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651.
A ligand-free Cu-catalyzed protocol for the Ullmann-type N-arylation of N-containing heterocycles with aryl or heteroaryl iodides and bromides has been established. A broad range of functional groups is well tolerated on both of the cross-coupling partners, producing the desired products in good to excellent yields. 相似文献
652.
Rajan Abraham 《Tetrahedron letters》2017,58(31):3057-3063
Aryl bis(thiazole-2-imine)methanes have been synthesized chemoselectively for the first time by an unusual reaction between 5-aryl substituted 2-aminothiazoles and aromatic aldehydes with excellent yield using inexpensive and easy available acetic acid as a catalyst under mild conditions. The present protocol was constructed through N-C bond formation by the condensation and nucleophilic addition reactions. 相似文献
653.
A simple procedure for the synthesis of organo-chalcogenides has been developed by the reaction of aryl/heteroaryl amines with di-aryl/heteroaryl dichalcogenides in the presence of tBuONO and Fe(0) nanoparticles. The reaction proceeds via in situ diazotization followed by chalcogenation. A series of functionalized diaryl/aryl heteroaryl/diheteroaryl/aryl-alkyl selenides, sulfides and tellurides have been obtained by this procedure. Significantly, using this procedure 2,4-dinitroaniline is converted to (2,4-dinitrophenyl)(phenyl)selane which is known as thioredoxin reductase (TR) and glutathione reductase (GR) inhibitor. The reaction goes by a radical pathway and a plausible mechanism has been suggested. 相似文献
654.
Pratip Kumar Dutta Arpi Majumder Sanjay Dutta Basab Bijayi Dhar Parthapratim Munshi Subhabrata Sen 《Tetrahedron letters》2017,58(6):527-530
An efficient solvent free Pd(pCH2S)2dba catalyzed green-chemical strategy for the synthesis of diaryl disulfides from aryl thiols in moderate to excellent yield is reported. Variety of diaryl disulfides were synthesized. The catalyst is recyclable up to four cycles. 相似文献
655.
A novel visible-light (blue LEDs: hν = 425 ± 15 nm) photocatalyzed one-pot method for the synthesis of electronically diverse aryl glyoxals in good to excellent yields from acetoarylones and green regents such as air, vitamin C and dioxane dibromide has been described. In addition, an application of the current methodology has been demonstrated for the oxidation of monoamine oxidase-B inhibitors, i.e., 1-(4-((4-fluorobenzyl)oxy)phenyl)ethanone and 1-(3-((4-chlorobenzyl)oxy)phenyl)ethanone. This finding may serves as a valuable alternative to the traditional acetoarylones oxidation reactions conducted using selenium dioxide a harmful and unselective reagent known to simultaneously oxidize allylic, benzylic, CH3 and so on. 相似文献
656.
Qinglin Zhang Yongbin Duan Huifeng Guo Hong Yang Jiulong Zhai Tiantian Li Zhihai Wang Xiaolei Lu Yan Wang Prof. Yan Yin 《化学:亚洲杂志》2021,16(13):1832-1838
A Bi(OTf)3-catalyed reaction of 3-aryl propargyl alcohols with sulfonamide and halogen source was firstly investigated, which provided a facile route for the synthesis of a large variety of α-halo-β-amino ketones. The key intermediates, β-amino ketones, were obtained through tandem Meyer-Schuster rearrangement reaction of propargyl alcohols and intermolecular Michael addition of α, β-unsaturated ketones and sulfonamide. Then the in situ generated α-halo-β-amino ketones underwent the base-promoted intramolecular cyclization to give diverse acyl aziridines in a one-pot fashion. These transformations are reliable on a large scale. The high yields and convenient experimental operations make it a valuable method for the construction of α-halo-β-amino ketones and acyl aziridine derivatives. 相似文献
657.
Abdelilah Takfaoui Liqin Zhao Rachid Touzani Jean-François Soulé Pierre H. Dixneuf Henri Doucet 《Tetrahedron》2014
The regioselective 2- or 5-arylation of imidazole derivatives with aryl halides using palladium catalysts has been described in recent years; whereas the arylation at both C2 and C5 carbons of imidazoles in high yields has not been performed. We found conditions allowing the access to these 2,5-diarylimidazoles via a one pot reaction. The choice of the base was found to be crucial to obtain these products in high yields. Using CsOAc as the base, DMA as the solvent and only 2 mol % of the phosphine-free Pd(OAc)2 the catalyst, the target 2,5-diarylated imidazoles were obtained in moderate to good yields with a wide variety of aryl bromides. Substituents such as fluoro, trifluoromethyl, formyl, acetyl, propionyl, ester, nitro or nitrile on the aryl bromide were tolerated. Sterically congested aryl bromides or heteroaryl bromides can also be employed. Surprisingly the nature of the substituent at position 1 on the imidazole derivative exhibits a huge influence on the reaction. 相似文献
658.
659.
Sandip N.Gavade Ravi S.Balaskar Madhav S.Mane Pramod N.Pabrekar Murlidhar S.Shingare Dhananjay V.Mane 《中国化学快报》2011,22(6):675-678
The coupling reaction of phenylurea with different functionalized aryl halides in the presence of air stable CuI,N,N-dimethylethylenediamine as a ligand,and K3PO4 as a base gives symmetrical and unsymmetrical diarylureas in relatively high yields.This method is milder than the palladium catalyzed arylation and avoids the use of toxic phosphine ligands. 相似文献
660.
The carbonylative cross coupling of aryl iodide with ortho-haloaniline to ortho-haloanilide using phosphine-free Pd(OAc)2 catalyst in water as a reaction medium has been studied. The present protocol facilitated the reaction of o-haloanilines with a wide variety of hindered and functionalized aryl iodides, affording good yields of the desired products. The protocol was also extended for the synthesis of benzoxazoles through cyclization of ortho-haloanilide using Cu(acac)2 catalyst. 相似文献