I tried to synthesis the aforementioned compound by reacting 2,4-dihydroxybenzaldehyde and ethyl acetoacetate in the present of piperidine as catalyst. According to the method that I'm using, after being left overnight, yellow solid should be forming. However I did not obtained any solid the next day. Can somebody share another method to synthesis this compound?
Thank you in advance.
I hope following may work for you.
link.springer.com/content/pdf/10.1631%2Fjzus.B0820079.pdf
www.mdpi.com/1420-3049/17/9/10846/pdf
www.sciencedirect.com/science/article/pii/S1878535214000732
The knoevenagel condensation you are using is one of the best ways of obtaining your product. Just because you haven't observed a solid yet, it doesn't mean the reaction hasn't worked. The transesterification may not have gone to completion; try heating it up and cooling down again.
Repeat the reaction, use toluene or benzene as a solvent at reflux and a dean stark apparatus to drive off water and ethanol formed in the reaction. Monitor by TLC.
I totally agree with Dr. Eric Harris comments
and
See also some old but valid literature
The Fluorescence of Some Coumarins1
Charles E. Wheelock
J. Am. Chem. Soc., 1959, 81 (6), pp 1348–1352
DOI: 10.1021/ja01515a021
Improved synthesis of some hydroxycoumarins
M. Bulut, Ç. Erk
Dyes and Pigments, Volume 30, Issue 2, 1996, Pages 99–104
Follow the methods explained in the attachment but start by
2,4-dihydroxybenzaldehyde, after the first step of condensation,
undergo acetylation with acetic anhydride or acetyl chloride.
Undergo the cyclization reaction and hydrolyze the acetyl protecting ester.
Good luck
synthesize 3-acetyl-7-hydroxycoumarin
React 2,4-dihydroxy benzaldehyde with acetoacetic ester & the cyclize with out isolation of the intermediate product with PPA or Conc. sulphuric acid , neutralize the reaction mix. with Na2CO3 & keep for 24 hrs., white solid separates out .
Dear Dal N. l
You can follow the following paper.
www.mdpi.com/1420-3049/17/9/10846/pdf
Good Luck
Prof. Dr. Talaat El-Emary
Do the reaction in Methanol as a solvent and 2 drops of piperidine as a catalyst. U will get it. I followed the same procedure and got the product in good yields.
2,4-dihydroxybenzaldehyde and ethyl acetoacetate in the presence of conc. H2SO4 in 00C.
Follow the procedure from this paper:
Org. Biomol. Chem, 2011, 9, 6943-6948
check this paper
Journal of Medicinal Chemistry, 2011, Vol. 54, No. 1
@ Dal N. L. Please provide ur e-mail ID i will forward it to you.
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