核苷研究2: 苄基糖核苷的立体选择性合成

1-(2, 3, 4, 6-O-四苄基吡喃糖基)-三氟乙酸酯或三氯乙酸酯在无水四氯化锡存在下与一些具有代表性的硅醚保护的碱基或者含氮杂环化合物反应, 合成了一系列新的苄基糖苷。对三氟乙酰氧基、三氯乙酰氧基作为新的离去基在核苷合成中的反应活性、立体选择性和反应收率进行了讨论。     

Synthesis of 2-S-dioxo isosteres of purine and pyrimidine nucleosides. II

The preparation of glucosyl and ribosyl derivatives of 3,4,5-triamino-2H-1,2,6-thiadiazine 1,1-dioxide ( 2 ), 7-amino-4H-furazano[3,4-c]- and 7-amino-1H, 4H-imidazo[2,3-c][1,2,6]thiadiazine 5,5-dioxide ( 3 and 4 respectively) is described. Different synthetic approaches have been used.     

Studies on oxygen determination in organic microanalysis. II. On the microanalysis of oxygen by decrease in the quantity of anhydro-iodic acid

Summary Oxygen in organic compounds is determined by means of the decrease in weight of anhydro-iodic acid. Anhydro-iodic acid is stable in air and can be used for a long time. Satisfactory analyses are obtained.

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Zusammenfassung Sauerstoff kann in organischen Verbindungen durch Messung des Gewichtsverlustes der Anhydrojodsäure bestimmt werden. Diese ist an der Luft beständig und bleibt lange Zeit verwendungsfähig. Zufriedenstellende Analysenergebnisse werden erhalten.

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Résumé Le dosage de l'oxygène dans les composés organiques est effectué par la détermination de la diminution de poids de l'acide anhydroiodique. L'acide anhydroiodique est stable à l'air et peut être employé pendant des temps très longs. Des résultats satisfaisants ont été obtenus par les auteurs.

     

Analysis of urinary nucleosides. II. Comparison of mass spectrometric methods for the analysis of urinary nucleosides

Qualitative and quantitative analyses of urinary nucleosides have diagnostic potential as tumour markers. We have developed separation techniques linked to mass spectrometric detection in order to overcome the problems associated with past identification and quantitation methods. The three methods of analysis utilised were: gas chromatography/mass spectrometry (GC/MS), high-performance liquid chromatography/ion-trap mass spectrometry (HPLC/ITMS) and capillary liquid chromatography/triple quadrupole mass spectrometry (CapLC/TQMS). Here we compare the relative effectiveness of each of the techniques for subsequent application in the systematic study of urinary nucleoside profiles in cancer patients. All three methods proved to be valuable techniques for such urinary nucleoside analyses, and a combination rather than one single choice is concluded as the ideal.     

Singlet oxygen oxidation of polynorbornene (Part II)

Polynorbornene is a polymer susceptible to oxidation by singlet oxygen (¹O₂, ¹Δ_g) generated by a microwave method or in dye photosensitised reactions. Reaction of singlet oxygen with polynorbornene yields hydroperoxides. The photochemical decomposition of these hydroperoxides produces polymer oxy radicals. Polymer chain scission is a result of β-scission of the polymer oxy radicals.