Baeyer–Drewsen indigo synthesis explained

The Baeyer–Drewsen indigo synthesis (1882) is an organic reaction in which indigo is prepared from 2-nitrobenzaldehyde and acetone^{[1] [2]} The reaction was developed by von Baeyer and in 1880 to produce the first synthetic indigo at laboratory scale. This procedure is not used at industrial scale.^[3]

The reaction is classified as an aldol condensation. As a practical route to indigo, this method was displaced by routes from aniline.^[4]

Note

In the English literature this reaction is sometimes called Baeyer–Drewson reaction, although the author of the original paper was spelled Drewsen.

External links

• Lab Manual
• Lab-synthesis of indigo

Notes and References

1. Darstellung von Indigblau aus Orthonitrobenzaldehyd . Adolf Baeyer, Viggo Drewsen . . 15 . 2 . 2856–2864 . 1882 . 10.1002/cber.188201502274 .
2. Indigo – 100 Jahre industrielle Synthese . Helmut Schmidt . . 31 . 3 . 121–128 . 1997 . 10.1002/ciuz.19970310304 .
3. Web site: Johannes Pfleger, Chemist . dead . https://web.archive.org/web/20140524025035/https://history.evonik.com/sites/geschichte/en/personalities/pfleger-johannes/pages/default.aspx . 2014-05-24 . 2022-12-04 . Evonik Industries.
4. Elmar Steingruber "Indigo and Indigo Colorants" Ullmann's Encyclopedia of Industrial Chemistry 2004, Wiley-VCH, Weinheim.