Nucleosides. 124. 3-Amino-3-deoxyhexopyranosyl Nucleosides. 7. 1-(3-Deoxy-3-Nitro-β-D-glucopyranosyl) Uracil and Its Galactopyranosyl Isomer1

Abstract

Crystalline 1-(3-deoxy-3-nitro-β-D-glucopyranosyl) uracil (3), originally prepared by nitromethane condensation of “uridine dialdehyde,” was found to contain the galactosyl isomer (4). Each isomer was obtained in pure form by 4′,6′-O-benzylidenation of the mixture of 3 and 4, followed by chromatographic separation and subsequent O-debenzylidenation. The structure of each isomer was established by chemical conversion of the isomer into the corresponding known 3′-acetamido-2′,4′,6′-tri-O-acetyl derivative.     

中国蚋科新纪录,3.

作者在整理采自内蒙古自治区的蚋科标本中,发现蚋属3个种系国内新纪录: 1.长须蚋Simulium longipalpe Beltjukava, 1955 模式产地苏联沿乌拉尔山(卡马河)。国內标本采自内蒙古呼伦贝尔盟的喜桂图旗(免渡河,1982Ⅵ.27),1♀,1头蛹。蛹生活于小溪流中石块与草茎上,水温10℃,河宽0.5米,水深6厘米。     

Studien über dieJungermannioideae (Hepaticae) 3.Jungermannia Subg.Liochlaena

Die dritte Studie aus der Serie der vorbereiteten Studien über die SubfamilieJungermannioideae (Jungermanniaceae, Hepaticae) enthält die taxonomische Bearbeitung des Subg.Jungermannia Subg.Liochlaena (Nees) S. Arnell. Nach dem Verfasser gehören zu diesem Subgenus nur zwei Arten,J. leiantha Grolle undJ. subulata Evans.     

3.偶联膜的组成和功能

在第2章中,我们已经了解到,构成呼吸作用的氧化一还原反应,是在严格规定的顺序中进行的。从这一方面来说,它们类似于糖酵解、三羧酸循环或脂肪酸氧化循环的多酶途径。然而,又与这些过程不同,呼吸作用和氧化磷酸化是完全与膜相结合的,它们发生于需氧性真核生物的细胞线粒体内膜中,以及细菌的原生质膜中。由于这些膜将呼吸与ATP的合成(以及其它耗能反应)相偶联,因此,通常称     

Modified Nucleosides. II.1 Economical Synthesis of 2′,3′-Dideoxycytidine

Abstract

An economical two pot synthesis of 2′,3′-dideoxycytidine (2) from N⁴-acetyl-cytidine (4) has been developed. The key feature of this sequence is the in situ reductive elimination of a mixture of 1-(3-bromo-3-deoxy-2,5-di-O-acetyl-β-D-xylofuranosyl)-N⁴-acetylcytosine (5) and 1-(2-bromo-3-deoxy-3,5-di-O-acetyl-β-D-arabinofuranosyl)-N⁴-acetylcytosine (6) and subsequent hydrogenation of the resultant olefin over palladised charcoal.