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11.
A novel route for the synthesis of thiazolo[3,2-a]pyrimidin-7-ones and pyrido[1,2-a]pyrimidin-2-ones from acetylated 2aminothiazoles and 2-aminopyridines under Vilsmeier conditions has been developed.The plausible mechanism has also been proposed. 相似文献
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Azza M. El-Kazak Nasser M. El-Gohary Al-Shimaa Badran Magdy A. Ibrahim 《Tetrahedron》2019,75(29):3923-3932
Vilsmeier-Haack formylation of 3-acetyl-4-hydroxycoumarin (1) afforded the unexpected 3-chloro-3-(4-chlorocoumarin-3-yl)prop-2-enal (3). Compound 3 reacted with p-toluidine and benzylamine producing Schiff base 4 and enamine 6, respectively. Treatment of compound 3 with hydrazine hydrate produced bis-coumarin 15 which upon treating with hydrazine hydrate afforded bis chromeno[4,3-c]pyrazole derivative 16. Compound 3 reacted with cyanoacetohydrazide under different conditions. Condensation of compound 3 with some heterocyclic amines and 1,2-N,N-binucleophiles was studied. Structures of the new synthesized products were deduced on the basis of their analytical and spectral data. 相似文献
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Al’bina I. Mikhaleva Andrey V. Ivanov Alexander M. Vasil’tsov 《Tetrahedron letters》2006,47(22):3693-3696
1-Vinylpyrrole-2-carbaldehydes and 1-vinyl-4,5-dihydrobenzo[g]indole-2-carbaldehyde were synthesized in 56-91% yields from their 1-vinyl derivatives by a modified Vilsmeier-Haack reaction. A low temperature (−78 °C) is required to avoid removal of the N-vinyl group, whereas at elevated temperature (reflux in 1,2-dichloroethane) the latter process leads to direct conversion of 1-vinylpyrroles to pyrrole-2-carbaldehydes. 相似文献
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Jairo Quiroga Jorge Trilleras Rodrigo Abonía Antonio Marchal 《Tetrahedron letters》2008,49(20):3257-3259
The microwave-induced synthesis of pyrazolo[3,4-d]pyrimidines 4 in the reaction of N4-substituted-2,4-diamino-6-chloro-5-carbaldehydes 3 with hydrazine is described here. Precursors 3 have been prepared by the mono-amination of 2-amino-4,6-dichloropyrimidine-5-carbaldehyde 2 with aliphatic and aromatic amines. The reaction times with primary amines were relatively shorter than for secondary amines. 相似文献
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A convenient synthesis of 1-alkyl-2-chloro-1H-indole-3-carbaldehyde oximes(5a―5d) and 1-alkyl-2-phenoxy-1H-indole-3-carbaldehyde oximes(6a―6d) from 2-indolone was completed via the Vilsmeier-Haack reac-tion,with N-alkylation and oximation as the key steps.An improved one-pot method for the synthesis of 1-alkyl-2-alkoxy-1H-indole-3-carbaldehyde oximes(7a―7h) from 1-alkyl-2-chloro-1H-indole-3-carbaldehydes(3a―3d) was described.The Williamson reactions and esterification reactions were performed and the oxime-... 相似文献
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Summary We report herein the fabrication of a simple and price-affordable portable reaction station for use in parallel solution-phase
synthesis. This homemade device uses currently available laboratory components and equipment. Specifically designed to fit
standard magnetic hotplates/stirrers, it can simultaneously hold up to 24 heated and magnetically stirred glass reactors of
both 10 and 50 mL capacities. Glass reactors are connected by flexible 16-gauge metal needles to a central gas manifold equipped
with an inlet/outlet for vacuum and inert gases. Reaction temperatures can be optimally varied from −78 ∘C to 150 ∘C. Using a statistical screening DOE method, this parallel array reactor station has been successfully operated to optimize
the one-step deprotective O-formylation of a sterically hindered bis-O-tert-butyldiphenylsilyl (O-TBDPS) aromatic diol. The latter transformation was mediated by the Vilsmeier-Haack reagent POCl3⋅DMF using a range of Lewis acid and metal salt promoters, including their binary combinations. 相似文献
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Formamidine derivatives could be used as the building blocks for substituted heterocyclic compounds with various biological activities.N’-Aryl-N,N-dimethylformamidinium chlorides have been synthesized in high yields by reaction of aromatic primary amines with Vilsmeier-Haack reagent at room temperature.The structures of all the new compounds were identified by ESI-MS,IR and NMR spectra.The steric structures of some of these compounds were clarified by X-ray single crystal analysis. 相似文献
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