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Org. Synth. 1952, 32, 25
DOI: 10.15227/orgsyn.032.0025
p-CHLOROPHENYL SALICYLATE
[Salicylic acid, p-chlorophenyl ester]
Submitted by Norman G. Gaylord and P. M. Kamath1.
Checked by R. T. Arnold and J. John Brezinski.
1. Procedure
To a mixture of 138.1 g. (1 mole) of salicyclic acid and 128.6 g. (1 mole) of p-chlorophenol in a 2-l. round-bottomed flask fitted with a thermometer reaching to the bottom of the flask and a reflux condenser with a drying tube (Note 1) is added 58.3 g. (0.38 mole) of phosphorus oxychloride. The mixture is heated with occasional swirling, and the temperature is maintained at 75–80°. At the end of 4 hours the reactants have been reduced to a molten mass, and this is poured slowly, with vigorous stirring, into a solution of 120 g. of sodium carbonate in 800 ml. of water. The precipitated ester is collected on a filter and washed with four 200-ml. portions of water. The yield of crude, air-dried, p-chlorophenyl salicylate is 174–189 g. (70–76%); m.p. 65–66°. Recrystallization from absolute ethanol yields 136–154 g. (55–62%) of pure product; m.p. 69.5–70.5°. A second crop may be obtained by concentration of the filtrate from the first crop or by the addition of water (Note 2).
2. Notes
1. It is advisable to attach the drying tube to a water trap2 in order to prevent the escape of hydrogen chloride into the atmosphere.
2. The above method has been used in the preparation of other substituted phenyl salicylates to give the following yields of recrystallized products with the indicated melting points.

Yield, (%)

M.P.


o-Chlorophenyl ester

67

52.0–52.4°

p-Nitrophenyl ester

53

151.5–151.9°

p-tert-Butylphenyl ester

42

63.0–63.4°

p-Phenylphenyl ester

66

109.2–109.6°

o-Phenylphenyl ester

70

89.2–89.5°


These esters, with the exception of the p-nitrophenyl derivative, can be recrystallized from absolute ethanol. The nitro compound is recrystallized from dioxane.
3. Discussion
Substituted phenyl salicylates can be prepared by heating salicylic acid and the appropriate phenol in the presence of phosphorus oxychloride,3,4,5 phosphorus trichloride,4,5 phosphorus pentachloride,4,6 phosgene,4 or thionyl chloride,4 or by heating the phenol and salol.7

References and Notes
  1. Polytechnic Institute of Brooklyn, Brooklyn, New York.
  2. Org. Syntheses Coll. Vol. 1, 97 (1941).
  3. Seifert, J. prakt. Chem., [2] 31, 472 (1885); Nencki and Heyden, Ger. pats. 38,973 [Ber., 20R, 351 (1887)] and 43,713 [Ber., 21R, 554 (1888)]; Walther and Zipper, J. prakt. Chem., [2] 91, 399 (1915); Krauz and Remenec, Collection Czechoslov. Chem. Communs., 1, 610 (1929) [C. A., 24, 1365 (1930)]; Kolloff and Page, J. Am. Chem. Soc., 60, 948 (1938).
  4. Nencki and Heyden, Ger. pat. 70,519 [Ber., 26R, 967 (1893)].
  5. Harris and Christiansen, J. Am. Pharm. Assoc., 24, 553 (1935); U. S. pat. 2,141,172 [C. A., 33, 2655 (1939)].
  6. Tozer and Smiles, J. Chem. Soc., 1938, 1897.
  7. Cohn, J. prakt. Chem., [2] 61, 550 (1900).

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

salicyclic acid

salol

ethanol (64-17-5)

hydrogen chloride (7647-01-0)

phosphorus pentachloride (10026-13-8)

thionyl chloride (7719-09-7)

sodium carbonate (497-19-8)

salicylic acid

Phosphorus Oxychloride (21295-50-1)

phosgene (75-44-5)

phosphorus trichloride (7719-12-2)

dioxane (5703-46-8)

p-chlorophenol (106-48-9)

p-Chlorophenyl salicylate,
Salicylic acid, p-chlorophenyl ester (2944-58-3)

o--Chlorophenyl salicylate

p-Nitrophenyl salicylate

p-tert-Butylphenyl salicylate

p-Phenylphenyl salicylate

o-Phenylphenyl salicylate