Reactions of 2-Unsubstituted 1 H -Imidazole 3-Oxides with Heterocumulenes and Dimethyl Acetylenedicarboxylate

Mlostoń, Grzegorz; Gendek, Tomasz; Heimgartner, Heinz

doi:10.1016/s0040-4020(00)00449-x

Cited by 58 publications

(59 citation statements)

References 12 publications

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“…their applications as building blocks of imidazole derivatives [1][2][3] and for their diverse biological activities [4][5][6]. Convenient syntheses of 2-unsubstituted imidazole N-oxides are condensations of α-(hydroxyimino)ketones with in situ generated methylidenamines [7], of α-aminooximes with orthoformates [8], and of diimines with formaldoxime [9].…”

Section: Introduction -Imidazole N-oxides Are Interesting Compounds mentioning

confidence: 99%

“…In fact, they react with dipolarophiles, such as dimethyl acetylenedicarboxylate [2] [12], isocyanates and isothiocyanates [2], as well as with thioketones and thioketenes [7] to give ultimate products, which result from subsequent conversions of the initially formed [2+3]-cycloadducts. Of special mechanistic interest is the reaction of 1a with thioketene 2, in which the formation of two sets of products, i.e.…”

Section: Introduction -Imidazole N-oxides Are Interesting Compounds mentioning

confidence: 99%

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Reactions of 2-Unsubstituted 1H-Imidazole 3-Oxides with 2,2-Bis(trifluoromethyl)ethene-1,1-dicarbonitrile: A Stepwise 1,3-Dipolar Cycloaddition

Mlostoń

Jasiński

Linden

et al. 2006

HCA

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The reaction of 1,4,5-trisubstituted 1H-imidazole-3-oxides 1 with 2,2-bis(trifluoromethyl)ethene-1,1-dicarbonitrile (7, BTF) yielded the corresponding 1,3-dihydro-2H-imidazol-2-ones 10 and 2-(1,3-dihydro-2H-imidazol-2-ylidene)malononitriles 11, respectively, depending on the solvent used. In one example, a 1 : 1 complex, 12, of the 1H-imidazole 3-oxide and hexafluoroacetone hydrate was isolated as a second product. The formation of the products is explained by a stepwise 1,3-dipolar cycloaddition and subsequent fragmentation. The structures of 11d and 12 were established by X-ray crystallography.

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Section: Introduction -Imidazole N-oxides Are Interesting Compounds mentioning

confidence: 99%

Section: Introduction -Imidazole N-oxides Are Interesting Compounds mentioning

confidence: 99%

Reactions of 2-Unsubstituted 1H-Imidazole 3-Oxides with 2,2-Bis(trifluoromethyl)ethene-1,1-dicarbonitrile: A Stepwise 1,3-Dipolar Cycloaddition

Mlostoń

Jasiński

Linden

et al. 2006

HCA

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“…Among N-nucleophiles, imidazoles and 1,2,4-triazoles are known to intercept thiocarbonyl S-methylides [20]. In the present study, the decomposition of 15a in the presence of benzimidazole gave the 2:1 adduct 30 as the only product.…”

Section: Methodsmentioning

confidence: 44%

“…On the other hand, aliphatic derivatives of 1 show enhanced stability and extrude N 2 only at elevated temperature. In the presence of dipolarophiles, they also undergo [2+3] cycloadditions, but in the absence of trapping agents, instead of dimerization, a 1,3-dipolar electrocyclization leading to thiiranes 5 is observed [1,2].…”

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confidence: 99%

Addition of Diazomethane to Phosphonodithioformates and Reactions of Phosphonylated Thiocarbonyl S‐Methylides.

et al. 2005

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The reaction of phosphonodithioformates 14 with diazomethane at -60°C yielded 2,5-dihydro-1,3,4-thiadiazoles 15 as unstable intermediates. Their structure was evidenced by the base-catalyzed elimination of methylsulfane leading to 1,3,4-thiadiazole-2-phosphonates. At ca. -35°C, thermal decomposition of 15 by N2-elimination led to reactive thiocarbonyl S-methylides 17. In the absence of trapping reagents, these 1,3-dipoles undergo a head-to-head dimerization leading to 1,4-dithianes 18. An intermediate zwitterionic dimer 19 was detected by 31P NMR spectroscopy. The initially formed thiocarbonyl S-methylide 17 as well as an open-chain zwitterionic dimer 20 was intercepted by methanol. Stable interception products were also obtained with S-and N-nucleophiles.

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“…In a recent paper we described the reaction of diethyl diazomethanephosphonate (1) with aromatic thioketones (2). 1 The most reactive thioketones, i.e., 9H-fluorene-9-thione and thiobenzophenone, in THF reacted with 1 at temperatures below 0 °C to give 1,4-dithianes (3) and 1,3-dithiolanes (4), respectively (Scheme 1).…”

Section: Introductionmentioning

confidence: 99%

Formation of Phosphonylated Thiiranes in the Reaction of a Diazomethanephosphonate and Cycloaliphatic Thioketones.

et al. 2007

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The reaction of diethyl diazomethanephosphonate (1) with cycloaliphatic thioketones (6) in THF at room temperature leads to the corresponding thiirane-2-phosphonates (7) in good yield. A reaction mechanism via 1,3-dipolar cycloaddition of the diazo compound with the C=S group to give the 2,5-dihydro-1,3,4-thiadiazole-2-phosphonate as an intermediate, which spontaneously eliminates nitrogen is most likely. The resulting thiocarbonyl ylide undergoes a 1,3-dipolar electrocyclization to yield a thiirane. These products can be desulfurized smoothly by treatment with tris(diethylamino)phosphine to give alpha,beta-unsaturated phosphonates.

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Reactions of 2-Unsubstituted 1 H -Imidazole 3-Oxides with Heterocumulenes and Dimethyl Acetylenedicarboxylate

Cited by 58 publications

References 12 publications

Reactions of 2-Unsubstituted 1H-Imidazole 3-Oxides with 2,2-Bis(trifluoromethyl)ethene-1,1-dicarbonitrile: A Stepwise 1,3-Dipolar Cycloaddition

Reactions of 2-Unsubstituted 1H-Imidazole 3-Oxides with 2,2-Bis(trifluoromethyl)ethene-1,1-dicarbonitrile: A Stepwise 1,3-Dipolar Cycloaddition

Addition of Diazomethane to Phosphonodithioformates and Reactions of Phosphonylated Thiocarbonyl S‐Methylides.

Formation of Phosphonylated Thiiranes in the Reaction of a Diazomethanephosphonate and Cycloaliphatic Thioketones.

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