共查询到20条相似文献,搜索用时 15 毫秒
1.
M.Manuel Oliveira LuisM. Carvalho Corinne Moustrou Andr Samat Robert Guglielmetti AnaM.F. Oliveira‐Campos 《Helvetica chimica acta》2001,84(5):1163-1171
The synthesis and photochromic properties of new 2,2‐diphenyl‐2H‐1‐benzopyrans, fused to an indole moiety, are described. All compounds exhibit photochromic behaviour in solution at room temperature. The heteroanellation effects are variable and depend on the position and geometry of the fused indole moiety. A general bathochromic shift in the spectra of the open forms is observed. The presence of a N‐methyl group prevents the broadening of the absorption spectra and promotes the instability of some photoinduced forms of compounds with the indole moiety fused at the 5,6 positions of the 2H‐1‐benzopyran skeleton. The enhanced photocolouration efficiency in the near‐UV and the kinetics of thermal bleaching indicate that the novel compounds with an indole moiety fused at the 6,7 positions, particularly those with a linked thiophene moiety, are very interesting molecules for applications in the field of variable optical absorption systems. 相似文献
2.
N. Sh. Lomadze I. Sh. Chikvaidze N. L. Targamadze L. N. Kurkovskaya Sh. A. Samsoniya N. N. Suvorov 《Chemistry of Heterocyclic Compounds》1994,30(9):1034-1038
Electrophilic substitutions of 2,7-dicarbethoy-1H,6H-pyrrolo[2,3-e]indole (Friedel-Crafts acylation, nitration, bromination) take place both at position 3 of the indole ring and at positions 5 and 8 in the benzene ring.For communication 15 see [1].Iv. Dzhavakhishvili State University, Tbilisi 380028. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1197–1201, September, 1994. Original article submitted July 5, 1994. 相似文献
3.
Single crystal EPR and phosphorescence studies of indene, indole, benzofuran and coumarin were made using DBB host. It was shown unambiguously that D < 3 |E| for these systems. (Z axis is perpendicular to the molecular plane.) The directions of the magnetic axes were also determined. Spin densities at the 6 and 5 positions in indole were estimated and compared with those of other substituted benzenes. It is concluded that large spin density is located at the CC group. 相似文献
4.
D. O. Kadzhrishvili Sh. A. Samsoniya E. N. Gordeev L. N. Kurkovskaya V. E. Zhigachev N. N. Suvorov 《Chemistry of Heterocyclic Compounds》1983,19(8):871-876
The principles of the electron density distribution in 1H,5H-pyrrolo [2,3-f]indole and 3H,6H-pyrrolo[3,2-e]indole molecules were determined on the basis of quantumchemical calculations. These results were confirmed by the results of the investigated electrophilic-substitution reactions. The reaction centers of these compounds proved to be the same positions as in indole, viz., the 3 and 7 and 1 and 8 positions, respectively. The impossibility of 1,8-disubstitution in the angular heteroring was demonstrated in the case of bulky substituents; this was explained by a steric effect.See [1] for communication 7.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1086–1091, August, 1983. 相似文献
5.
Robert B. Hermann 《International journal of quantum chemistry》1968,2(1):165-177
Two molecular-orbital methods—extended Hückel theory and CNDO /2—have been used to estimate the relative electrophilic reactivities of the alpha and beta positions in the nonalternant heterocyclic compounds pyrrole, indole, furan, and benzofuran by comparing total transition-state energies. The order of basicities of three positions of indole and pyrrole are predicted. Charge densities are also calculated and evaluated in the light of n.m.r. chemical shift data. 相似文献
6.
Carol L. Ladner Khai Tran Mary Le Raymond J. Turner Robert A. Edwards 《Photochemistry and photobiology》2014,90(5):1027-1033
Photoreaction of indole containing compounds with chloroform and other trichlorocompounds generates products with redshifted fluorescence. In proteins, this reaction can be used for the fluorescent detection of proteins. Little characterization of products generated through the photochemical reaction of indoles with halocompounds has been done, yet is fundamental for the development of other fluorophores, protein labeling agents, and bioactive indole derivatives. Here, we have characterized which isomers form in the photoreaction between tryptophan and chloroform using 1H‐NMR of tryptophan and methylated derivatives to reveal that the two major products that are formed result from modification at the 4‐ and 6‐carbon positions of the indole ring. Reaction at position 6 generates 6‐formyl tryptophan and the reaction at position 4 generates an imine because the formyl derivative that is initially formed reacts further with the tryptophan amine group. The spectroscopic properties and product molecular weights of photoproducts formed from photoreaction of tryptophan with other trihalo and monohalocompounds are also determined. The indole ring of tryptophan can be modified with various additions from halocompounds, including the addition of labels to the indole ring via methylene groups. This opens possibilities for generating novel tryptophan based fluorophores and protein labeling strategies using this photochemistry. 相似文献
7.
The reactivity of indole derivatives towards nitrilimines has been studied. Substituents at positions 1, 2 and 3 of the indole ring greatly affect the course of the reaction. 1,3-Dipolar cycloaddition products (3a,8a,dihydropyrazole-[3,4-b]-indole derivatives) and non-cyclic addition products (3-indolyl derivatives) were obtained depending on these substituents. The structures reported were assigned on the basis of satisfactory analytical, spectroscopic and chemical data. 相似文献
8.
Sh. A. Samsoniya N. L. Targamadze L. N. Kurkovskaya Dzh. A. Kereselidze N. N. Suvorov 《Chemistry of Heterocyclic Compounds》1980,16(5):495-500
As expected, the 3 and 8 positions are the reaction centers of 1H, 6H-pyrrolo-[2, 3-e] indole in the Vilsmeier-Haack and Mannich reactions. Diazo coupling takes place primarily in the 3 position and leads primarily to monosubstitution products. 6,8-Diacetyl-1H,6H-pyrrolo [2,3-e]indole and 1,8-diacetyl-1H, 6H-pyrrolo-[2,3-e] indole were isolated from the acetylation products.See [1] for communication 1.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 639–644, May, 1980. 相似文献
9.
We report a highly diastereoselective approach for the synthesis of the pentacyclic indole core of the manadomanzamine alkaloid skeleton, with complete control over the relative and absolute stereochemistries at the three contiguous stereocentres at ring positions 1, 10, and 24, from a readily available chiral template. 相似文献
10.
Kessler A Coleman CM Charoenying P O'Shea DF 《The Journal of organic chemistry》2004,69(23):7836-7846
An effective synthesis of the functionalized indole ring system has been developed from substituted o-aminostyrene starting material. Our methodology involves a novel cascade reaction sequence of alkyllithium addition to the styrene double bond and subsequent trapping of the intermediate organolithium with a suitable electrophile, followed by an in situ ring closure and dehydration to generate the indole ring. This new reaction sequence allows for the introduction of molecular diversity at all positions on the indole scaffold. The procedure was shown to be successful with a range of both C and N substituents on the o-aminostyrenes. The reaction sequence was tolerant to the reactivity range of alkyllithiums such as tert-, sec-, and n-butyllithium. The electrophiles used were DMF, which generated indole products with C-2 unsubstituted, and nitriles, which incorporated the nitrile substituent at C-2. The o-aminostyrene starting materials were generated by a Pd-catalyzed cross-coupling reaction of a vinyl boronic acid equivalent with the readily available substituted o-bromoanilines. 相似文献
11.
G. S. Katrukha I. G. Smirnova A. B. Silaev T. E. Kuz'menko 《Chemistry of Natural Compounds》1976,10(5):645-647
Summary 1. Derivatives of the polypeptide antibiotic A-128-OP at positions 1, 2, and 3 of the indole rings of the -methyltryptophan and dehydrotryptophan residues have been obtained for the first time, and their physicochemical properties have been studied.2. The introduction into the antibiotic molecule of a 2-hydroxy-5-nitrobenzyl or a 2-nitrophenyl-sulfenyl substituent lower its antibacterial activity 15- to 20-fold. The replacement of the hydrogen atoms in positions 1 of the indole rings of the -methyltryptophan and dehydrotryptophan residues leads to a 4-to 5-fold decrease in the activity of antibiotic A-128-OP.M. V. Lomonosov State University. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 636–639, September–October, 1974. 相似文献
12.
Alan R. Katritzky Malgorzata Drewniak-Deyrup Xiangfu Lan Frederic Brunner 《Journal of heterocyclic chemistry》1989,26(3):829-836
Indole, carbazole, pyrrole, imidazole, benzimidazole, 2-methyl- and 2-phenylbenzimidazole, and 1, 2, 4-triazole have each been converted into their N-(benzotriazol-1-ylmethyl) derivatives. The pyrrole, indole, and carbazole adducts undergo smooth lithiation at the inter-ring methylene group and subsequent reaction there with electrophiles. For the imidazole, benzimidazole, and triazole systems, lithiations at other molecular positions competed. 相似文献
13.
A strategy for the synthesis of 2,3-disubstituted indole derivatives based on an intramolecular carbopalladation-anion capture cascade has been developed, wherein construction of the pyrrole ring and functionalisation of the indole C2 and C3 positions were achieved by extensive use of palladium(0)-catalysed coupling reactions. 相似文献
14.
The magnetic circular dichroism spectra of a number of indole alkaloids show two B-terms of opposite sign in the 250–330 nm wavelength region associated with the 1Lb and 1La electronic transitions, the long wavelength, 1Lb, band being of positive sign, whereas both bands strongly overlap in absorption. Various substituents in different positions of the indole ring cause a red shift of both bands and a broadening of the long wavelength B-term. The sign pattern, howver, remains unchanged in all examples thus far investigated. Dihydroindole and oxindole, on the other hand, exhibit MCD. bands with the opposite sign sequence as compared to the indole chromophore. This observation allows identification of the indole chromophore in alkaloids from the sign pattern of the MCD. bands. 相似文献
15.
Hanumant B. Borate Sangmeshwer P. Sawargave Suleman R. Maujan 《Tetrahedron letters》2009,50(47):6562-6566
A short synthetic strategy for 3,6-disubstituted-N-2-thienyl/aryl-indoles, involving reaction of substituted 2,4-difluoro/dichloro-styrene epoxide with substituted 2-formylaminothiophenes or substituted N-formylanilines in the presence of a base followed by treatment with an acid, has been developed. The method was applied for the synthesis of a number of indoles with a variety of substituents at 1, 3, and 6 positions of the indole moiety. 相似文献
16.
Shyamaprosad Goswami Manas Kumar Das Annada C. Maity Ching Kheng Quah Hoong-Kun Fun 《合成通讯》2016,46(18):1529-1536
The first syntheses of indolopterin and indoloquinoxaline, two important and dissimilar diheterocycles linking C-2 of indole with C-6 of pterin (significant positions for showing biological activity), and quinoxaline, respectively, have been achieved based on two classical reactions. The introduction of a keto methyl group on to the 6-position of pterin and quinoxaline followed by Fischer indole synthesis led to these target diheterocycles. These indole-substituted diheterocycles will significantly increase the electron density on the pterin-5-N and quinoxazoline-2-N, which may change the redox properties of pterin and quinoxaline, and also the electron-withdrawing pterin or quinoxazoline should make the indole NH more acidic. 相似文献
17.
Dienamine and Friedel–Crafts One‐Pot Synthesis,and Antitumor Evaluation of Diheteroarylalkanals
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María Frías Dr. José M. Padrón Dr. José Alemán 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(22):8237-8241
An asymmetric synthesis of diheteroarylalkanals through one‐pot dienamine and Friedel–Crafts reaction is presented. The reaction tolerates a large variety of substituents at different positions of the starting aldehyde and also in the indole nucleophile, and a range of diheterocyclic alkanals can be achieved. Furthermore, we have studied the antiproliferative activity of these new compounds in representative cancer tumor cell lines. 相似文献
18.
Abstract— Porphyrins appended in the meso positions with 1,2-diazole, indole and quinoline are shown to exhibit enhanced fluorescence quantum yields relative to meso tetraphenyl porphyrin. The singlet emission yields decrease with the number of appended heterocyclic bases. An intramolecular charge transfer resonance mechanism has been advanced to interpret these results. 相似文献
19.
Eiko Yasui 《Tetrahedron》2009,65(2):461-1232
Aryl hydrazones, the precursor of Fischer indole synthesis, were easily obtained by nucleophilic addition of aryllithium reagents to diazo esters. The aryl hydrazones were converted into indoles in good yields by heating with thionyl chloride in alcohol. Grignard reagent was also a good nucleophile, whereas organozinc reagent did not react with diazo esters. Aryllithium reagents were prepared by reacting aryl bromides having various substitutions at 2-, 3-, 4-, or multi positions with n-BuLi. The addition of nucleophiles derived from bromopyridines to diazo esters also gave hydrazones. 相似文献
20.
S. A. Maklakov Yu. I. Smushkevich I. V. Magedov 《Chemistry of Heterocyclic Compounds》2002,38(8):904-907
A method was developed for the production of indole compounds containing an amino group at positions 4 and 6 of the benzene ring on the basis of the indolization of the 3-acetylaminophenylhydrazone of ethyl levulinate. A series of derivatives of 2-(4-amino-2-methyl-1H-indol-3-yl)- and 2-(6-amino-2-methyl-1H-indol-3-yl)acetic acids at the 4- and 6-amino group were synthesized. 相似文献