Accelerated Hantzsch electrospray synthesis with temporal control of reaction intermediates
Accelerated Hantzsch electrospray synthesis with temporal control of reaction intermediates
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DOI：
10.1039/c4sc02436b
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发表时间：
2015-01-01
期刊：
影响因子：
8.4
通讯作者：
Cooks, R. Graham
中科院分区：
文献类型：
--
作者：
Bain, Ryan M.;Pulliam, Christopher J.;Cooks, R. Graham
复杂的化学反应可以在毫秒级的时间尺度上在电喷雾液滴中发生。以这种方式研究了1，4-二氢吡啶的Hantzsch合成，使用在线质谱分析来优化条件并表征产物混合物。改变纳米喷雾源和MS入口之间的距离允许探索作为液滴飞行时间的函数的反应进程。带电微滴的去溶剂化与随着距离的增加从起始材料到中间体并最终到产物的转化相关联。在线实验的结果需要终止步骤，该终止步骤不连续地完成去溶剂化过程，并允许所产生的气态离子用于表征系统在特定时间的状态。观察到的中间体对应于已知在本体溶液相反应中发生的那些。喷雾反应混合物的离线收集允许从单个喷雾器回收250 mg h（-1）的所需反应产物，允许通过NMR和其它标准方法表征。描述了加速反应的薄膜版本，并且它可以通过收集表面的温度来控制。
Complex chemical reactions can occur in electrosprayed droplets on the millisecond time scale. The Hantzsch synthesis of 1,4-dihydropyridines was studied in this way using on-line mass spectral analysis to optimize conditions and characterize the product mixture. Changing the distance between the nanospray source and the MS inlet allowed exploration of reaction progress as a function of droplet time-of-flight. Desolvation of the charged microdroplets is associated with transformation from starting material to intermediates and eventually to product as the distance is increased. Results of the on-line experiments require a termination step that discontinuously completes the desolvation process and allows the generated gaseous ions to be used to characterize the state of the system at a particular time. The intermediates seen correspond to those known to occur in the bulk solution-phase reaction. Offline collection of the sprayed reaction mixture allowed the recovery of 250 mg h(-1) of desired reaction product from a single sprayer, permitting characterization by NMR and other standard methods. A thin film version of the accelerated reaction is described and it could be controlled through the temperature of the collection surface.