Selected 2,6-(disubstituted)purine 2',3'-didehydro-2',3'-dideoxynucleosides and 2',3'-dideoxynucleosides were prepared and evaluated. Treatment of 5'-protected ribonucleosides with phenoxythiocarbonyl chloride and 4-(dimethylamino)pyridine, or under Schotten-Baumann conditions, gave high yields of 2',3'-O-thionocarbonates that underwent Corey-Winter elimination. Treatment of unprotected ribonuc...

In the development of the mature rabbit erythrocyte from the reticulocyte, the capacity for the synthesis de novo of the purine ring in vitro is lost (2, 3). The mature rabbit erythrocyte, however, does retain a portion of the biosynthetic pathway de novo, as evidenced by its utilization of 5-amino-1-ribosylWimidazolecarboxamide and sodium formate-Cl4 for the formation of inosinic acid (4). The...

Radiomimetic substances are drugs producing similar symptoms in living organisms as ionising radiation does. They constitute a special subgroup of carcinogen, mutagen, teratogen compounds; their common characteristic is to cause DNA breaks and/or inhibit repair. Mustard gas and its derivatives – alkylating agents were the first known group radiomimetic substances, later, it was observed, that s...

Transient precursor states are often experimentally observed for molecules adsorbing on surfaces. However, such precursor states are typically rather short-lived, quickly yielding to more stable adsorption configurations. Here we employ first-principles calculations to systematically explore the interaction mechanism for benzene derivatives on metal surfaces, enabling us to selectively tune the...

Studies on nucleic acid metabolism often require the analytical separation of nucleic acid derivatives and are facilitated by chromatographic methods which are rapid and convenient. Column chromatography on ion exchange resins (1)) paper chromatography (2)) and paper electrophoresis (3) are among the methods used routinely for such separations. Even though these techniques have been employed wi...

Five experiments were carried out to extend knowledge of purine metabolism in the camel (Camelus dromedarius) and to establish a model to enable microbial protein outflow from the forestomachs to be estimated from the urinary excretion of purine derivatives (PD; i.e. xanthine, hypoxanthine, uric acid, allantoin). In experiment 1, four camels were fasted for five consecutive days to enable endog...

Rabbi ts immunized with purin-6-oyl-protein conjugates form antibodies with purine specificity. These antibodies are capable of fixing complement (C t) in the presence of thermally denatured deoxyribonucleic acid (DNA). This reaction was found to be specifically inhibited by purines and purine derivatives (1). Since the purines in D N A are linked to the deoxyribose-phosphate "backbone" a t the...