- A Mukaiyama-Claisen Approach to 3,5-Diketo Esters
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A thermally promoted synthesis of 3,5-diketo esters via a Mukaiyama-Claisen reaction of 4H-1,3-dioxin-4-one derivatives with silyl enolates has been developed. The desired oligocarbonyl compounds were obtained with moderate to good yields.
- Wang, Qinggang,List, Benjamin
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- 4-cyano-7, 8-dihydroisoquinoline derivative as well as preparation method and application thereof
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The invention relates to the technical field of organic synthesis, in particular to a 4-cyano-7, 8-dihydroisoquinoline derivative as well as a preparation method and application thereof. According to the invention, symmetric and asymmetric dicyanomethylene-4H-pyran derivatives and secondary amine are used as raw materials, and a series of 4-cyano-7, 8-dihydroisoquinoline derivatives are prepared through ring opening and continuous ring closing reactions; and the reaction has the advantages of easily available raw materials, mild reaction conditions, wide substrate range, high yield and the like, is simple to operate, and avoids the defects of tedious steps, harsh reaction conditions, use of toxic and expensive metal catalysts and the like in conventional isoquinoline compound construction. The preparation method provides new possibilities for design and synthesis of isoquinoline molecules and application of the isoquinoline molecules in solid-state fluorescent materials.
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Paragraph 0067
(2021/05/05)
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- Asymmetrical 4H-pyran derivatives and preparation method and application thereof
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The invention relates to asymmetrical 4H-pyran derivatives and a preparation method and application thereof. The asymmetrical 4H-pyran derivatives comprise three structures: 6a, 6b and 6c. The preparation method of the asymmetrical 4H-pyran derivative com
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Paragraph 0038; 0039; 0043-0047; 0051-0053
(2019/01/23)
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- Synthesis of new efficient laser dyes of red spectral range, the DCM analogs, based on 2-aryl-6-methyl-4H-pyrone
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A new method was developed for the synthesis of 2-aryl-6-methyl-4H-pyrones by the condensation of arylmethylketones with the acetoacetic ester ethylene ketal in the presence of sodium alkoxylate. New laser merocyanine dyes, the analogues of 4-dicyanomethylene-2-methyl-6-[(4-dimethylamino)styryl]-4H-pyran (DCM), were obtained based on the synthesized 2-aryl-4-pyrones. The dyes are characterized by high generation efficiency in the red spectral range.
- Ponomareva,Lugovskii,Lugovskii,Males,Komlev,Nifant'Ev
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p. 2310 - 2315
(2012/03/12)
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- Synthesis of pyran-4-ones from isoxazoles
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A synthesis of mono-, di- and tri-substituted pyran-4-ones from isoxazoles is reported. The isoxazoles can be synthesized from readily available starting materials and undergo a reductive cleavage reaction with Mo(CO)6 to generate enamino keton
- Li, Chun-Sing,Lacasse, Edith
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p. 3565 - 3568
(2007/10/03)
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- A convenient synthesis of di- and trisubstituted γ-pyrones
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Treatment of ketodiynes or allenynones with hot aqueous acid results in the facile formation of di- or tri-substituted γ-pyrrones. The mechanism of this new process was established.
- Majetich,Zhang,Dreyer
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p. 449 - 452
(2007/10/02)
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- Reactions of Dianions of Acyclic β-Enamino Ketones with Electrophiles. Part 5. Esters: Synthesis of Pyridin-4-one and Pyran-4-one Derivatives
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The electrophilic attack of esters to dianions of β-monosubstituted amino-α,β-unsaturated ketones and the subsequent cyclisation of the addition product offers a valuable generalisation of the synthesis of N-substituted pyridin-4-ones and pyran-4-ones.The reaction proceeds in good to high yields with α'-dianions.A side metallation reaction is observed with aliphatic esters.Product distribution is influenced by the nucleophilic ability of nitrogen and the electrophilicity of the carbonyl group which are involved in cyclisation.The reaction of γ-dianions with esters is the first example of a reactivity of these systems which resembles alkyl organometallic reagents more than enolates.In fact the major product of this reaction is the alcohol with incorporation of two enaminone moieties.
- Bartoli, Giuseppe,Bosco, Marcella,Cimarelli, Cristina,Dalpozzo, Renato,Guercio, Giuseppe,Palmieri, Gianni
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p. 2081 - 2086
(2007/10/02)
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- Pyran Annelation: An Effective Route to a Tricyclic Dienone
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A new pyran annelation reaction was investigated. 2,6-Dimethyl-4H-pyran-4-one (2) was converted to 2((p-tolylsulfonyl)methyl)-6-methyl-4H-pyran-4-one (7) which was alkylated at the C-2 methylene position regioselectively, and the p-tolylsulfonyl group can be easily eliminated with an aluminium amalgam reduction.On the other hand the pyran-4-one ring was easily transformed into an 1,5-diketone derivative.By joining and applying these selective alkylations and transformations, tricyclic dienone 22 was effectively synthesized from 2.
- Yamamoto, Makoto,Iwasa, Seiji,Takatsuka, Kenichi,Yamada, Kazutoshi
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p. 346 - 349
(2007/10/02)
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- Reaction of Diketene-Acetone Adduct with Enamines, Ketene Acetals, Vinyl Ethers, and β-Diketones
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Diketene-acetone adduct (1) generates acetylketene (2) under heating.In order to compare the reactivity of 2 with that of diketene, the reaction of 1 with electron-rich olefins was investigated.On heating with 1 primary enamines (3a-d) produced the corresponding 3-substituted 2,6-dimethyl-4(1H)-pyridones (4a-d), while the tertiary enamine 3e gave the 4-pyrone derivative (7).The reaction of 1 with ketene acetals (8) gave the 2,2-diethoxy-2,3-dihydro-4-pyrone derivatives (9).The vinyl ether derivatives 13 similarly reacted with 1 to give the 4-pyrone derivative 15 or 16 as the major product.The result shows that both diketene and 2 react with electron-rich olefins in a similar manner.Keywords -- diketene; acetylketene; diketene-acetone adduct; enamine; ketene acetal; vinyl ether; 1,3-dioxin-4-one; 4-pyridone; 4-pyrone; cycloaddition
- Sato, Masayuki,Ogasawara, Hiromischi,Kato, Keiko,Sakai, Masako,Kato, Tetsuzo
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p. 4300 - 4305
(2007/10/02)
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