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1.
The reaction of β-dicarbonyl compounds (β-ketoesters and β-diketones) with 0.34 mol equiv of trichloro- and tribromoisocyanuric acids produced regioselectively the corresponding α-monohalo β-dicarbonyl compound. On the other hand, utilization of 0.68 mol equiv of the trihaloisocyanuric acid produced the α,α-dihalo β-dicarbonyl compound. 相似文献
2.
Efficient syntheses of 2-aminopyrroles are presented starting from β-dicarbonyl compounds, bromoacetonitrile, and amines. Alkylation of β-dicarbonyl compounds with bromoacetonitrile furnished α-cyanomethyl-β-dicarbonyl compounds. The condensation reaction of α-cyanomethyl-β-dicarbonyl compounds with amines catalyzed by p-TsOH affords the corresponding enamines in good yields. Base catalyzed cyclization via the addition of an amine moiety to the carbon-nitrogen triple bond of nitrile furnished 2-aminopyrroles in high yields. 相似文献
3.
Zeghada S Bentabed-Ababsa G Derdour A Abdelmounim S Domingo LR Sáez JA Roisnel T Nassar E Mongin F 《Organic & biomolecular chemistry》2011,9(11):4295-4305
Reactions were performed from aryl azides on the one hand, and activated alkenes coming from β-dicarbonyl compounds or malonodinitrile on the other hand, either with recourse to conventional heating or to microwave activation, to afford 1-aryl-1H-1,2,3-triazoles. The mechanism and the regioselectivity of the reactions involving β-dicarbonyl compounds have been theoretically studied using DFT methods at the B3LYP/6-31G* level: they are domino processes comprising a tautomeric equilibrium of the β-dicarbonyl compounds with their enol forms, a 1,3-dipolar cycloaddition of the enol forms with the aryl azides (high activation energy), and a dehydration process (lower activation energy). The effect of non-conventional activation methods on the degradation of 1,2,3-triazolines was next studied experimentally. Finally, some of the 1,2,3-triazoles such synthesized were evaluated for their bactericidal and cytotoxic activities. 相似文献
4.
A study of the copper-catalysed direct arylation of β-dicarbonyl compounds with 2-bromobenzoic acids
The Cu-catalysed condensations of 2-bromobenzoic acids with β-dicarbonyl anions to give α-arylated-β-dicarbonyl compounds have been investigated in detail. Previously recommended experimental conditions for these reactions are shown to be in appropriate and the limited synthetic utility of these processes in the past is explained. Much superior conditions have now been developed by use of which a variety of β-dicarbonyl compounds can readily be arylated in good to excellent yield with A wide range of substituted 2-bromobenzoic acids and with certain other halo-aromatic acids. The scope and limitations of the synthetic method have been established, and a simple, high yield procedure for the preparation of homophthalic acids is described. It is shown that Cu(I) is almost certainly the effective catalyst, and information has been obtained on the probable mechanism of the substitution reaction by examination of steric and electronic effects in the halo-aromatic acids and by consideration of the structure and role of the β-dicarbonyl component. 相似文献
5.
Francis Dayer Huu Lê Dao Hellmut Gold Heike Rod-Gowal Hans Dahn 《Helvetica chimica acta》1974,57(7):2201-2209
The synthesis of 22 substituted tricarbonyl compounds is reported. They were obtained either by oxidation of β-dicarbonyl compounds with SeO2 or nitrous oxides or by oxidation of the α-bromo-β-dicarbonyl compounds with DMSO. The procedures using SeO2 or DMSO are more rapid and give in general better yields than other methods described in the literature. 相似文献
6.
Arylation of β-dicarbonyl compounds is carried out by photostimulated SRN1 reaction between bromo-benzonitriles or bromocyanopyridine and β-dicarbonyl derived monoanions. 相似文献
7.
Oxidative free radical reactions of enamino esters are described. Electrophilic carbon-centered radicals produced by the cerium(IV) ammonium nitrate (CAN) oxidation of β-dicarbonyl compounds undergo efficient addition to the C-C double bond of enamino esters. This CAN mediated free radical reaction between enamino esters and β-dicarbonyl compounds provides a novel method for the synthesis of highly substituted pyrroles. The direct CAN oxidation of β-enaminocinnamates gave the dimerization products effectively. 相似文献
8.
Dennis Liotta Manohar Saindane Christopher Barnum Harry Ensley Pattabiraman Balakrishnan 《Tetrahedron letters》1981,22(32):3043-3046
A variety of β-dicarbonyl compounds can be converted to the corresponding unsaturated derivatives in high yields. The process involves reaction of the β-dicarbonyl carbanion with Se metal, followed by alkylation with methyl iodide to form the methylseleno derivative and subsequent oxidative elimination. 相似文献
9.
ZrOCl2 · 8H2O catalyzes the one-pot synthesis of β′-acetamido-β-dicarbonyl compounds in high yields from aldehyde, enolizable β-dicarbonyl compound, acetyl chloride, and acetonitrile in solvent as well as in solvent-free conditions. β′-Acetamido-β-ketoesters are formed in moderate to exclusive pref-diastereoselectivity. 相似文献
10.
Starting from trifluoromethyl β-dicarbonyl compounds, a rare loss of CF3CO was observed in the amination reactions performed under heterogeneous conditions using NsONHCO2Et as the aminating agent and CaO or NaH as the base, while corresponding nonfluorinated β-dicarbonyl compounds under analogous conditions give non deacylated aminated compounds. This reaction can facilitate a direct synthesis of N-substituted α-amino esters or α-amino ketones. 相似文献
11.
A direct α-amination of β-dicarbonyl compounds has been achieved by using iodosobenzene (PhIO) as an oxidant and p-toluenesulfonamide (TsNH(2)) as an aminating reagent in the presence of a catalytic amount of perchlorate zinc hexahydrate. The present amination reaction proceeds quickly at rt (<30 min needed for most tested substrates) to provide the corresponding α-N-tosylamido β-dicarbonyl compounds in high to excellent yields. 相似文献
12.
Rahim Hekmatshoar Sodeh Sadjadi Samaheh Sadjadi Majid M. Heravi Yahya S. Beheshtiha Fatemeh F. Bamoharram 《合成通讯》2013,43(11):1708-1716
An efficient synthetic method of six- and five-member nitrogen heterocyclic compounds was developed. Nitrogen heterocyclic compounds were prepared by condensation of the β-dicarbonyl compounds with the corresponding β- or γ-amino alcohols, subsequent cyclization, and spontaneous aromatization in the presence of a catalytic amount of Keggin-type heteropoly acids under very mild conditions. 相似文献
13.
14.
Reaction of trimethylsilylenol ethers and Vilsmeier's reagent leads to the corresponding regiocontrolled β-dicarbonyl compounds with high to good yields. 相似文献
15.
《Tetrahedron》1988,44(23):7185-7192
The reactions of 1,2-diaminobenzimidazoles with β-dicarbonyl compounds give 1,2,4-triazepino [2,3-a]benzimidazole and pyrimido [1,2-a]benzimidazole-derivatives. 相似文献
16.
等价基团在合成1,4-二羰基化合物上的应用 总被引:1,自引:1,他引:0
本文论述了等价基因在合成1,4-二羰基化合物上的应用。分别讨论了酰基负离子、α-酰基碳正离子和β-酰基碳负离子的各类等价基团。 相似文献
17.
A simple, practical, and convenient fluorination of 1,3-dicarbonyl compounds was achieved by direct use of aqueous hydrofluoric acid and iodosylbenzene (PhIO). The reaction of ethyl benzoylacetate with the reagent system of aqueous HF and PhIO in CH(2)Cl(2) gave ethyl 2-fluoro-2-benzolyacetate in 98% yield. Other 1,3-dicarbonyl compounds including β-keto esters and 1,3-diketones underwent the fluorination reaction to give the corresponding fluorinated products in good yields. 相似文献
18.
Russian Journal of Organic Chemistry - Maghemite–copper oxide nanocomposite catalyzed oxidative coupling of formamides with β-dicarbonyl compounds in the presence of tert-butyl... 相似文献
19.
Enol phosphates and enol tosilates of β-dicarbonyl compounds react with lithium organoselenolates to give β-organoseleno (Z)-α,β-unsaturated carbonyl compounds. Tetrasubstituted vinylic vic-bis(organylchalcogenides) of (E)-geometry have been prepared by this method. 相似文献
20.
The highly efficient direct addition of β-dicarbonyl compounds to secondary alcohols has been achieved using one of the cheapest acids, H2SO4, as the catalyst. For a series of β-dicarbonyl compounds and various secondary alcohols, the addition reactions all complete in 5 min with high yields both under the conventional heating condition and under the microwave heating condition. The comparison of the results obtained from the microwave heating condition with those obtained from the conventional heating condition shows that no obvious specific or nonthermal microwave effects exist in the microwave-assisted addition reactions. 相似文献