Process for the preparation of cinnamic esters

Details Process for the preparation of cinnamic esters Process for the preparation of cinnamic esters

2001-12-07

2003-03-25

Richter, Johann (Department: 1621)

Organic compounds -- part of the class 532-570 series

Organic compounds

Carboxylic acid esters

C562S495000

Reexamination Certificate

active

06538154

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to a process for the synthesis of cinnamic esters and substituted cinnamic esters by condensation of aldehyde(s) with carboxylic anhydride(s) catalysed by iron(III) salts.
BACKGROUND OF THE INVENTION
The direct route to cinnamic esters is possible via the condensation of aromatic aldehydes with acetic esters (Claisen-Schmidt reaction; (Ber. 23, 976 (1890)) and can be carried out in the presence of metallic sodium. Ullmanns Encyclopedia of Industrial Chemistry 6
th
Edition, Electronic Release, 1999, Vol. A 24, 231-239 and DE 3422412 describe the condensation of benzaldehyde with acetic esters with alkoxide catalyst in alcohol.
In said cases, the catalyst is used in an at least equimolar amount relative to the benzaldehyde and thus significantly increases the preparation costs of the cinnamic ester. Handling of the catalyst is associated with a high hazard potential.
The Perkin reaction (Perkin, J. Chem. Soc. 31,388 (1877)) likewise offers the possibility of preparing cinnamic acid and cinnamic esters by reacting an aromatic aldehyde, such as benzaldehyde, and acetic anhydride with sodium acetate catalysis. Houben Weyl, Methoden der organischen Chemie [Methods of organic chemistry], 4th Ed., Vol. VIII/3, p. 443, Georg Thieme Verlag Stuttgart, 1952 describes the reaction of benzaldehyde with acetic anhydride and sodium acetate in a molar ratio of 1:1.56:0.65 under reflux/16 h. Work-up from water gives cinnamic acid in a yield of 57%.
By heating for 24 hours or by adding pyridine, it is possible to increase the yield to 70-75%.
JP A 76/15,026; CA 1976, 85:14285h describe the reaction of benzaldehyde with acetic anhydride and sodium acetate in a molar ratio of 1:0.5:0.5 and a reaction temperature of 160° C./1 h. The yield of cinnamic acid is 30% under these conditions. If sodium acetate is replaced with potassium phosphate or sodium phosphate, the yield increases to 46%.
J. R. Johnson, Org. Reactions I. 210 (1942) describes the reaction of 0.2 mol of benzaldehyde and 0.3 mol of acetic anhydride using 0.12 mol of potassium acetate. The mixture is refluxed for 5 hours at 170° C. The reaction mixture is poured onto 1,200 ml of water. Unreacted benzaldehyde is isolated by steam distillation. Activated carbon is added and the mixture is heated. Following filtration, 12-14 ml of conc. hydrochloric acid are added at elevated temperature, and the system is cooled. The precipitated crystals are filtered off with suction and dried. 16-18 g of cinnamic acid are obtained; the yield is 55-60% based on the amount of benzaldehyde used.
P. Kalnin, Helv. Chim. Acta 11, 977 (1928) describes various salts as catalysts. 1 mol of benzaldehyde and 1.5 mol of acetic anhydride are refluxed at 180° C. for 8 hours with 0.65 mol of catalyst. The yields of cinnamic acid are, following work-up, for potassium acetate 72%, for potassium carbonate 59%, for sodium carbonate 40%, for sodium acetate 39%, for sodium phosphate 36%, for potassium phosphate 20% and for potassium sulphide 32%. As well as potassium and sodium salts, amines are also possible as catalysts. For 0.33 mol of triethylamine, the yield is 19%.
A disadvantage of said process variants is the large amount of catalyst used, which makes the product expensive and hinders the reaction and also the work-up.
SUMMARY OF THE INVENTION
Therefore, an object of the present invention is to find a low-cost catalyst which, in small amounts, permits the preparation of cinnamic esters or cinnamic acid by condensation of aldehyde(s) with carboxylic anhydride(s) in the presence of a catalyst.
A process for the preparation of cinnamic esters and/or cinnamic acid by condensation of aldehydes with carboxylic anhydrides in the presence of a catalyst has been found, which is characterized in that catalysts, or catalyst mixtures, containing iron(III) salts are used.


REFERENCES:
patent: 4609756 (1986-09-01), Dorlars et al.
patent: 4618698 (1986-10-01), Beitzke
Kalnin Zur Theorie der Perkin'schen Synthese. Uber den Mechanismus der Reaction, 1928, Helvetica Chimica Acta, 11, pp. 977-1003.*
Weber, Prebiotic Sugar Synthesis: Hexose and Hydroxy Acid Synthesis from Glyceraldehyde Catalyzed by Iron(III) Hydroxide Oxide, 1992, Journal of Molecular Evolution, 35(1), pp. 1-6. Abstract Only.*
Solomons, Organic Chemistry, 5th edition, 1992, John Wiley & Sons, Inc., New York, pp. 777-778.*
Chem. Abstract, 1976 85:14285h & JP 51015026.
Chem. Abstract, 95:95470 & JP 56026197.
Houben-Weyl, Methoden der organische chemie, vol. III/3, (month unavailable) 1952, p. 443, “Herstellung von Carbonsäuren durch Kohlenstoffverkettung”.
J. Chem. Soc., 31, (month unavailable) 1877, pp. 388-427, W. H. Perkin, “On the Formation Of Coumarin and of Cinnamic and of other Analogous Acids from the Aromatic Aldehydes”.
Ullmann's Encyclopedia of Industrial Chemistry, 6thedition electronic release, 1999, vol. A 24, Cinnamic Acid—Production, Dorothea Garbe.
Helv. Chim. Acta. 11, (month unavailable) 1928, pp. 977-1003, Paul Kalnin, “Zur Theorie der Perkin'schen Synthese Über den Mechanismus der Reaktion”.
Org. Reactions I, (month unavailable) 1942, pp. 210-265, John R. Johnson, “The Perkin Reaction & Related Reactions”.
Claisen-Schmidt Reaction; (Ber. 23,) (month unavailable) 1890, pp. 976-978, L. Claisen, “Zur Darstellung der Zimmtsäure und ihrer Homologen”.

Affiliated with

Also associated with

Rating

Process for the preparation of cinnamic esters does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Process for the preparation of cinnamic esters, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for the preparation of cinnamic esters will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3036799