首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 281 毫秒
1.
The synthesis of 1-alkyl(aryl)-5-(3,3,3-trihalo-2-oxopropylidene)-1H-pyrrol-2(5H)-ones 5, 6a-d from 1-alkyl(aryl)-4-bromo-5-(3,3,3-trihalo-2-oxopropylidene)-1H-pyrrolidin-2-ones 3, 4a-d is reported. The 1-alkyl(aryl)-4-bromo-5-(3,3,3-trihalo-2-oxopropylidene)-1H-pyrrolidin-2-ones 3, 4a-d were obtained from regiospecific bromination of 1-alkyl(aryl)-5-(3,3,3-trihalo-2-oxopropylidene)-1H-pyrrolidin-2-ones 1, 2a-d with molecular bromine. The NMR and X-ray diffraction data showed that 1-alkyl(aryl)-5-(3,3,3-trihalo-2-oxopropylidene)-1H-pyrrolidin-2-ones were brominated at 4-position in the pyrrolidin-2-one ring.  相似文献   

2.
New heterocyclic betaines, 4-aryl-5-(alkoxycarbonyl)-2-oxo-3-(pyridin-1-ium-1-yl)-2,3-dihydro-1H-pyrrol-3-ides, were synthesized in good yields by the reaction of alkyl 2H-azirine-2-carboxylates with 2-methoxy-2-oxo-1-(pyridin-1-ium-1-yl)ethan-1-ides, generated from the corresponding pyridinium salts. The betaines exist as the NH-tautomers both in solution and in the solid state. Two molecules of the betaine form a dimer by hydrogen bonds of the type NH?O in solid state. According to TD DFT calculations the long-wave absorption band in betaines mainly corresponds to the intramolecular charge transfer between the negatively charged pyrrole unit and the positively charged pyridinium group. The blue shift of the long-wave absorption in protic solvents was adequately described in terms of H-complex formation with the nucleophilic centre of the molecular skeleton.  相似文献   

3.
A new and highly efficient method for the synthesis of 4-(benzimidazol-2-yl)quinolin-2(1H)-ones via the rearrangement of spiroquinoxalinones in moderate-to-excellent yields has been developed. The rearrangement represents a facile approach to medicinally important biheterocyclic compounds. Compared to other methods, the present protocol has a number of advantages such as – cost-effectiveness, avoidance of difficult of access quinolin-2-one and benzimidazole derivatives as reaction partners, and easy accessibility of starting materials, making it a highly practical approach to access various 4-(benzimidazol-2-yl)quinolin-2(1H)-ones.  相似文献   

4.
An efficient approach for the synthesis of 3-alkyl-8-arylamino-1H-imidazo[4,5-g]quinazolin-2(3H)-thiones and 3-alkyl-8-arylamino-1H-imidazo[4,5-g]quinazolin-2(3H)-ones on solid phase has been developed. The reaction conditions were readily amenable and the products were obtained in good yields and purities after their cleavage from the resin.  相似文献   

5.
Synthetic strategies to gain access to all four isomers of 3-(3-chloro-1H-pyrazol-5-yl)quinoxalin-2(1H)ones with monosubstituted benzo core (i.e., compounds 8ad) are described. Preparation of these heterocyclic compounds succeeded starting from only two different substituted 2-nitroanilines (i.e., 3-methoxy- and 4-methoxy-2-nitroaniline) in three or five steps, respectively.  相似文献   

6.
The synthesis of 5-heteroaryl-substituted uracil derivatives is presented. The 1,3-dipolar cycloaddition reaction was applied for the construction of a heterocyclic ring. The nitrile oxides were obtained from the appropriate 4-substituted benzaldoximes using N-chlorosuccinimide (NCS) under basic conditions. [2+3] Cycloaddition of nitrile oxides with 5-cyanouracil as a dipolarophile gave the corresponding 5-(3-substituited-1,2,4-oxadiazol-5-yl)uracils in satisfactory yields under mild conditions. 5-Substituted uracils having an additional heterocyclic ring were obtained as a result of the [2+3] cycloaddition of 5-cyanouracil to nitrile oxides generated from thiophene-2-carbaldehyde and 5-formyluracil derivatives.  相似文献   

7.
Double asymmetric induction in Michael reactions has been studied. Enantioselective alkylation of a cyclic ketone (1-indanone) with α-phenyl-nor-gramine was carried out. The relative configuration of (2S)-2-[(R)-1H-indol-3-yl(phenyl)methyl]-2,3-dihydro-1H-inden-1-one was established by X-ray diffraction. The relative configuration of (R,R,S)- and (S,R,S)-2-1H-indol-3-yl(phenyl)methyl]-2,3-dihydro-1H-inden-1-ols was established by 1H NMR studies.  相似文献   

8.
Expanded 5-(hetero)aryl-thien-2-yl substituted 3-ethynyl quinoxaline dyes with variable substitution pattern on the peripheral thiophene ring were synthesized in moderate to very good yields by Suzuki and Buchwald-Hartwig coupling of the corresponding brominated 3-ethynyl quinoxalines. Dumbbell-shaped bis(thienyl 3-ethynyl quinoxalines) are also accessible by the Suzuki protocol. The photophysical properties were investigated by UV and fluorescence spectroscopy. Most of the obtained compounds display fluorescence in solution and some of them also in the solid state. Additionally, tuning of the emission color of the quinoxaline based chromophores can be conveniently accomplished by the remote substituent group. The determined absorption and emission maximum as well as the Stokes shifts strongly correlate with Hammett σp+parameters. Besides,photophysical properties of selected derivatives in the solid state, biphasic solutions, and PMMA films, along with their relationships, are comparatively investigated. Moreover, two 5-(hetero)aryl-thien-2-yl substituted 3-ethynyl quinoxaline dyes are aggregation induced emission(AIE) chromophores indicated by restriction of molecular motions. A covalently restricted 3-ethynyl quinoxaline supports that the inhibition of molecular rotation is responsible for the significant enhancement of fluorescence in acetonitrile/water mixtures.  相似文献   

9.
A new approach to the regioselective synthesis of polyfunctional 3H-pyrroles from 4-oxoalkane-1,1,2,2-tetracarbonitriles is described. 5-Amino-3-(2-aryl-2-oxoethyl)-3H-pyrrol-3,4-dicarbonitriles are prepared from 4-aryl-4-oxobutane-1,1,2,2-tetracarbonitriles. Diastereomeric 5-amino-2-morpholin-4-yl-3-(2-oxocyclohexyl)-3H-pyrrole-3,4-dicarbonitriles were obtained from 1-(2-oxocyclohexyl)ethane-1,1,2,2-tetracarbonitriles.  相似文献   

10.
1-Hydroxy-9,9a-dihydro-1H-imidazo[1,2-a]indol-2(3H)-ones, as a new type of azaheterocyclic hydroxamic acids, have been synthesized regioselectively from 1-carbamoylmethyl- or 1-(methoxycarbonyl)methyl-2,3,3-trimethyl-3H-indolium salts by reaction with hydroxylamine in the presence of a strong base. The alkylation and reduction with sodium borohydride of these novel heterocycles have been investigated. When treated with protic acids 1-hydroxy- or 1-alkoxy-9,9a-dihydro-1H-imidazo[1,2-a]indol-2(3H)-ones underwent ring opening of the imidazolidine to afford 1-[2-(hydroxyamino)-2-oxoethyl]-2,3,3-trimethyl-3H-indolium salts. The structural assignments are based on extensive 1H, 13C and 15N NMR spectroscopic studies and single crystal X-ray analyses.  相似文献   

11.
Reaction of 1-{[1-(2-nitrophenyl)-1H-pyrrol-2-yl]sulfonyl}acetone with sodium hydroxide with or without zinc gave 1-(2-nitrophenyl)(1H-pyrrol-2-ylsulfonyl)methane by a Truce-Smiles type of transformation and 1-(2-nitrophenyl)-2-methylsulfonylpyrrole by deacetylation. Similar treatment of 1-{[1-(2-nitrophenyl)-1H-pyrrol-2-yl]sulfinyl}acetone gave only 1-(2-nitro-phenyl)(1H-pyrrol-2-ylsulfinyl)methane. 1-{[1-(2-Nitrophenyl)-1H-pyrrol-2-yl]sulfanyl}acetone, 2-{[1-(2-nitrophenyl)-1H-pyrrol-2-yl]sulfanyl}-1-phenyl-ethan-1-one or 2-{[1-(2-nitrophenyl)-1H-pyrrol-2-yl]sulfanyl}acetonitrile were reductively cyclised with sodium borohydride and 5% palladium-on-carbon into 6-methyl(or phenyl)-5,6-dihydro-7H-pyrrolo[1,2-a][3.1.6]benzothiadiazocin-7-ol or 6-amino-5H-pyrrolo[1,2-a][3.1.6]benzothiadiazocine-7-oxide, respectively.  相似文献   

12.
A practical and expedient synthesis of the title compounds is described. They were prepared by Stille reaction of nitro halopyridines 4 or nitro fluro-halobenzenes 10, followed by Michael addition of tert-butyl 4-aminopiperidine-1-carboxylate to the resulting activated vinyl compounds 5 and 11, hydrogenation (-NO2→-NH2), cyclic urea formation, Boc removal, and HCl salt formation. However, N3 and F1 analogs could not be made by this general strategy. Activated vinyl compounds 5a and 5d when reacted with tert-butyl 4-aminopiperidine-1-carboxylate did not stop at the desired Michael addition stage; but proceeded to produce azaindolines 8 and 9. Michael addition did not occur to compound 11d; instead, the fluorine atom was displaced.  相似文献   

13.
The Knoevenagel condensation of pyrrole-2-carboxaldehyde (1) with a range of substituted benzyl nitriles (2a-e) afforded rapid access to a family of α,β-unsaturated nitriles (3a-e) in good yields (67-78%). Flow hydrogenation (ThalesNano H-cube™) at 60 °C, 50 bar H2 pressure, 1.0 mL/min through a 10% Pd-C catalyst selectively, and quantitatively, hydrogenated the olefin double bond (4a-e). Use of a Raney Nickel catalyst at 70 °C, 70 bar H2 pressure and flow rates of 0.5-1.0 mL/min afforded quantitative conversion into the corresponding saturated amines with the reduction of both the olefin and nitrile bonds (5a-e). The versatility of this approach was further exemplified by reaction of 5a and 5c with norcantharidin to afford acid amide norcantharidin analogues 7 and 8 as novel protein phosphatase 1 and 2A inhibitors.  相似文献   

14.
Three-component reaction of 2-alkynylbenzaldehyde, malononitrile, and indole under mild conditions is described, which generates the desired (Z)-1-benzylidene-3-(1H-indol-1-yl)-1H-indene-2,2(3H)-dicarbonitriles in moderate to good yields. This reaction proceeds smoothly with high selectivity. The tandem condensation, nucleophilic addition, and 5-exo-cyclization may be involved in the process.  相似文献   

15.
An efficient approach to chiral α-hydroxy acid esters by Lewis acid-mediated asymmetric [1,5]-hydride shift and isomerization of 2-(3-pyrroline-1-yl)arylketone acid ester has been achieved in up to 96% yield and 94% ee. This protocol would be applied in the synthesis of chiral α-hydroxy acid derivatives with simplicity and high enantioselectivity.  相似文献   

16.
Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.  相似文献   

17.
Bilirubin oxidation end products (BOXes) show significant physiological effects and are connected to severe diseases such as subarachnoid hemorrhage induced cerebral vasospasm. BOX B (2-(4-ethenyl-3-methyl-5-oxo-1,5-dihydro-2H-pyrrol-2-ylidene)ethanamide) was prepared via a five-step synthesis starting from methyl (4-bromo-3-methyl-5-oxofuran-2(5H)-ylidene)ethanoate that was vinylated and then reacted with NH4OAc, LiOH, (COCl)2, and finally with ammonia yielding Z-BOX B. Derivatives of Z-BOX A and Z-BOX B with [15N]labeled lactam rings were synthesized accordingly.  相似文献   

18.
《Tetrahedron letters》2004,45(21):3999-4001
A new application of the Ugi reaction in the synthesis of heterocyclic compounds is described. Substituted quinolin-2-(1H)-ones are formed in one-pot sequential Ugi four-component condensation and intramolecular Knoevenagel cyclization between o-acylanilines, aldehydes, malonic or tosylacetic acids and cyclohexyl isocyanide.  相似文献   

19.
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   

20.
11H-Indeno[1,2-b]quinoxalin-11-ones generated in situ from ninhydrin and various 1,2-phenylenediamines, catalysed by montmorillonite K10 under microwave irradiation, condense with 4-hydroxyproline to produce 11-(1H-pyrrol-1-yl)-11H-indeno[1,2-b]quinoxaline derivatives in good yields.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号