 yielding the 8-methyltetrahydro-protoberberines11. The structures are assigned by NMR-spectroscopy. 相似文献
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A New Synthetic Route to Ubiquinones Ubiquinones 11 have been prepared employing a new strategy: as key step, the Diels-Alder reaction of 1,1,2-trichloroethene 3 with 2,5-bis[(trimethylsilyl)oxy]-3-methylfuran ( 2 ) has been used for the construction of the quinone part. After methanolysis of the [4 + 2] adducts 4a/4b , further reaction with cyclopentadiene and substitution of the Cl-atoms by MeO groups, the intermediate 7 is obtained. Diketone 7 can easily be alkylated with the desired polyprenyl side chain 9 (X = Br) using a strong base to yield, after a retro-Diels-Alder reaction, the corresponding ubiquinones 11 in high yields. 相似文献
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《Journal of organometallic chemistry》1989,361(3):C54-C56
The copyrolysis of tetrahalogenodiborane(4) (B2X4, X = Cl, Br) or the halogenated carbon compounds such as CX4 or C2X4 yields the new carboranes C2B5X7 and C2B7Cl9 in addition to the vinyl compound C2Br3BBr2 as some of the products. 相似文献
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