Isbell H S, Frush H L, Holt N B, Moyer J D
J Res Natl Bur Stand A Phys Chem. 1960 Mar-Apr;64A(2):177-180. doi: 10.6028/jres.064A.018. Epub 1960 Apr 1.
In a new method for preparing aldoses labeled with tritium at carbon 1, the aldonic lactone is reduced with lithium borohydride- in pyridine solution. The method is suitable for preparing aldoses- having high specific activities. The crude product contains a substantial proportion of the corresponding alditol-, but the pure aldose- is readily separated by fractional recrystallization or paper chromotography. By means of an isotope-dilution technique, yields were determined for the following aldoses- and the corresponding alditols-: d-arabinose-, d-xylose-, d-ribose-, d-glucose-, d-galactose-, d-mannose-, l-rhamnose-, maltose-, and lactose-. These labeled materials were also prepared by reducing the corresponding lactones with sodium amalgam in tritiated water. Although this latter method is not suitable for preparing labeled aldoses of high specific activity, the products are more readily purified than those obtained by reducing the lactones with lithium borohydride-. d-Glucose-, obtained by each of these reduction methods, was oxidized with bromine, and the resulting d-gluconic acid was found to be nonradioactive. Hence, in the samples oxidized, tritium was present only at C1. An apparatus used tor reclaiming tritiated water by freeze-drying is depicted; it incorporates an efficient device for trapping entrained solids or liquids.
在一种制备在碳1位标记有氚的醛糖的新方法中，醛糖酸内酯在吡啶溶液中用硼氢化锂还原。该方法适用于制备具有高比活度的醛糖。粗产物含有相当比例的相应糖醇，但纯醛糖可通过分级重结晶或纸色谱法轻松分离。通过同位素稀释技术，测定了以下醛糖及其相应糖醇的产率：d-阿拉伯糖、d-木糖、d-核糖、d-葡萄糖、d-半乳糖、d-甘露糖、l-鼠李糖、麦芽糖和乳糖。这些标记物也通过在氚化水中用钠汞齐还原相应内酯来制备。虽然后一种方法不适用于制备高比活度的标记醛糖，但其产物比用硼氢化锂还原内酯得到的产物更容易纯化。通过这些还原方法中的每一种得到的d-葡萄糖用溴氧化，发现所得的d-葡萄糖酸无放射性。因此，在氧化的样品中，氚仅存在于C1位。描述了一种用于通过冷冻干燥回收氚化水的装置；它包含一个用于捕集夹带的固体或液体的高效装置。
