Haworth synthesis
The Haworth synthesis enables the production of phenanthrene , an aromatic hydrocarbon. It was presented in 1932 by the English chemist Robert Downs Haworth (1898–1990).
The following synthesis steps are described in the literature:
In the first step naphthalene 1 by means of Friedel-Crafts acylation by succinic anhydride 2 acylated. The resulting γ-keto acid 3 is then reduced by means of Clemmensen reduction with zinc amalgam and hydrochloric acid , so that the naphthalene derivative 4 is formed. By adding sulfuric acid , water is then split off . A subsequent intramolecolar electrophilic substitution produces ketone 5 . Another Clemmensen reduction then follows, with the tricyclic hydrocarbon 6 being formed. The dehydration of 6 with selenium provides phenanthrene 7 .
Individual evidence
- ^ RD Haworth: Syntheses of alkylphenanthrenes. In: Journal of the Chemical Society . 1932, p. 1125, doi: 10.1039 / JR9320001125 .
- ↑ E. Broad Maier and G. Jung: Organic Chemistry. Georg Thieme, 2012, ISBN 9783135415079 , p. 183.
- ^ Zerong Wang: Comprehensive Organic Name Reactions and Reagents. Wiley, 2010, ISBN 9780470638859 , pp. 1342-1343, doi: 10.1002 / 9780470638859 .