Mild and environmentally benign methods for the syntheses of flavanones are described. The reaction of o-hydroxyacetophenones (1) and benzaldehydes (2) in water in the presence of DABCO at room temperature gave 3-hydroxy-1-(2- hydroxylphenyl)-3-arylpropan-1-ones (3a-i) as intermediates. Followed by an intramolecular dehydration of the 3a-i with the modified Mitsunobu's reaction, the target flavanones (4a-i) were obtained. Moreover, the reaction of 1 and 2 at the same conditions but at reflux gave flavanones in one pot with good yields.
Chen, Po-Yuan,Wang, Tzu-Pin,Chiang, Michael Y.,Huang, Keng-Shian,Tzeng, Cherng-Chyi,Chen, Yi-Long,Wang, Eng-Chi
experimental part
p. 4155 - 4160
(2011/06/26)
Isolation and crystal structure of 3-aryl-1-(2-hydroxyphenyl)-3-hydroxy-1- propanones derived from Claisen-Schmidt condensation of 2-hydroxyacetophenone with benzaldehyde derivatives
2-Hydroxyacetophenone reacted with benzaldehyde derivatives under alkalinic conditions followed by addition of dilute hydrochloric acid solution to afford mixtures of the known 2-hydroxychalcone derivatives and the corresponding previously undescribed 3-aryl-1-(2-hydroxyphenyl)-3-hydroxy-1-propanones. The isolation of the β-hydroxyketone derivatives depends on the work-up conditions. Their structures were established using a combination of NMR, IR and mass spectroscopic techniques. The conformation of the β-hydroxyketones was probed using 1H NMR spectroscopy and X-ray crystallography.
Mphahlele, Malose J.,Fernandes, Manuel A.
p. 97 - 110
(2007/10/03)
Synthesis and preliminary biological evaluation of 4,6-disubstituted 3-cyanopyridin-2(1H)-ones, a new class of calcium entry blockers
The preparation of 3-cyano-4,6-diaryl-pyridin-2(1H)-ones 4a-h, calcium entry blockers related to diltiazem, is described starting from 1,3-diaryl-2-propen-1-ones 5. On preliminary pharmacological tests all compounds are active and some of them show calcium antagonistic activity superior or comparable to diltiazem. (C) 2000 Elsevier Science Ltd. All rights reserved.
Use of Nitrile Oxides in Synthesis. A Novel Synthesis of Chalcones, Flavanones, Flavones and Isoflavones
Novel methodology is developed for a three-step synthesis of chalcones, flavanones, flavones and isoflavones. 1.Salicylaldoxime is chlorinated to the corresponding hydroxamoyl chloride in the presence of pyridine, and cycloadded to styrene and phenylacetylene. 2.The isoxazole derivatives formed are reductively cleaved over Raney-Ni to β-hydroxyketones or 1,3 diketones. 3.Acid-catalyzed cyclization gives the flavonoids.Use of ω-methoxy- or ω-dialkylamino-substituted styrenes (enamines) leads regioselectively to 4-aryl-substituted isoxazoles and derived isoflavones.
Thomsen, Ib,Torssell, Kurt B. G.
p. 303 - 308
(2007/10/02)
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