Studies of Crystalline Vitamin B1. III. Cleavage of Vitamin with Sulfite
Studies of Crystalline Vitamin B1. III. Cleavage of Vitamin with Sulfite
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晶体维生素 B1 的研究。
DOI：
10.1021/ja01306a044
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发表时间：
1935
影响因子：
15
通讯作者：
E. R. Buchman
中科院分区：
文献类型：
--
作者：
Rob Williams;R. Waterman;J. C. Keresztesy;E. R. Buchman
1933 年秋天，当我们获得晶体维生素 Bi 供研究时，我们仔细考虑了选择适合揭示其构成事实的裂解反应。这种照顾被认为是必要的，不仅是为了维生素的经济性，而且还因为该物质的不稳定性表明剧烈的处理可能会导致分子中几个点的分裂。这一迹象似乎已被其他人的经验所证实，特别是 Van Veen，2 更常见的氧化和水解试剂会产生多种物质。对我们多年来在维生素分离方面的经验的回顾提供了一个有希望的建议。几年前，有人尝试利用亚硫酸作为大米抛光提取物防止细菌腐烂的防腐剂，结果导致室温下抗神经炎活性迅速完全丧失。在初步实验中，将几毫克结晶维生素溶解在两份亚硫酸钠溶液中，分别调节至pH 1和pH 4后，在室温下在甲苯中静置三十六小时。然后用氧化钡使溶液呈碱性以除去亚硫酸根离子。经多发性神经炎大鼠注射显示，已将pH调节至1的溶液的中和滤液已失去约一半的活性； pH 4 时完全没有活性。此后，我们对维生素的这种反应有了丰富的经验，发现它在 pH 值约为 5 的情况下很容易进行，在此条件下，它在室温下在 24 至 48 小时内完成；根据一次实验，在蒸汽浴温度下，该过程在一小时或更短的时间内完成。使用
When in the fall of 1933 supplies ofcrystalline vitamin Bi became available1 to us for study, careful consideration was given to the choice of cleavage reactions adapted to reveal factsabout its constitution. Such care was considered neces-sary not only for the sake of economy of vitamin but also because the lability of the substance suggested that drastic treatments would probably cause splitting at several points in the molecule. This indication appeared to be confirmed by the experience of others, notably Van Veen, 2 that a miscellany of substances is produced by the more usual oxidative and hydrolytic reagents. A review of our experience extending over many years in connection with isolation of the vitamin offered a promising suggestion. Several years ago an attempt to utilize sulfurous acid as a preservative against bacterial decay of rice polish extracts had led to a very prompt and complete loss of the antineuritic activity at room tempera-ture. In a preliminary experiment, a few milli-grams ofthe crystalline vitamin dissolved in two portions of sodium, sulfite solution were allowed to stand at room temperature under toluene for thirty-six hours after adjustment to pH 1 and pH 4, respectively. The solutions were then made alkaline with baryta to remove sulfite ion. The neutralized filtrate of the solution which had been adjusted to pH 1 had lost about half its activity as shown by injection of polyneuritic rats; that at pH 4 was quite devoid of activity. We have since had considerable experience with this reaction of the vitamin and find that it proceeds readily at about pH 5, under which conditions it is complete at room temperature in twenty-four to forty-eight hours; at steam-bath temperature it is complete in an hour or less according to a single experiment. The use of