- Selective synthesis of 3,4-dihydrocoumarins and chalcones from substituted aryl cinnamic esters
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Coumarins are ubiquitous in plant kingdom and have been used as antitumor, antifungals, anticoagulants, insecticides. Chalcones are also widespread in plant kingdom and have been known to possess diverse biological activities; antibacterial, antifungal, antitumor and anti-inflammatory, etc. As they are considered as important natural products, numerous synthetic approaches have been reported up to the present. We devise a new selective method of preparing dihydrocoumarins and chalcones from aryl cinnamates by the selection of reagents. Dihydrocoumarin derivatives were prepared selectively by using intramolecular cyclization catalyzed by p-toluene sulfonic acid. Also, chalcones were prepared by Fries-rearrangement catalyzed by TiCl4. This method can be used for preparing various coumarin & chalcone compounds.
- Jeon, Jae-Ho,Yang, Deok-Mo,Jun, Jong-Gab
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- The reactions of phenols with α,β-unsaturated aromatic acids in presence of polyphosphoric acid: Synthetic and mechanistic studies
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The reactions of cinnamic acid with phenol itself, catechol, hydroquinone, pyrogallol and 2-naphthol in presence PPA were studied and that with resorcinol was reinvestigated. With phenol itself and hydroquinone were obtained 3,4-dihydro-4-phenylcoumarin (1r) and 6-hydroxy-3,4-dihydro-4-phenylcoumarin (1s), respectively, as the sole products. Catechol and pyrogallol, on the other hand, afforded, besides the corresponding 3,4-dihydrocoumarins, viz. 8-hydroxy-3,4-dihydro-4-phenylcoumarin (1t) and 7,8-dihydroxy-3,4-dihydro-4-phenylcoumarin (1u), as the major products, 5,6-dihydroxy-3-phenylindanone (5b) and the chalcone 1-(2′,3′,4′-trihydroxy)-3-phenylpropan-2-en-1-one (3d), respectively, as minor products. But contrary to earlier observation, resorcinol was found to give 7-hydroxy-3,4-dihydro-4-phenylcoumarin (1v) instead of 7-hydroxyflavanone (4e). 2-Naphthol, on the other hand, afforded the chalcone derivative 1-|2′-hydroxynaphthyl|-3-phenylpropan-2-ene-1-one (7) as the exclusive product. The yields of the major products in the above reactions were 50-67% except that with phenol itself yielding 1r in 40% yield. The structures of all the products 1r, 1s, 1t, 1u, 1v, 3d, 5b and 7 were established from their various spectral (IR, 1H and 13C NMR and mass) data. Evidence for plausible mechanisms of formation of the above products was provided.
- Majumder,Chatterjee,Mukhoti
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p. 743 - 755
(2007/10/03)
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- 3,3-DIPHENYLPROPYLAMINES AND PHARMACEUTICAL COMPOSITIONS THEREOF
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Novel 3,3-diphenylpropylamines of formula (I) wherein R1 signifies hydrogen or methyl, R2, R3 and R4 independently signify hydrogen, methyl, methoxy, hydroxy, carbamoyl, sulphanoyl or halogen, and X represents a tertiary amino group -NR5, R6, wherein R5 and R6 signify non-aromatic hydrocarbyl groups, which may be the same or different and which together contain at least three carbon atoms, and which may form a ring together with the amine nitrogen, their salts with physiologically acceptable acids and, when the compounds can be in the form of optical isomers, the racemic mixture and the individual enantiomers, their use as drugs, especially as anticholinergic agents, their use for preparing an anticholinergic drug, pharmaceutical compositions containing the novel amines, and methods for preparing the same
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