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Org. Synth. 1948, 28, 28
DOI: 10.15227/orgsyn.028.0028
m-CHLOROPHENYLMETHYLCARBINOL
[Benzyl alcohol, m-chloro-α-methyl-]
Submitted by C. G. Overberger, J. H. Saunders, R. E. Allen, and Robert Gander.
Checked by Arthur C. Cope and Theodore T. Foster.
1. Procedure
A dry 2-l. three-necked round-bottomed flask is equipped with a sealed stirrer, a 500-ml. dropping funnel (Note 1), and an efficient reflux condenser attached to a calcium chloride tube. In the flask are placed 29.1 g. (1.2 gram atoms) of magnesium turnings, a crystal of iodine, and about 50 ml. of dry ether. A solution of 229 g. (1.2 moles) of m-bromochlorobenzene (Note 2) in 850 ml. of dry ether is added with stirring at a rate which maintains rapid refluxing. The reaction begins after 20–50 ml. of the ether solution is added (Note 3), and the addition requires 1–3 hours. The mixture is stirred and heated on the steam bath under reflux for 1 hour after all the m-bromochlorobenzene has been added.
A cooled solution of 60 g. (1.365 moles) of freshly distilled acetaldehyde in 200 ml. of dry ether (Note 4) is added through the dropping funnel during 2–3.5 hours, as rapidly as the condenser capacity permits. The mixture is stirred and heated under reflux for 1 hour after the addition is completed.
The reaction mixture is cooled in ice, and the addition compound is decomposed by adding dropwise with stirring 185 ml. of a 25% solution of ammonium chloride in water (Note 5). The ether solution becomes clear, and the salts separate as a cake. The ether solution is decanted, combined with 150 ml. of ether that has been used to rinse the salt cake, and dried over anhydrous magnesium sulfate. After removal of the ether the product is distilled under reduced pressure to give 154.5–164.5 g. (82.5–88%) of m-chlorophenylmethylcarbinol boiling at 99–104°/4 mm.; nD25 1.5405 (Note 6).
2. Notes
1. It is convenient to use a Hershberg stirrer with a rubber slip seal protected from ether vapor with a short water-cooled condenser. The dropping funnel may be connected to the flask through an extension tube to prevent clogging, which occurs if the Grignard reagent comes in contact with the acetaldehyde in the tip of the funnel.
2. m-Bromochlorobenzene was prepared according to p. 185. It may be purchased from the Eastman Kodak Company.
3. If the reaction does not begin spontaneously, the mixture should be heated under reflux until the reaction starts before more than 50 ml. of the m-bromochlorobenzene solution is added.
4. The solution is cooled to prevent loss of acetaldehyde by vaporization. Commercial acetaldehyde may be redistilled just before it is used, or acetaldehyde may be prepared by depolymerization of paraldehyde.1
5. The submitters state that the complex may be decomposed by pouring the reaction mixture onto 1 kg. of crushed ice to which 50 ml. of concentrated sulfuric acid has been added. The ether layer is separated, combined with two 100-ml. ether extracts of the aqueous layer, and washed with three 250-ml. portions of water, one 250-ml. portion of 10% sodium carbonate solution, and finally with 250 ml. of water.
6. The same general method (including the procedure of (Note 5)) has been used by the submitters to prepare the following substituted phenylmethylcarbinols:

Carbinol

Boiling Point

% Yield


m-Trifluoromethylphenylmethylcarbinol

100–102°/17 mm.

83

m-Methylphenylmethylcarbinol

103–105°/6 mm.

71

m-tert-Butylphenylmethylcarbinol

130–134°/17 mm.

56


An alternative preparation of similar carbinols, consisting in the reaction of methylmagnesium iodide with a substituted benzaldehyde, is advantageous when the aromatic aldehyde is available. The following carbinols have been prepared by the submitters in that way:

Aldehyde

Carbinol

Boiling Point

% Yield


p-Chlorobenzaldehyde [Heyden Chemical Corporation; Org. Syntheses Coll. Vol. 2, 133 (1943)]

p-Chlorophenylmethylcarbinol

98–100°/4.5 mm.

59

o-Chlorobenzaldehyde (Heyden Chemical Corporation)

o-Chlorophenylmethylcarbinol

94°/4 mm.

69

o-Bromobenzaldehyde

o-Bromophenylmethylcarbinol

102–105°/2–3 mm.

73

m-Bromobenzaldehyde

m-Bromophenylmethylcarbinol

105–110°/2–3 mm.

74

p-Bromobenzaldehyde [Org. Syntheses Coll. Vol. 2, 89, 442 (1943)]

p-Bromophenylmethylcarbinol

90°/1 mm.

64

2,3-Dichlorobenzaldehyde

2,3-Dichlorophenylmethylcarbinol

112–113°/2 mm. m.p. 55–57°

76

2,4-Dichlorobenzaldehyde (Heyden Chemical Corporation)

2,4-Dichlorophenylmethylcarbinol

125–126°/7 mm.

62

2,6-Dichlorobenzaldehyde (Eastman Kodak Company)

2,6-Dichlorophenylmethylcarbinol

104–107°/2.5 mm.

89

3,5-Dichlorobenzaldehyde

3,5-Dichlorophenylmethylcarbinol

126°/4 mm.

69

3,4-Dichlorobenzaldehyde (Heyden Chemical Corporation)

3,4-Dichlorophenylmethylcarbinol

125–130°/3–4 mm.

73


3. Discussion
This procedure is adapted from the preparation described by Marvel and Schertz.2 m-Chlorophenylmethylcarbinol also has been prepared from m-chlorobenzaldehyde and methylmagnesium iodide,3,4,5 and by the reduction of m-chloroacetophenone in the presence of copper chromite.6
This preparation is referenced from:

References and Notes
  1. Org. Syntheses Coll. Vol. 2, 407 (1943).
  2. Marvel and Schertz, J. Am. Chem. Soc., 65, 2054 (1943).
  3. Lock and Bock, Ber., 70, 916 (1937).
  4. Brooks, J. Am. Chem. Soc., 66, 1295 (1944).
  5. Ushakov and Matuzov, J. Gen. Chem. U.S.S.R., 14, 120 (1944) [C. A., 39, 916 (1945)].
  6. Emerson and Lucas, J. Am. Chem. Soc., 70, 1180 (1948).

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

acetaldehyde (75-07-0)

sulfuric acid (7664-93-9)

ether (60-29-7)

ammonium chloride (12125-02-9)

magnesium turnings (7439-95-4)

sodium carbonate (497-19-8)

benzaldehyde (100-52-7)

iodine (7553-56-2)

methylmagnesium iodide (917-64-6)

magnesium sulfate (7487-88-9)

COPPER CHROMITE

2,3-Dichlorobenzaldehyde (6334-18-5)

2,3-Dichlorophenylmethylcarbinol

2,4-Dichlorobenzaldehyde (874-42-0)

2,4-Dichlorophenylmethylcarbinol (81156-68-5)

2,6-Dichlorobenzaldehyde (83-38-5)

2,6-Dichlorophenylmethylcarbinol

3,5-Dichlorobenzaldehyde (10203-08-4)

3,5-Dichlorophenylmethylcarbinol

3,4-Dichlorobenzaldehyde (6287-38-3)

3,4-Dichlorophenylmethylcarbinol

m-Bromobenzaldehyde (3132-99-8)

m-Chlorobenzaldehyde (587-04-2)

p-Chlorobenzaldehyde (104-88-1)

o-chlorobenzaldehyde (89-98-5)

p-Bromobenzaldehyde (1122-91-4)

m-bromochlorobenzene (108-37-2)

m-Chlorophenylmethylcarbinol (5182-44-5)

Benzyl alcohol, m-chloro-α-methyl- (6939-95-3)

m-Trifluoromethylphenylmethylcarbinol (455-01-6)

m-Methylphenylmethylcarbinol (1875-89-4)

m-tert-Butylphenylmethylcarbinol

p-Chlorophenylmethylcarbinol (1875-88-3)

o-Chlorophenylmethylcarbinol (19819-95-5)

o-Bromobenzaldehyde (6630-33-7)

o-Bromophenylmethylcarbinol (1074-16-4)

m-Bromophenylmethylcarbinol (28229-69-8)

p-Bromophenylmethylcarbinol (4654-39-1)

m-chloroacetophenone (99-02-5)

paraldehyde (123-53-7)