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Org. Synth. 1943, 23, 27
DOI: 10.15227/orgsyn.023.0027
β,β-DIMETHYLACRYLIC ACID
[Senecioic acid]
Submitted by Lee Irvin Smith, W. W. Prichard, and Leo J. Spillane.
Checked by Nathan L. Drake and Harry D. Anspon.
1. Procedure
A 5-l. round-bottomed three-necked flask is equipped with a Kyrides sealed stirrer and two long condensers, and the apparatus is so arranged that, if necessary, the exit water from the condensers may be quickly used to cool the flask.
In the flask are placed 200 ml. of dioxane, 100 g. (1.02 moles) of mesityl oxide, and a solution of 4.6 moles of potassium hypochlorite in 3 l. of water (Note 1), and the stirrer is started. The mixture becomes warm immediately, and within 5 minutes chloroform begins to reflux. When the reaction becomes very vigorous the stirrer is stopped and the flask is cooled with running water (Note 2). The stirring is resumed as soon as feasible and is continued for 3–4 hours, when the temperature of the mixture will have dropped to that of the room. Sodium bisulfite (about 5 g.) is then added to react with the excess hypochlorite (Note 3).
One of the condensers is then replaced by a dropping funnel, and enough 50% sulfuric acid (about 200 ml.) is added, with stirring and cooling, to make the solution acid to Congo red paper. When the solution has cooled, it is extracted with eight 400-ml. portions of ether (Note 4). The ether extract is carefully distilled on a steam bath until the ether and chloroform are removed.
The residue is then placed in a modified Claisen flask and distilled under reduced pressure. Dimethylacrylic acid distils at 100–106°/20 mm. The yield of white solid is 49–53 g. (49–53%). This product melts at 60–65°. It may be further purified by recrystallization from petroleum ether (b.p., 60–70°) or water (Note 5).
2. Notes
1. The hypochlorite is prepared according to Org. Syntheses, 17, 66; Coll. Vol. 2, 429 (1943), Note 2. It is cooled to 10° before it is placed in the flask.
2. The flask is cooled only as much as is necessary to keep the chloroform refluxing gently. After 30 minutes the reaction will have subsided enough so that no further cooling is necessary.
3. When a few milliliters of the solution no longer liberate iodine from a slightly acid potassium iodide solution, enough sodium bisulfite has been added.
4. It is important that the ether be well shaken with the solution during the extractions.
5. For recrystallization from water, 48–50 g. of the acid is dissolved in 450 ml. of hot water. The solution is cooled in ice for several hours, and the crystalline precipitate is filtered with suction and dried overnight in a desiccator. The yield of pure dimethylacrylic acid melting at 66–67.5° is 35–40 g., a recovery of 70–83%.
3. Discussion
This acid has been prepared from various α-haloisovaleric acid derivatives by elimination of the halogen together with one of the β-hydrogen atoms;1,2,3,4 from β-hydroxyisovaleric acid derivatives by elimination of water;5,6,7 by action of sodium isobutoxide on iodoform;8 by the condensation of malonic acid with acetone;9,10,11 by the reaction of acetone and ketene;12 by condensation of acetoacetic ester with acetone and action of barium hydroxide on the product, isopropylidene acetoacetic ester;13 by the action of alkali upon 2,4-dibromo-2-methyl-butanone;14 by the incomplete ozonolysis of phorone;15 by the action of alcoholic potassium hydroxide upon 2,5,5,7-tetramethylocta-2,6-diene-4-one;16 by the action of potassium hydroxide on isopropenylacetic acid;17 by the action of aluminum chloride on α,α-dimethylsuccinic anhydride;18 by metallating isobutylene with amylsodium, carbonating, and acidifying;19 by the action of hypohalites on mesityl oxide;20,21,22 and by the action of sulfuric acid on 3-methyl-3-butenoic acid.23

References and Notes
  1. Duvillier, Compt. rend., 88, 913 (1879); Ann. chim. phys., (5) 19, 428 (1880); Bull. soc. chim. France, (3) 3, 507 (1890); (3) 5, 848 (1891).
  2. Weinig, Ann., 280, 252 (1894).
  3. Perkin, J. Chem. Soc., 69, 1470 (1896).
  4. Sernow, J. Russ. Phys. Chem. Soc., 32, 804 (1900) [Chem. Zentr., 1901, I, 665].
  5. Semljanitzin and Saytzeff, Ann., 197, 72 (1879).
  6. v. Miller, Ann., 200, 261 (1880).
  7. Neubauer, Ann., 106, 63 (1858).
  8. Gorbow and Kessler, Ber., 17, Ref. 67 (1884); 20, Ref. 776 (1887).
  9. Dutt, J. Ind. Chem. Soc., 1, 297 (1924).
  10. Masset, Ber., 27, 1225 (1894).
  11. Knoevenagel, Chem. Zentr., 1905, II, 726.
  12. U. S. pat. 2,382,464 [C. A., 40, 1867 (1946)].
  13. Pauly, Ber., 30, 481 (1897).
  14. Favorski and Wanscheidt, J. prakt. Chem., (2) 88, 665 (1913).
  15. Harries and Türk, Ann., 374, 347 (1910).
  16. Deux, Compt. rend., 208, 522 (1939).
  17. Morton, Brown, Holden, Letsinger, and Magat, J. Am. Chem. Soc., 67, 2224 (1945).
  18. Desfontaines, Compt. rend., 134, 293 (1902).
  19. U. S. pat. 2,454,082 [C. A., 43, 1795 (1949)].
  20. Kohn, Montash., 24, 770 (1903).
  21. Barbier and Lesser, Bull. soc. chim. France, (3) 33, 815 (1905).
  22. Cuculescu, Bull. Fac. Stiinte Cernauti, 1, 53 (1927); [C. A., 26, 1897 (1932)].
  23. Wagner, J. Am. Chem. Soc., 71, 3214 (1949).

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

petroleum ether

isopropylidene acetoacetic ester

phorone

sulfuric acid (7664-93-9)

ether (60-29-7)

chloroform (67-66-3)

potassium iodide (7681-11-0)

sodium bisulfite (7631-90-5)

iodine (7553-56-2)

acetone (67-64-1)

aluminum chloride (3495-54-3)

potassium hydroxide (1310-58-3)

barium hydroxide (17194-00-2)

Mesityl oxide (141-79-7)

Ketene (463-51-4)

iodoform (75-47-8)

Malonic acid (141-82-2)

potassium hypochlorite

hypochlorite (14380-61-1)

dioxane (5703-46-8)

isobutylene (9003-27-4)

β,β-Dimethylacrylic acid,
Senecioic acid (541-47-9)

Dimethylacrylic acid

β-hydroxyisovaleric acid (625-08-1)

sodium isobutoxide

2,4-dibromo-2-methyl-butanone

2,5,5,7-tetramethylocta-2,6-diene-4-one

isopropenylacetic acid,
3-methyl-3-butenoic acid (53774-20-2)

α,α-dimethylsuccinic anhydride (17347-61-4)

amylsodium