Indole and its analogs are a very important class of compounds in heterocyclic compounds. In 1866, Adolf von Bayer reduced the oxindole with zinc powder to obtain indole. In 1869, he assumed the structure of indole, which is still recognized by everyone today. Until the end of the 19th century, certain indole compounds were only treated as important dyes. In the 1930s, people's interest in indole gradually increased, because indole appeared as a core group in many important alkaloids, such as tryptophan and phytohormones, until now research on indole Very active.
