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1.
An efficient method for preparation of the arylaminotetrazoles derivatives is reported using aluminium chloride as an effective Lewis acid. Generally, 5-arylamino-1H-tetrazole isomer can be obtained from arylcyanamides carrying electron-withdrawing substituents on the aryl ring. As the electropositivity of the substituent is increased, the product is shifted toward the formation of 1-aryl-5-amino-1H-tetrazole isomer.  相似文献   

2.
Davood Habibi 《合成通讯》2013,43(21):3159-3167
An efficient method for preparation of 5-arylamino-1H-tetrazole and 1-aryl-5-amino-1H-tetrazole derivatives is reported using FeCl3-SiO2 as an effective heterogeneous catalyst. Generally, when the substituent in arylcyanamide is a strongly electron-withdrawing group, the position of the equilibrium would shift toward 5-arylamino-1H-tetrazole, whereas with an electron-releasing substituent, the position of the equilibrium would shift toward 1-aryl-5-amino-1H-tetrazole.  相似文献   

3.
An efficient method for preparation of arylaminotetrazoles is reported using natrolite zeolite as a natural catalyst. Generally, isomer of 5-arylamino-1H-tetrazole can be obtained from arylcyanamides carrying electron-withdrawing substituent on aryl ring and as the electropositivity of substituent is increased, the product is shifted toward the isomer of 1-aryl-5-amino-1H-tetrazole. This method has the advantages of high yields, simple methodology, short reaction times and easy work-up. The catalyst can be recovered by simple filtration and reused in good yields.  相似文献   

4.
An efficient method for the preparation of 5-substituted 1H-tetrazole derivatives is reported using FeCl3-SiO2 as an effective heterogeneous catalyst. This method has the advantages of high yields, simple methodology, and easy work-up. The catalyst can be recovered by simple filtration and reused delivering good yields.  相似文献   

5.
Jack Maung 《Tetrahedron letters》2004,45(34):6497-6499
5-Ethylthio-1-H-tetrazole (SET) and 4,5-dicyanoimidazole (DCI) were examined as alternatives to 1-H-tetrazole to mediate the synthesis of phosphonate diesters and phosphonamidates from phosphonyl dichlorides through a two-step one-pot reaction in various organic solvents. SET and DCI were comparable to 1-H-tetrazole for catalyzing these reactions. SET afforded slightly greater yields than DCI while benzene was universally the best solvent for this reaction.  相似文献   

6.
A simple and efficient protocol is developed for the synthesis of 5-substituted 1H-tetrazole derivatives from various nitriles and sodium azide (NaN3) via [3+2] cycloaddition reaction using B(C6F5)3 as a catalyst. The present synthetic method displayed significant advantages such as low catalyst loading, mild reaction conditions, low toxicity, easy work-up, high yields, and compatibility with other functional groups.  相似文献   

7.
A simple and efficient protocol is developed for the synthesis of 5-substituted 1H-tetrazoles from various oximes and sodium azide (NaN3) by using copper acetate as a catalyst.  相似文献   

8.
This work describes the first and unprecedented examples of inverse electron demand Diels-Alder reactions of 5-(1-nitrosovinyl)-1-phenyl-1H-tetrazole, generated in situ from the corresponding bromooxime, with electron rich alkenes and heterocycles, providing in good overall yields tetrazolyl-1,2-oxazines and -oximes. Upon subsequent reduction these allowed the access to 5-(1-aminoalkyl)-1H-tetrazoles, paving the way for a new entry into this important class of compounds, bioisosteres of α-amino acids.  相似文献   

9.
<正>An efficient and simple method for the preparation of 5-arylamino-1H-tetrazole and 1-aryl-5-amino-1H-tetrazole derivatives is reported using aluminum(Ⅲ) hydrogensulfate(Al(HSO_4)_3) as an effective heterogeneous catalyst from secondary arylcyanamides. Generally,when the substitution in arylcyanamide is strongly electron-withdrawing the position of equilibrium would shift toward the isomer of 1-aryl-5-amino-1H-tetrazole(B) and as the electron-donating of substituent increased,the position of equilibrium is shifted toward the isomer of 5-arylamino-1H-tetrazole(A).The present methodology offers several advantages,such as excellent yields,short reaction times,easy work-up and greener conditions.  相似文献   

10.
New 2-aryl-6-(arylamino)-1H-imidazo[1,2-b]pyrazole-7-carbonitriles are synthesized in good yields, via cyclocondensation of 5-amino-1-(2-oxo-2-arylethyl)-3-(arylamino)-1H-pyrazole-4-carbonitriles, which are prepared by the reaction of 5-amino-3-arylamino-1H-pyrazole-4-carbonitriles and α-bromoacetophenone derivatives in the presence of K2CO3 using acetone as the solvent.  相似文献   

11.
In this study, a novel and convenient route for the construction of 5-((1H-1,2,4-triazol-1-yl)methyl)-1H-indoles (8) is presented starting from (1H-1,2,4-triazol-1-yl)methanol (5) and indolines (6) under 98% H2SO4 at room temperature for 4–24 h, followed by deacetylation and dehydrogenation. Based on this finding, a novel route to synthesize Rizatriptan starting from tryptamine was designed and accomplished with 48.5% overall yield in 6 steps. Compared with operational art, the new route afforded higher yield and more pure products requiring no chromatographic purification, which may further be applied in industrialization.  相似文献   

12.
A series of 1-aryl-5-benzyl-1H-tetrazoles has been obtained during the reaction of 1-aryl-5-methyl-1H-tetrazoles with 1,2-dehydrobenzene. The mechanism of product formation was investigated.  相似文献   

13.
Various 3-(hetero)aryl, 3-alkyl and 3-alkenyl-2(1H)-pyrazinones were prepared by applying the Suzuki and Heck reaction methodology to 3,5-dichloro-2(1H)-pyrazinones. Furthermore, following hydrogenolysis of the 5-chloro substituent and regioselective 5-bromination, this palladium-catalysed cross-coupling approach could be extended to the synthesis of the analogous 5-substituted 2(1H)-pyrazinones.  相似文献   

14.
A new synthesis of 2,3-dialkyl-4-carbomethoxyisoquinolin-1(2H)-ones and 6,7-dialkyl-8-carbomethoxy-1,6-naphthyridin-5(6H)-ones is reported. The process involves treatment of a β-enaminoester with 2-fluoro-5-nitrobenzoyl chloride, 2-fluorobenzoyl chloride or 2-chloronicotinoyl chloride followed by heating in the presence of base. The conversion, which proceeds by an N-acylation-SNAr reaction sequence, affords 50–86% yields when R1 is n-alkyl but ≤30% yields when R1 is α-branched.  相似文献   

15.
The palladium-catalyzed cross-coupling reactions of 5-tributylstannyl-4-fluoro-1H-pyrazole with aryl iodides provided high yields of the corresponding 5-aryl-4-fluoro-1H-pyrazoles. Furthermore, these cross-coupling reactions proceeded smoothly under an atmosphere of carbon monoxide (CO) to afford the corresponding 5-acyl-4-fluoro-1H-pyrazoles as CO-insertion products.  相似文献   

16.
In this Letter we wish to report a simple and efficient synthetic protocol for the synthesis of 5-substituted 1H-tetrazole derivatives through the [2+3] cycloaddition of nitriles with sodium azide using ceric ammonium nitrate supported HY-zeolite as a novel catalyst. Excellent yields of the corresponding tetrazoles were obtained through this cost-effective protocol under aerobic conditions with shorter reaction time under mild reaction conditions.  相似文献   

17.
Ceric ammonium nitrate (CAN) is found to be a suitable, inexpensive, and effective non-toxic catalyst for a smooth (3+2) cycloaddition of organic nitriles with NaN3 to afford 5-substituted 1H-tetrazoles in excellent yields. Shorter reaction times, easy work-up, and substantial and pure product formation are the key advantages of the present method.  相似文献   

18.
The polyketide secondary metabolites spongosoritin A and gracilioethers A–C contain a unique methyl [2(5H)-furanylidene]ethanoate core. A synthetic model of a suspected biosynthetic intermediate to these natural products was constructed in seven steps and 48% overall yield. This model undergoes a facile cyclisation/double dehydration cascade to give the desired furanylidene motif, with the required (2Z) isomer obtained in >90 dr when an ethyl substituent is located at C3′ of the furanylidene.  相似文献   

19.

Abstract  

Arylaminotetrazoles were efficiently synthesized from secondary arylcyanamides by application of ZnCl2/AlCl3/silica as a reusable heterogeneous Lewis acid catalyst. 5-Arylamino-1H-tetrazoles can be obtained from arylcyanamides carrying electron-withdrawing substituents on the aryl ring, while with electron-releasing groups 1-aryl-5-amino-1H-tetrazoles will be produced. The former isomer is also produced within longer reaction times (~20 h) even with electron-releasing groups.  相似文献   

20.
A simple and efficient synthesis of 2-(cyclohexylamino)-6,7-dihydro-3-aryl-1H-indole-4(5H)-ones was achieved via a one-pot multi-component reaction of cyclohexyl isocyanide, an aldehyde, a 1,3-dicarbonyl compound, and ammonium acetate in the presence of a catalytic amount of KHSO4 in acetonitrile.  相似文献   

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