SYNTHESIS OF DI-TERT-BUTYL METHYLENEMALONATE, A STERICALLY HINDERED 1,1-DICARBONYL ALKENE
SYNTHESIS OF DI-TERT-BUTYL METHYLENEMALONATE, A STERICALLY HINDERED 1,1-DICARBONYL ALKENE
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DOI：
10.1021/jo00168a061
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发表时间：
1983-01-01
影响因子：
3.6
通讯作者：
WONG, J
中科院分区：
文献类型：
--
作者：
BALLESTEROS, P;ROBERTS, BW;WONG, J
以这种方式得到的5的核磁共振光谱分析表明，存在少量的起始酯1和他（羟甲基）衍生物8 （vide infra）作为污染物。后者通过第二次蒸馏除去，得到含有微量1的5的总收率为53%。根据我们的经验，1的存在不会对5的反应产生干扰，也没有必要进一步纯化。5是一种流动的、透明的液体，其稳定性与较简单的丙二酸亚甲酯形成鲜明对比。因此，新鲜制备的样品在室温下保存了4周，XH核磁共振波谱显示没有明显的变化。然而，罕见的是，一些样品已经发展成
NMR spectroscopic analysis of 5 obtained in this fashion indicated the presence of small amounts of starting ester 1 and bis (hydroxymethyl) derivative 8 (vide infra) as contaminants. The latter was removed by a second distillation to give an overall yield of 53% of 5 containing a trace of 1. In our experience, the presence of 1 has presented no interference to reactions of 5, and there has been no necessity for further purification. 5 was obtained as a mobile, clear liquid, the stability of which contrasts sharply with that of simpler methylene-malonate esters. Thus freshly prepared samples have been kept at room temperature for up to 4 weeks with no observable change as indicated by XH NMR spectroscopy. Infrequently, however, some samples have developed a