- Iodoenolcyclization. III. A General Approach to Tetrasubstituted Furans from 2-Alkenyl-1,3-Dicarbonyl Compounds.
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2,3,4,5-tetrasubstituted furans were easily obtained from of 2-alkenyl-1,3-dicarbonyl compounds by an efficient three steps synthesis.
- Antonioletti, Roberto,Cecchini, Cristina,Ciani, Barbara,Magnanti, Stefano
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- Furan and Pyrrole Formation from 2-Nitro-1-phenylpropene and Acetoacetic Esters
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Methyl acetoacetate and 2-nitro-1-phenylpropene react to yield an adduct formulated as 5-methoxycarbonyl-3,6-dimethyl-4-phenyl-5,6-dihydro-4H-1,2-oxazine-2-oxide (6B).This compound is very reactive and is transformed, upon dissolution in dimethyl sulphoxide, into a mixture of methyl 2-acetyl-4-nitro-3-phenylpentanoate (6C) and methyl 2,5-dimethyl-4-phenyl-3-furoate (3a).Dissolution of (6B) in chloroform brought about its conversion into methyl 2-acetyl-4-oxo-3-phenylpentanoate (4a).Treatment of (6B) with F3B:OEt2 in ether produced the diketone (4a) and methyl 1-hydroxy- 2,5-dimethyl-4-phenylpyrrole-3-carboxylate (11); and treatment of (6B) with hydrogen chloride in ether afforded the furoic ester (3a), the diketone (4a), and the 1-hydroxypyrrole (11).The reaction of (6B) with methylamine gave methyl 4,5-dihydro-2,5-dimethyl-5-methylazo-4-phenylfuran-3-carboxylate (9) and methyl 1,2,5-trimethyl-4-phenylpyrrole-3-carboxylate (12); the former compound could be quantitatively converted into the pyrrole (12) by treatment with an excess of methylamine.
- Gomez-Sanchez, Antonio,Fernandez-Fernandez, Rosario,Pascual, Conrado,Bellanato, Juana
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p. 2701 - 2713
(2007/10/02)
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- One-Pot Synthesis of 3-Methoxycarbonyl-2,5-dimethyl-4-substituted-phenylfurans
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Reinvestigation of the reaction of 2-nitro-1-substituted-phenylpropanes (1-5) with methyl acetoacetate in presence of piperidine has furnished an improved one-pot synthesis of 3-methoxycarbonyl-2,5-dimethyl-4-substituted-phenylfurans (11-13).The intermediates of this reaction in a few cases have been isolated.
- Niwas, Shri,Kumar, Shiv,Bhaduri, A. P.
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p. 914 - 915
(2007/10/02)
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