SYNTHESIS OF VERY HIGH SPECIFIC ACTIVITY N TRITIOACETOXYPHTHALIMIDE: TRITIUM NMR

N-三硫代乙酰氧基邻苯二甲酰亚胺作为一种高效的 乙酰化试剂鼓励我们研究增加 甲基的同位素含量。一个合适的前驱是 可用D2气体进行氢脱卤化的二氯乙酸和 Pd/Al_2O_3在氢氧化钠溶液中。过滤后的醋酸盐为 然后酸化，用乙醚提取醋酸。添加 N-羟基邻苯二甲酰亚胺在四氢呋喃中，然后在二氯甲烷中生成DCC N-二氢乙酰氧基邻苯二甲酰亚胺，产率42%，每个氢原子2.3个。 分子。与这种方法相关的几个问题仍有待解决 解决：1.从盐中形成游离酸 (酸化)。PH值必须在4到5之间才能避免交换， 因此失去了标签。2.轻松高效地与 N-羟基邻苯二甲酰亚胺-催化裂化高效联轴器需要干燥 空灵的解决方案。

The usefulness of N-tritioacetoxyphthalimide as an efficient acetylation reagent encouraged us to investigate methods to increase the isotopic content of the methyl group. An appropriate precursor is dichloroacetic acid which can be deuteriodehalogenated with D2 gas and Pd/Al2O3 in a sodium hydroxide solution. The filtered acetate salt is then acidified and the acetic acid extracted with ether. Addition of N-hydroxyphthalimide in THF, then DCC in methylene chloride produces N-deuterioacetoxyphthalimide in 42% yield with 2.3 deuterium atoms per molecule. Several problems associated with this method remain to be resolved: 1. Formation of the free acid from the salt (acidification). The pH must be between 4 and 5 to avoid exchange, and therefore loss of label. 2. Ease and efficiency of coupling with N-Hydroxyphthalimide - high efficiency coupling in DCC requires a dry ethereal solution.