- Synthesis of heterocyclic compounds using basic zeolite Csβ
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The application of the basic zeolite Csβ as catalyst for the interaction of methyl vinyl ketone (MVK) with 5-methoxybenzimidazole-2-thiol leads to a Michael heteroreaction exclusively at the N-nucleophilic center with the formation of a fairly unusual product of di-addition of MVK to thiol. The reaction of 1,2,4-triazole-3-thiol with MVK in the presence of zeolite Csβ proceeds both at the S- and also at the N-nucleophilic center and leads to the formation of products of mono- and diaddition according to Michael, and also to the product of heterocyclization. On interacting crotonaldehyde with salicylaldehyde in the presence of Csβ 2-methyl-2H-chromene-3-carbaldehyde is formed.
- Suslov,Korchagina,Volcho,Salakhutdinov
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- Recrossing and dynamic matching effects on selectivity in a diels-alder reaction
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Up and down the hill: The products from the hetero-Diels-Alder reaction of acrolein with methyl vinyl ketone arise from a single transition state (see scheme) and trajectory studies accurately predict the selectivity. In an extension of the dynamic matchi
- Wang, Zhihong,Hirschi, Jennifer S.,Singleton, Daniel A.
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supporting information; experimental part
p. 9156 - 9159
(2010/03/03)
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- Promotion of one-pot Robinson annelation achieved by gradual pressure and temperature manipulation under supercritical conditions
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The one-pot Robinson annelation from 2-methyl-cyclohexane-1,3-dione with 3-buten-2-one can be achieved in high yield (95%) and high selectivity (95%) by pressure and temperature manipulation using supercritical carbon dioxide in the presence of MgO catalyst, whose method could be applied for various ketones to synthesize fused polycyclic compounds.
- Kawanami, Hajime,Ikushima, Yutaka
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p. 5147 - 5150
(2007/10/03)
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- Study on the functionalization and reactivity of bicyclic acetal compounds
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Bicyclic acetal was known as a versatile reagent for the structural transformation reactions. Bicyclic acetal was functionalized to the acetal-lactol and halo-lactol, and applied for the new rearrangement reactions. The structural identification and rearrangement mechanism were discussed herein.
- Jun, Jong-Gab,Kim, Ae-Ran,Sung, Hoon Kim
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- Facile syntheses of 7,7-dimethyl-6,8-dioxabicyclo [3.2.1]octane, a constituent of the Japanese hop oil, and frontalin via hetero Diels-Alder reaction using dilution method
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A constituent of the Japanese hop oil, Humulus lupulus, and frontalin has been prepared as racemates in short and the most convenient pathway via hetero Diels-Alder reaction using dilution method.
- Jun, Jong-Gab,Lee, In-Suk
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p. 1159 - 1165
(2007/10/03)
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- Novel dienes and dienophiles, VI: On the chemical behavior of Z-ethynyl-1,3-butadiene
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The behavior of 2-ethynyl-1,3-butadiene (1) as the diene component in Diels-Alder additions has been studied using a selection of representative double and triple bond dienophiles. The latter include maleic anhydride (5a), diethyl fumarate (6), benzoquinone (7), methyl acrylate (11), juglone (20), 1-methylcyclopropene (23), dimethyl acetylenedicarboxylate (26), propiolic aldehyde (32), 4-phenyl-1,2,4-triazolin-3,5-dione (35) and diethyl azodicarboxylate (37). [2 + 4] Cycloadducts were formed in all cases in varying yields. The addition is accompanied by thermal dimerization of 1 which leads to 1,4-diethynyl-4-vinyl-1-cyclohexene (43) and 1,6-diethynyl-1,5-cyclooctadiene (39). The mechanism of this dimerization is discussed. In a competition experiment towards maleic anhydride (5a), diene 1 was shown to be ca. five times less reactive than isoprene. VCH Verlagsgesellschaft mbH, 1996.
- Hopf, Henning,Jaeger, Helge,Ernst, Ludger
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p. 815 - 824
(2007/10/03)
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- STRUCTURE - ODOR CORRELATION - IX: FROM 1,8-CINEOL TO SESQUICINEOL - CHANGE OF ODOR WITH STRUCTURE
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Cu(I) catalyzed 1,4-Grignard reaction of the key compound 6 led to the bicyclic keto ethers 7-15 together with small amounts of the alcohols 16-25.Wolff-Kishner reduction of 8-15 gave the 1,8-cineol homologues 26-32 and sesquicineol (2). - The fresh and camphoraceous odor of 1 changes stepwise with increasing side chain to herbaceous and spicy notes, compounds with branched side chains show lavender undertones. 2 has a pleasant fruity, floral and sweet fragrance.
- Weyerstahl, Peter,Krohn, Kerstin
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p. 3503 - 3514
(2007/10/02)
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- Preparation and Diels-Alder Reactivity of Several New Chalcogen-Halogen Substituted Butadienes
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Addition of halogens and pseudohalogens across one ?-bond of 1,4-dichlorobut-2-yne, followed by a 1,4-elimination, is an efficient synthesis of several new polysubstituted butadienes.If the product dienes have a sulfur or selenium substituent they are quite reactive, undergoing cycloaddition with the moderately reactive dienophile methyl vinyl ketone at 20 deg C in the presence of boron trifluoride etherate.The regiochemistry of the cycloadditions was elucidated, and the limitations of the methodology are discussed.
- Bridges, Alexander J.,Fischer, John W.
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p. 2954 - 2961
(2007/10/02)
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- 3-Phenylmethoxytetrahydropyran herbicides
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Certain 3-phenylmethoxytetrahydropyrans, useful as herbicides.
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- Reactions of 3-(Phenylthio)-3-buten-2-one with Cycloalkanones. A New Approach to Fused Phenols
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Synthesis and properties of 3-(phenylthio)-3-buten-2-one (7) have been described.The butenone 7 reacted with lithium cycloalkanone enolates to give ketols 14 or diketones 15 in good yields, which were easily transformed into fused phenols 17 by the treatment with p-toluenesulfonic acid or sodium ethoxide, respectively.Oxidative elimination of the sulfenyl group of 14a afforded also 2-naphthol 17a.Tetrahydronaphthalene 23, a key intermediate of calamenene 1a and calamenenal 1b, was successfully synthesized by this approach by starting from l-carvone (19).Bicyclooctanone 25 was obtained in the reaction of 7 with kinetic enolate of 2-cyclohexen-1-one in 84percent yield.
- Takaki, Ken,Okada, Michikazu,Yamada, Michio,Negoro, Kenji
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p. 1200 - 1205
(2007/10/02)
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