- Stereoselective synthesis of Heliannuol G
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The first stereoselective synthesis of Heliannuol G has been achieved employing an o-quinone methide intermediate. The present synthesis triumphs over all the drawbacks associated with the reported one and reveals an impressive overall yield of 12.37%.
- Sarkar, Debayan,Ghosh, Manoj Kumar
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p. 4336 - 4339
(2017/10/18)
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- Structural study of three o-hydroxyacetophenone derivatives using X-ray powder diffraction: Interplay of weak intermolecular interactions
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A family of three o-hydroxyacetophenone derivatives, 2-hydroxy-5-methoxy-4- methylacetophenone (1), 5-methoxy-4-methyl-2-(phenylmethoxy)acetophenone (2) and 2-O-(α-methyl carboethoxy)-5-methoxy-4-methyl-acetophenone (3) were synthesized and their crystal structures were solved using laboratory X-ray powder diffraction data along with a detailed analysis of the Hirshfeld surfaces and 2D-fingerprint plots, facilitating a comparison of intermolecular interactions. The DFT optimized molecular geometries in 1 and 3 agree closely with those obtained from the crystallographic studies. In 2, however, the relative orientation of the two planar phenyl rings as established by the X-ray analysis and quantum mechanical calculations differs by 34.9°. The crystal packing in the compounds is stabilized by an interplay of weak hydrogen bonds, such as C-H...O, C-H...π and π...π interactions, forming supramolecular assemblies. The intermolecular C-H...O hydrogen bonds in 1-3 generate C11(6) chains and Rmn(X) rings, which are further connected through C-H...π hydrogen bonds and π...π interactions to produce parallel molecular sheets built by fused R22(24) rings in 1, a three-dimensional architecture with C22(16)[R22(6)][R22(14)] synthons in 2, and a two-dimensional columnar framework in 3.
- Chattopadhyay, Basab,Ghosh, Soumen,Mondal, Swastik,Mukherjee, Monika,Mukherjee, Alok K.
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experimental part
p. 837 - 846
(2012/04/10)
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- Synthesis of coruscanones A and B, metabolites of piper coruscans, and related compounds
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Base-catalyzed rearrangements of both individual 4-(acylmethylidene) butenolides and their mixtures prepared by condensation of citraconic anhydride with various phosphoranes occur successfully only in the presence of 5.2% MeONa in MeOH (molar ratio MeONa
- Shestak,Novikov
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experimental part
p. 81 - 90
(2011/01/10)
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- A facile demethylation of ortho substituted aryl methyl ethers promoted by AlCl3
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An efficient and practical demethylation of ortho substituted aryl methyl ethers using AlCl3 has been developed. This method gives a high conversion, is simple to operate and is cost-effective. A mechanism involving the complexation of AlCl3 with the OMe and the adjacent electron withdrawing group is proposed. Many functional groups can be tolerated in the demethylation process, and 29 examples gave a demethylated product in a yield of 90-98%.
- Du, Zhen-Ting,Lu, Jing,Yu, Hong-Rui,Xu, Yan,Li, An-Pai
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experimental part
p. 222 - 227
(2010/08/04)
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- Synthesis of O-methyl epi-heliannuol E
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A synthesis of the methyl ether of an epimer of the alleochemical heliannuol E is described. The route involves indium mediated allylation of a benzopyranone carboxylate and subsequent one carbon degradation to a vinyl group.
- Sabui, Subir Kumar,Venkateswaran, Ramanathapuram V.
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p. 8375 - 8381
(2007/10/03)
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