Metal-free, Br?nsted acid-mediated synthesis of coumarin derivatives from phenols and propiolic acids
A novel synthesis of coumarin derivatives by Br?nsted acid-mediated condensation and intramolecular cyclization of phenols and propiolic acids was reported. This transformation requires the use of TfOH in place of a conventional metal mediator, and it occurs under mild conditions and provides rapid access to coumarin derivatives in good yields.
Choi, Hyuck,Kim, Jaehyun,Lee, Kooyeon
supporting information
p. 3600 - 3603
(2016/07/21)
Process for preparing coumarin derivatives using phenol and propiolic acid
Provided is a manufacturing method of coumarin derivative. The manufacturing method of coumarin derivative comprises a step of making a phenol compound react with a propiolic acid compound. According to the present invention, the manufacturing method of coumarin derivative is quick and efficient, and is useful to fields requiring synthesis of coumarin derivatives of various structures.COPYRIGHT KIPO 2016
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Paragraph 0104; 0105
(2017/01/12)
Synthesis of coumarins by Pt-catalyzed hydroarylation of propiolic acids with phenols
Synthesis of coumarins from phenols and propiolic acids was examined by using a Pt catalyst such as PtCl2/AgOTf, K2PtCl4/AgOTf, and K2PtCl4/AgOAc. Propiolic acid reacted even with less reactive phenols in trifluoroacetic acid to give coumarins and dihydrocoumarins. In the case of substituted propiolic acids, phenylpropiolic acid and 2-octynoic acid, the reactions proceeded selectively to afford coumarins in good to high yields.
Oyamada, Juzo,Kitamura, Tsugio
p. 6918 - 6925
(2007/10/03)
Further studies of orientation effects in the Pechmann synthesis of coumarins
A study of orientation effects in the Pechmann synthesis with some meta-substituted phenols is presented. Variation of the reaction conditions with malic acid indicates that whilst the proportion of 5-chlorocoumarin diminishes at higher temperatures that of 5-methoxycoumarin increases, accompanied by cleavage of the ether function under certain conditions. Reactions with ethyl acetoacetate give only the 4,7-isomers. Peri-substituent effects in 1 H and 13C NMR spectroscopy have been used for product identification.
Osborne, Alan G.,Andrews, Steven J.,Mower, Rachel
p. 319 - 338
(2007/10/03)
Enolethers, XVIII. - A Simple Synthesis of Coumarins
In boiling 1,2-dichloroethane 3-ethoxyacryloyl chloride (1) reacts with phenols 2 to yield 3-ethoxyacrylates 3, which by treatment with conc. sulfuric acid/10percent SO3 cyclize to give coumarins 9 in good yields.The methoxy-substituted compounds 3d and 3k do not react to coumarins 9 with H2SO4/SO3 but with POCl3/H2O at room temperature.
Ziegler, Thomas,Moehler, Hans,Effenberger, Franz
p. 373 - 378
(2007/10/02)
ORIENTATION EFFECTS IN THE PECHMANN REACTION SYNTHESIS OF 5,6-DIMETHYLCOUMARIN AND AN EXAMINATION OF ORTHO-PROXIMITY EFFECTS IN 13C NMR SPECTROSCOPY
In the Pechmann reaction with malic acid, m-cresol and 3,4-xylenol give mixtures of alkylcoumarins containing about 10percent of the 5- and 5,6-isomers respectively. 7-Alkylcoumarins only are obtained from the reaction with ethylacetoacetate.A study of ortho-proximity effects on the 13C NMR of dimethylcoumarins is reported, and the results have been correlated with similar effects in other aromatic and heteroaromatic systems.
Osborne, A. G.
p. 2021 - 2025
(2007/10/02)
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