Organic Syntheses, CV 5, 206
Submitted by D. C. Nonhebel
1
Checked by R. B. Greenwald and E. J. Corey.
1. Procedure
In a dry,
1-l., two-necked flask, equipped with a
mechanical stirrer and a
reflux condenser fitted with a
drying tube, are placed
17.8 g. (0.100 mole) of anthracene (Note
1),
27.2 g. (0.202 mole) of anhydrous cupric chloride (Note
2), and
500 ml. of carbon tetrachloride (Note
3). The reaction mixture is stirred and heated under reflux for 18–24 hours. The brown
cupric chloride is gradually converted to white
cuprous chloride, and
hydrogen chloride is gradually evolved. At the end of the reaction the
cuprous chloride is removed by filtration, and the
carbon tetrachloride solution is passed through a
35-mm. Chromatographic column filled with
200 g. of alumina (Note
4). The column is eluted with
400 ml. of carbon tetrachloride. The combined eluates are evaporated to dryness to give
19–21 g. (
89–99%) of
9-chloroanthracene as a lemon-yellow solid, m.p.
102–104° (Note
5). Crystallization of the product from
petroleum ether (b.p.
60–80°) gives
16–17 g. (
75–80%) of
9-chloroanthracene as yellow needles, m.p.
104–106°.
2. Notes
4.
Merck alumina or Spence Type H alumina was used.
3. Discussion
The method outlined can be applied to the preparation in better than 90% yield of the 10-chloro derivatives of 9-alkyl-,
6 9-aryl-,
6 and 9-halogenoanthracenes.
7 For the less reactive substrates
chlorobenzene should be used as solvent. This is the only satisfactory procedure for the preparation of
9-bromo-10-chloroanthracene.
7 Other methods of chlorination lead to mixtures of the desired compound and
9,10-dichloroanthracene.
Pyrene can likewise be converted to
1-chloropyrene (
90% yield).
8 Analogous procedures with
cupric bromide lead to the brominated compounds in similar high yields.
Copyright © 1921-2002, Organic Syntheses, Inc. All Rights Reserved