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Org. Synth. 1968, 48, 30
DOI: 10.15227/orgsyn.048.0030
3-BROMOPYRENE
[Pyrene, 1-bromo-]
Submitted by W. H. Gumprecht1
Checked by Melvin S. Newman and Stephen Havlicek.
1. Procedure
Caution! Many pyrenes are carcinogens. Contact of the skin with these materials should be avoided.
In a 500-ml., three-necked, round-bottomed flask fitted with a stirrer, a reflux condenser, and a dropping funnel are placed 8.08 g. (0.040 mole) of pyrene (Note 1) and 80 ml. of carbon tetrachloride (Note 2). A solution of 2.0 ml. of bromine (6.24 g., 0.039 mole) (Note 3) in 30 ml. of carbon tetrachloride is added dropwise over a period of 2–3 hours. The resulting orange solution is stirred overnight, washed with three 100-ml. portions of water, and dried over anhydrous calcium chloride. The solvent is removed under reduced pressure, the pale yellow solid residue is dissolved in 10 ml. of benzene, and the benzene solution is treated with a small amount of activated carbon. The filtrate is diluted with 120 ml. of absolute ethanol, and the solution is distilled until about 80–90 ml. of solvent remains and then cooled. The bromopyrene crystallizes as pale yellow flakes, m.p. 93–95°. Additional material of similar melting point is obtained from the mother liquor on concentration. The total yield is 8.5–9.5 g. (78–86%) (Note 4). On recrystallization from benzene-alcohol a colorless product, m.p. 94.5–95.5°, is obtained with little loss.
2. Notes
1. Pyrene, m.p. 151–153°, obtained from Chemicals Division, Union Carbide Chemicals Corp., was used by the submitter. A commercial pyrene obtained from Germany was used by the checkers.
2. A C.P. solvent was used.
3. Reagent grade material was used. Excess bromine is to be avoided, as dibromopyrene can be formed.2
4. The submitter has run this preparation on 80 g. of pyrene with no change in yield.
3. Discussion
This procedure is described by Lock;2 a modification using a small amount of phenol has been published.3 The patent literature discloses the use of a tertiary amine, such as pyridine, and its combination with other solvents for the monobromination of pyrene with elemental bromine.4 Brominating agents, such as N-bromosuccinimide5 and N-bromohydantoins,6 have also been used.
4. Merits of the Preparation
3-Bromopyrene is a precursor of 3-hydroxypyrene.7
This preparation is referenced from:

References and Notes
  1. Contribution No. 334 from the Organic Chemicals Department, E. I. du Pont de Nemours and Company, Wilmington, Delaware 19899.
  2. G. Lock, Ber., 70, 926 (1937).
  3. H. Hock and F. Ernst, Ber., 92, 2732 (1959).
  4. A. Wolfram and W. Schnurr, U.S. Patent 2,094,227 (1937) [C.A., 31, 8550 (1937)].
  5. Ng. Ph. Buu-Hoi and J. Lecocq, Compt. Rend., 226, 87 (1948).
  6. J. F. Salellas and O. O. Orazi, Anales Asoc. Quim. Arg., 39, 175 (1951) [C.A., 47, 2708 (1953)]; R. A. Corral, O. O. Orazi, and J. D. Bonafede, Anales Asoc. Quim. Arg., 45, 151 (1957) [C.A., 53, 342 (1959)].
  7. W. H. Gumprecht, this volume, p. 632.

Appendix
Chemical Abstracts Nomenclature (Collective Index Number);
(Registry Number)

ethanol (64-17-5)

calcium chloride (10043-52-4)

Benzene (71-43-2)

phenol,
benzene-alcohol (108-95-2)

bromine (7726-95-6)

carbon tetrachloride (56-23-5)

carbon (7782-42-5)

pyridine (110-86-1)

pyrene (129-00-0)

N-bromosuccinimide (128-08-5)

3-Bromopyrene,
Pyrene, 1-bromo-,
bromopyrene (1714-29-0)

dibromopyrene

3-Hydroxypyrene (5315-79-7)