- One-Pot Synthesis of B-Ring Ortho-Hydroxylated Sappanin-Type Homoisoflavonoids
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A reliable method for the synthesis of B-ring hydroxylated homoisoflavonoids and 3-hetarylmethyl chromones has been developed. The method involves an initial oxa-Diels-Alder reaction of ortho-quinone methides generated from aryl/hetaryl-substituted ortho-(N,N-dimethylaminomethyl)phenols with (2E)-3-(N,N-dimethylamino)-1-(2-hydroxyphenyl)prop-2-en-1-ones and the subsequent cascade of reactions. This synthetic strategy avoids conventional multistep protocols and does not require the protection of hydroxyl groups, thus allowing the facile synthesis of a library of various aromatic and heterocyclic analogues of naturally occurring homoisoflavonoids.
- Mrug, Galyna P.,Myshko, Nataliia V.,Bondarenko, Svitlana P.,Sviripa, Vitaliy M.,Frasinyuk, Mykhaylo S.
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- Reaction of sarcosine with chromone-3-carbaldehyde and 6,6′- (polymethylenedioxy)di(chromone-3-carbaldehyde)
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On treatment with N-methylglycine in DMF, the chromone-3-carbaldehydes 1a-c produce 3-[3-(2-hydroxybenzoyl)-1-methyl-2,5-dihydropyrrol-2-yl]-4H-chromen-4- ones 10a-c and the deformylated products 9a-c, whereas the bischromone derivatives 12a-c give the bis[3-(2-hydroxybenzoyl)-1-methylpyrrole] structures 13a-c.
- Ghosh, Tarun,Bandyopadhyay, Chandrakanta
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p. 190 - 192
(2008/02/08)
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- Benzopyrans : Part 40 - Alumina mediated transformations of 4-oxo-4H-1- benzopyran-3-carbaldehyde, -3-carboxylic acid and their 2-methylhomologues
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In contact with alumina, the title aldehyde 1 (R = H, Me, Cl) gives the chromones 5 and 9,12 whereas the acid 2 affords the chromones 7, 10 and acetophenone 23. Alumina converts the aldehyde 3 to the xanthone 14, and the corresponding acid 4 to the chromone 8 and diketone 24.
- Ghosh, Chandra Kanta,Bhattacharyya, Samita
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p. 166 - 172
(2007/10/03)
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- Benzopyrans: Part 34 - Reactions of 3-substituted 1-benzopyran-4-ones with N-phenacylpyridinium bromide
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N-Phenacylpyridinium bromide in the presence of potassium carbonate gives the indolizine 10 and pyridinium salt 12 with the aldehyde 1 as well as the acid 2, azirine 14 with the nitrile 3, and zwitterion 16 with the ester 4. The pyridinium bromide 12 is converted into 10, and a mixture of 5 and 10 on refluxing in pyridine and dimethylformamide, respectively.
- Ghosh, Chandra Kanta,Sahana, Sirin
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p. 203 - 206
(2007/10/03)
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