The front cover shows that three different pyrrole derivatives can be obtained from the same starting reagents. The reaction is easily controlled by 1) the ratio of the starting reagents, 2) the amount of alkali, and 3) the degree of dilution. This process can be compared with playing the balalaika (a Russian folk instrument), where, by using just three strings, it is possible to produce beautiful melodies from the same notes. The three strings are associated with the three parameters, and the notes are the starting reagents. The sheets with quantum‐chemical calculations symbolize that the experimental work is based on theoretical investigations. More details are given in the Full Paper by N. M. Vitkovskaya and co‐workers (DOI: 10.1002/cplu.201900407).

中文翻译：

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1H-吡咯-2-基甲醇和炔丙基氯化物在碱促进下生成的吡咯并1,4-恶嗪基团的形成：理论和实验研究

封面显示，可以从相同的起始试剂中获得三种不同的吡咯衍生物。通过1）起始试剂的比例，2）碱的量和3）稀释度可以很容易地控制反应。可以将这种过程与演奏巴拉莱卡（一种俄罗斯民间乐器）进行比较，在这种情况下，只需使用三个琴弦，就可以用相同的音符产生优美的旋律。这三个字符串与这三个参数相关联，并且注释是起始试剂。带有量子化学计算的工作表象征着实验工作是基于理论研究的。N.M. Vitkovskaya及其同事在完整论文中提供了更多详细信息（DOI：10.1002 / cplu.201900407）。