Org. Synth. 1967, 47, 1
DOI: 10.15227/orgsyn.047.0001
[Benzaldehyde, 2,4,6-trimethyl-]
Submitted by A. Rieche, H. Gross, and E. Höft1.
Checked by G. N. Taylor and K. B. Wiberg.
1. Procedure
A solution of 72 g. (0.60 mole) of mesitylene in 375 ml. of dry methylene chloride is placed in a 1-l. three-necked flask equipped with a reflux condenser, a stirrer, and a dropping funnel. The solution is cooled in an ice bath, and 190 g. (110 ml., 1.0 mole) of titanium tetrachloride is added over a period of 3 minutes. While the solution is stirred and cooled, 57.5 g. (0.5 mole) of dichloromethyl methyl ether2 is added dropwise over a 25-minute period. The reaction begins (as indicated by evolution of hydrogen chloride) when the first drop of chloro ether is added. After the addition is complete, the mixture is stirred for 5 minutes in the ice bath, for 30 minutes without cooling, and for 15 minutes at 35°.
The reaction mixture is poured into a separatory funnel containing about 0.5 kg. of crushed ice and is shaken thoroughly. The organic layer is separated, and the aqueous solution is extracted with two 50-ml. portions of methylene chloride. The combined organic solution is washed three times with 75-ml. portions of water. A crystal of hydroquinone is added to the methylene chloride solution (Note 1) which is then dried over anhydrous sodium sulfate. After evaporation of the solvent, the residue is distilled to give the crude product, b.p. 68–74° (0.9 mm.). After redistillation there is obtained 60–66 g. (81–89%) of mesitaldehyde; b.p. 113–115° (11 mm.), n20D 1.5538.
2. Notes
1. Hydroquinone retards the autoxidation of the aldehyde.
3. Discussion
Mesitaldehyde may be prepared from mesitylmagnesium bromide by the reaction with orthoformate esters3 or ethoxymethyleneaniline;3 from acetylmesitylene by oxidation with potassium permanganate;4 from mesitoyl chloride by reduction;5 from mesityllithum by the reaction with iron pentacarbonyl;6 and from mesitylene by treatment with formyl fluoride and boron trifluoride,7 by treatment with carbon monoxide, hydrogen chloride, and aluminum chloride,8 or by various applications of the Gatterman synthesis.9,10,11
4. Merits of the Preparation
The preparation of mesitaldehyde is an example of a generally applicable method for the preparation of aromatic aldehydes by treatment of aromatic compounds with dichloromethyl methyl ether.12 Aldehydes derived from polynuclear aromatic compounds,12,13 phenols,14 phenol ethers,12 and hetero-aromatic compounds12 are also obtained using this procedure. In addition, colchicine derivatives have been formylated15 by means of dichloromethyl methyl ether.
This preparation is referenced from:

References and Notes
  1. Institute for Organic Chemistry of the German Academy of Sciences at Berlin, Berlin-Adlershof, Germany.
  2. H. Gross, A. Rieche, E. Höft, and E. Beyer, this volume, p. 365.
  3. L. I. Smith and J. Nichols, J. Org. Chem., 6, 489 (1941).
  4. R. P. Barnes, C. I. Pierce, and C. C. Cochrane, J. Am. Chem. Soc., 62, 1084 (1940).
  5. R. P. Barnes, Org. Syntheses, Coll. Vol. 3, 551 (1955).
  6. M. Ryang, I. Rhee, and S. Tsutsumi, Bull. Chem. Soc. Japan, 37, 341 (1964).
  7. G. A. Olah and S. J. Kuhn, J. Am. Chem. Soc., 82, 2380 (1960).
  8. L. Gattermann, Ann., 347, 347 (1906).
  9. R. C. Fuson, E. C. Horning, S. P. Rowland, and M. L. Ward, Org. Syntheses, Coll. Vol. 3, 549 (1955).
  10. L. E. Hinkel, E. E. Ayling, and W. H. Morgan, J. Chem. Soc., 2793 (1932).
  11. L. E. Hinkel, E. E. Ayling, and J. H. Beynon, J. Chem. Soc., 339 (1936).
  12. A. Rieche, H. Gross, and E. Höft, Ber., 93, 88 (1960).
  13. H. Reimlinger, J. P. Golstein, J. Jadot, and P. Jung, Ber., 97, 349 (1964).
  14. H. Gross, A. Rieche, and G. Matthey, Ber., 96, 308 (1963).
  15. G. Muller, A. B. Font, and R. Bardoneschi, Ann., 662, 105 (1963).

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

hydrogen chloride (7647-01-0)

carbon monoxide (630-08-0)

hydroquinone (123-31-9)

potassium permanganate (7722-64-7)

sodium sulfate (7757-82-6)

aluminum chloride (3495-54-3)

Mesitylene (108-67-8)

methylene chloride (75-09-2)

boron trifluoride (7637-07-2)

ethoxymethyleneaniline (6780-49-0)

Benzaldehyde, 2,4,6-trimethyl- (487-68-3)

Mesitoyl chloride (938-18-1)

mesitylmagnesium bromide (2633-66-1)

titanium tetrachloride (7550-45-0)

Dichloromethyl methyl ether (4885-02-3)


iron pentacarbonyl

formyl fluoride (1493-02-3)