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1,2:5,6-Di-O-isopropylidene-3-O-[3-(uracil-1-yl)propionoyl]-α-D-glucofuranose and 1,2-mono-O-isopropylidene-6-O-[3-(uracil-1-yl)propionoyl]-α-D-glucofuranose were synthesized.  相似文献   

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A new method for preparing D -glucose polymers is described. Isopropylidene derivatives of D -glucofuranose, particularly the 1,2-mono-O-derivative, are treated with Lewis acids, such as boron trifluoride, to eliminate acetone and produce a highly branched polymer with a molecular weight of 12,700. Approximately one isopropylidene unit remains, possibly on the potential reducing end of the glucan. Up to 95% of the polymer units are D-glucopyranoside units indicating that ring expansion occurs during the condensation.  相似文献   

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鱼腥藻毒素(Anatoxin-a)是自兰藻类水华鱼腥藻(Anabaena flos-aquae)中分离的一种氮杂双环胺类生物碱,其化学结构及绝对构型经X光晶体衍射法测定分析为:(1R,6R)(+)-2-乙酰基-9-氮双环[4.2.1]壬-2-烯,简称为AnTX-a。  相似文献   

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A 3:1 mixture of (+)-(2S, 6S)-trans-α-irone ((+)-1) and (?)-(2S, 6S)-trans-γ-irone (?)-2) has been synthesized with ca. 70% e. e. by the ene reaction of (?)-(S)-3 and but-3-yn-2-one.  相似文献   

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In continuation of our work on penem antibiotics, novel chiral (5R,6S)-2-(1′-aminoalkyl)-6-(hydroxyalkyl)-derivatives 1 have been synthesized by two essentially different strategies. Whereas the starting materials for 1a - f , azetidinones 2 and 5 , were obtained from chiral building blocks (6-aminopenicillanic acid and L-threonine, resp.), the one for 1g , azetidinone 9 , was derived from racemic 4-acetoxyazetidinone and, as chiral auxiliary, (2R)-2-mercaptopropan-1-ol. The 2-aminomethyl derivatives 1a (CGP 30 779) and 1f (CGP 31 608) proved the most potent compounds in the antibacterial tests in vitro and showed a well-balanced spectrum of activity by comparison with that of established β-lactams.  相似文献   

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Conclusions We have synthesized 1,2-O-(1-cyanoethylidene)-3,6,2, 3,4-penta-O-acetyl-6-O-trityl-4-O--D-glucopyranosyl--D-glucopyranose, which is a potential monomer for polycondensation.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2571–2573, November, 1977.  相似文献   

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