共查询到20条相似文献,搜索用时 31 毫秒
1.
Richard C. Effland Beth Ann Gardner Joseph Strupczewski 《Journal of heterocyclic chemistry》1981,18(4):811-814
The synthesis of 2,3-dihydrospiro[benzofuran-2,4′-piperidines] 3 and 2,3-dihydrospiro[benzofuran-2,3′]-pyrrolidine] 6 is described. The synthesis was achieved by a Grignard reaction of a 2-fluorobenzylhalide with an appropriate cycloazaalkyl ketone to yield the tertiary alcohols 1 and 4 . Subsequent intramolecular displacement of the aromatic fluoride by the derived alkoxides provided the novel system. Nitration of 1′-acetyl-2,3-dihydrospiro[benzofuran-2,4′-piperidine] 7 resulted in a 5-nitro derivative. 相似文献
2.
Carlo Dell'Erba Giuseppe Guanti Giacomo Garbarino 《Journal of heterocyclic chemistry》1974,11(6):1017-1021
The nitration of 2,3′-bithienyl ( 1 ) with fuming nitric acid in acetic anhydride at 0° gives a mixture of 3-nitro- ( 2 ), 2′ -nitro- ( 3 ) and 5-nitro-2,3′-bithienyl ( 4 ) with relative percentages of 38.7%, 34.8% and 26.5%. When the nitration of 1 was carried out with fuming nitric acid in acetic acid at 20°, the same compounds 2, 3 and 4 were obtained, but with different relative percentages: 20.4%, 36.5% and 43.1% respectively. The results of the mononitration of 1 are compared with those obtained in other electrophilic substitutions and with the theoretical predictions. The further nitrations of 2, 3 and 4 with nitric acid in acetic anhydride at room temperature lead to the formation of five dinitro-2,3′-bithienyl isomers. Compound 2 gives a mixture of 2′,3-dinitro- ( 5 ) and 3,5′-dinitro-2,3′-bithienyl ( 6 ); compound 3 gives a mixture of 5 , 2′,5-dinitro- ( 7 ) and 2′,4-dinitro-2,3′-bithienyl ( 8 ); compound 4 gives 7 and 5,5′-dinitro-2,3′-bithienyl ( 9 ). The possible reasons of the formation of the various dinitro-2,3′-bithienyl isomers are discussed. 相似文献
3.
An intramolecular, organocatalyzed Michael addition has been developed to obtain biologically important 2,3‐disubstituted cis‐2,3‐dihydrobenzofurans. By using mandelic acid salts of primary aminocatalysts, derived from cinchona alkaloids, the intramolecular cyclization reaction has been developed to proceed in high yield, with moderate to good diastereoselectivity, and up to 99 % ee. Based on the absolute configuration of the formed 2,3‐disubstituted‐cis‐2,3‐dihydrobenzofurans and by considering the observed substrate scope restrictions, a mechanistic rationalization has been presented. 相似文献
4.
M. M. Lipunov E. A. Kaigorodova L. D. Konyushkin S. I. Firgang G. D. Krapivin 《Chemistry of Heterocyclic Compounds》2007,43(9):1189-1196
It has been established that the interaction of N1-(2-hydroxyphenylmethylthieno[2,3-b]pyrid-3-yl)arylamides with hydrazine hydrate leads to thieno[2,3-b]pyridine-2,3-diamines.
It was shown that the reaction of the latter with acetylacetone and acetoacetic ester occurs regioselectively at the amino
group in position 3 of the thiophene ring.
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Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1400–1408, September, 2007. 相似文献
5.
Hassan Allouchi Georges Bravic Nacer Lahrahar Jean‐Pierre Desvergne Henri Bouas‐Laurent 《Acta Crystallographica. Section C, Structural Chemistry》2008,64(11):o620-o622
Anthraquinone derivatives form an important class of dyes and are also known for their medicinal properties. Recently, 2,3‐disubstituted anthraquinones have been shown unexpectedly to jellify various organic solvents. No information on the packing mode of these derivatives was known. Here, the first X‐ray structure of a 2,3‐disubstituted anthraquinone is reported, namely 2,3‐diethoxy‐9,10‐anthraquinone, C18H16O4. The merit of this study lies in the observation of significant differences between the packing in 9,10‐anthraquinone, which displays a herring‐bone arrangement, and that in the title 2,3‐diethoxy derivative, in which the molecules lie on parallel crystallographic morror planes separated by a distance of 3.4081 (1) Å, reminiscent of the graphite layer architecture. 相似文献
6.
O. A. Sof''ina N. M. Igidov E. N. Koz''minykh N. N. Trapeznikova Yu. S. Kasatkina V. O. Koz''minykh 《Russian Journal of Organic Chemistry》2001,37(7):1017-1025
Acylpyruvic acids readily react with 2,3-diaminopyridine to form (Z)-3-acylmethylene-1H-3,4-di- hydropyrido[2,3-b]pyrazin-2-ones. 5-Aryl-2,3-dihydrofuran-2,3-diones which can be regarded as lactones derived from -enolized aroylpyruvic acids react with 2,3-diaminopyridine under mild conditions, yielding regioisomeric (Z)-2-aroylmethylene-4H-1,2-dihydropyrido[2,3-b]pyrazin-3-ones. The structure of the products and reaction chemoselectivity are discussed. 相似文献
7.
Hyun‐A Chung Jeum‐Jong Kim Su‐Dong Cho Sang‐Gyeong Lee Yong‐Jin Yoon Sung‐Kyu Kim 《Journal of heterocyclic chemistry》2002,39(4):685-689
Reaction of chloropyridazin‐3‐one 1, 5 and 10 with catechol in the presence of potassium carbonate gave the corresponding [1,4]benzodioxino[2,3‐e and/or 2,3‐d]pyridazinones 2, 7, 8 and 11 . 相似文献
8.
Richard J. Sundberg Bradley C. Pearce Joseph P. Laurino 《Journal of heterocyclic chemistry》1986,23(2):537-539
Authentic pyrrolidine-2,3-dione has been prepared by two different routes. It is shown that the material previously reported is actually a hydrolysis product, 4-amino-2-oxobutyric acid. 1-Allyl- and 1-ethoxypyrroli-dine-2,3-dione have been prepared as N-protected pyrrolidine-2,3-diones potentially useful in synthesis. 相似文献
9.
Anna C. Doner Matthew M. Davis Alanna L. Koritzke Matthew G. Christianson Justin M. Turney Henry F. Schaefer Leonid Sheps David L. Osborn Craig A. Taatjes Brandon Rotavera 《国际化学动力学杂志》2021,53(1):127-145
Oxiranes are a class of cyclic ethers formed in abundance during low‐temperature combustion of hydrocarbons and biofuels, either via chain‐propagating steps that occur from unimolecular decomposition of β‐hydroperoxyalkyl radicals (β‐?QOOH) or from reactions of H?O with alkenes. The cis‐ and trans‐isomers of 2,3‐dimethyloxirane are intermediates of n‐butane oxidation, and while rate coefficients for β‐?QOOH → 2,3‐dimethyloxirane + ?OH are reported extensively, subsequent reaction mechanisms of the cyclic ethers are not. As a result, chemical kinetics mechanisms commonly adopt simplified chemistry to describe the consumption of 2,3‐dimethyloxirane by convoluting several elementary reactions into a single step, which may introduce mechanism truncation error—uncertainty derived from missing or incomplete chemistry. The present research examines the isomer dependence of 2,3‐dimethyloxirane reaction mechanisms in support of ongoing efforts to minimize mechanism truncation error. Reaction mechanisms are inferred via the detection of products from Cl‐initiated oxidation of both cis‐2,3‐dimethyloxirane and trans‐2,3‐dimethyloxirane using multiplexed photoionization mass spectrometry (MPIMS). The experiments were conducted at 10 Torr and temperatures of 650 K and 800 K. To complement the experiments, the enthalpies of stationary points on the ?R + O2 surfaces were computed at the ccCA‐PS3 level of theory. In total, 28 barrier heights were computed on the 2,3‐dimethyloxiranylperoxy surfaces. Two notable aspects are low‐lying pathways that form resonance‐stabilized ketohydroperoxide‐type radicals caused by ?QOOH ring‐opening when the unpaired electron is localized adjacent to the ether group, and cis‐trans isomerization of ?R and ?QOOH radicals, via inversion, which enable reaction pathways otherwise restricted by stereochemistry. Several species were identified in the MPIMS experiments from ring opening of 2,3‐dimethyloxiranyl radicals. Neither of the two conjugate alkene isomers prototypical of ?R + O2 reactions were detected. Products were also identified from decomposition of ketohydroperoxide‐type radicals. The present work provides the first analysis of 2,3‐dimethyloxirane oxidation chemistry and reveals that consumption pathways are complex and require the expansion of submechanisms in chemical kinetics mechanisms. 相似文献
10.
M. A. Del Valle E. T. Silva F. R. Diaz M. E. Bodini L. Gargallo 《Journal of polymer science. Part A, Polymer chemistry》2000,38(9):1698-1703
The optima conditions to electrosynthesize poly(2,3‐diaminophenol) by electro‐oxidation of the monomer were determined, and the electrodeposits obtained characterized by electrochemical methods, UV‐vis, FTIR, conductivity and viscosity measurements. The influence of parameters such as electrolytical medium and electrochemical conditions on the electro‐oxidation of 2,3‐diaminophenol were also investigated. It has been established that appropriate deposits are obtained only when very anhydrous acetonitrile is used as solvent. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 1698–1703, 2000 相似文献
11.
Kazuko Shirai Koushi Fukunishi Dongfeng Hou Masaru Matsuoka 《Journal of heterocyclic chemistry》2000,37(5):1299-1304
Previously synthesized 2‐(3′‐chloro‐5′,6′‐dicyanopyrazin‐2′‐yl)cyclopentan‐1‐one 1 , obtained from the reaction of 2,3‐dichloro‐5,6‐dicyanopyrazine with 1‐pyrrolidino‐1‐cyclopentene, was further reacted with primary alkylamines to give mixtures of diastereomer of 5‐alkyl‐2,3‐dicyano‐5a,8a‐dihy‐dro‐5a‐hydroxycyclopentano[1′,2′:4,5]pyrrolo[2,3‐b]pyrazines 3a‐h in high yield. The reaction of 2‐alkylamino‐3‐chloro‐5,6‐dicyanopyrazine with 1‐pyrrolidino‐1‐cyclohexene gave 5‐alkyl‐2,3‐dicyanocyclopentano[1′,2′:4,5]pyrrolo[2,3‐b]pyrazines 5a‐b together with 5‐alkylamino‐2,3‐dicyano‐6‐pyrrolidinopyrazines 6a‐b . The products prepared are all of interest as potential pesticides and new fluorescent chromophores. 相似文献
12.
Anodic oxidation of 2-nitropropane in a methanol solution of sodium iodide and hydroxide is found to produce 2,3-dimethyl-2,3-dinitrobutane
with a yield of 65-70% under optimum conditions.
Deceased. 相似文献
13.
Exploration of the Photodegradation of Naphtho[2,3‐g] quinoxalines and Pyrazino[2,3‐b]phenazines 下载免费PDF全文
Dr. Nicole Kolmer‐Anderl Dr. Andreas Kolmer Prof. Dr. Christina M. Thiele Prof. Dr. Matthias Rehahn 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(15):5277-5287
Nitrogen‐containing polycyclic aromatic hydrocarbons are very attractive compounds for organic electronics applications. Their low‐lying LUMO energies points towards a potential use as n‐type semiconductors. Furthermore, they are expected to be more stable under ambient conditions, which is very important for the formation of semiconducting films, where materials with high purity are needed. In this study, the syntheses of naphtho[2,3‐g]quinoxalines and pyrazino[2,3‐b]phenazines is presented by using reaction conditions, that provide the desired products in high yields, high purity and without time‐consuming purification steps. The HOMO and LUMO energies of the compounds are investigated by cyclic voltammetry and UV/Vis spectroscopy and their dependency on the nitrogen content and the terminal substituents are examined. The photostability and the degradation pathways of the naphtho[2,3‐g]quinoxalines and pyrazino[2,3‐b]phenazines are explored by NMR spectroscopy of irradiated samples affirming the large influence of the nitrogen atoms in the acene core on the degradation process during the irradiation. Finally, by identifying the degradations products of 2,3‐dimethylnaphtho[2,3‐g]quinoxaline it is possible to track down the most reactive position in the compound and, by blocking this position with nitrogen, to strongly increase the photostability. 相似文献
14.
Hsiencheng Shih Renshuay J. Shih Dennis A. Carson 《Journal of heterocyclic chemistry》2011,48(6):1243-1250
2,3‐Diaryl‐substituted maleic anhydrides were prepared by a modified one‐pot synthesis of Perkin condensation using mixed sodium salts of arylglyoxylic acid and arylacetic acid with acetic anhydride in 1,4‐dioxane. The treatment of these anhydrides with ammonium bicarbonate, or methanolic hydrazine, offered the corresponding 2,3‐diaryl‐substituted maleimides and maleic hydrazides (4,5‐diaryl‐substituted 1,2‐dihydropyridazine‐3,6‐dione), respectively. Evidence obtained from NMR, UV, and mass spectra suggest that 2,3‐diaryl‐substituted maleic hydrazides do not exhibit monolactim forms. Ring contraction of the diaryl‐substituted maleic hydrazide by nitrosation led to the formation of the corresponding maleimide. Interconversion between the corresponding maleic hydrazide and maleimide was observed following equilibrium reaction. Our experiment proposes that the chemistry of 2,3‐diaryl‐substituted maleic hydrazides rarely involves the function of ethylene moiety and resembles that of succinic hydrazine. J. Heterocyclic Chem.,(2011). 相似文献
15.
2,3-Diaryl-1,4-diazolyl-2,3-epoxybutanes have been prepared from dimethylstilbenes. An efficient although neglected synthesis of the required olefins has been recovered from the literature. The target compounds show moderate antifungal activity. 相似文献
16.
Alaa A. Hassan Nasr K. Mohamed Lamiaa E. Abd El‐Haleem Stefan Bräse Martin Nieger 《中国化学》2016,34(8):814-822
A one step synthesis protocol for the conversion of heteroylthiosemicarbazides and 2,3‐dichloro‐1,4‐naphthoquinone to naphtho[2,3‐d]thiazoles, naphtho[2,3‐e][1,3,4]thiadiazines as well as bis(naphtho[2,3‐d]thiazolyl)copper(II) derivatives is described. The products were conclusively confirmed by single crystal X‐ray analyses. A mechanism for the formation of the products is presented. 相似文献
17.
I. V. Krylova D. D. Nekrasov Yu. S. Andreichikov 《Chemistry of Heterocyclic Compounds》1988,24(11):1204-1206
The reaction of 5-aryl-2,3-dihydrofuran-2,3-diones with benzamide oxime, diaminoglyoxime, and hydroxyurea gave 3-phenyl-5-aroylacetyl-1,2,4-oxadiazoles, 5,6-dihydroxyimino-3-phenacylidenepiperazin-2-ones, and 3-hydroxy-5-phenacylideneimidazolidine-2,4-diones, respectively. 6-Phenacylidene-5-oxo-4,5,6,7-tetrahydrofurazano [3,4-b]pyrazines are formed in the reaction of 5-aryl-2,3-dihydrofuran-2,3-diones with diaminofurazan.For Communication 7, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1457–1460, November, 1988. 相似文献
18.
S. A. Yamashkin E. A. Oreshkina N. V. Zhukova 《Chemistry of Heterocyclic Compounds》2007,43(8):1044-1051
A study was carried out on the reactions of 4-amino-2,3-dimethyl-and 4-amino-1,2,3-trimethylindoles with acetylacetone, dibenzoylmethane,
ethyl acetoacetate, ethyl trifluoroacetoacetate, and ethyl oxaloacetate. Methods were developed for the synthesis of a series
of substituted pyrrolo-[2,3-h]quinolines.
__________
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1234–1242, August, 2007. 相似文献
19.
Seiji Yamaguchi Toshiharu Katsuki Hajime Yokoyama Yoshiro Hirai 《Journal of heterocyclic chemistry》2001,38(2):511-514
Some 2‐isopropenyl‐2,3‐dihydronaphtho[2,3‐b]furan‐4,9‐diones la‐f,b',f were prepared by one‐step cyclizations of 2‐hydroxy‐1,4‐naphthoquinones 2a‐f with 1,4‐dibromo‐2‐methyl‐2‐butene ( 3 ). 相似文献
20.
B. Zh. Elmuradov Kh. A. Bozorov Kh. M. Shakhidoyatov 《Chemistry of Heterocyclic Compounds》2011,46(11):1393-1399
2,3-Dimethyl- and 2,3-tri-, 2,3-tetra-, and 2,3-pentamethylene-substituted 8-arylidene-6,7-dihydro-pyrrolo[1,2-a]thieno[2,3-d]pyrimidin-4-ones were synthesized by the reaction of 2,3-dimethyl- and 2,3-tri-, 2,3-tetra-, and 2,3-pentamethylene-7,8-dihydropyrrolo[1,2-a]thieno[2,3-d]pyrimidin-4(6H)-ones with benzaldehyde, its 4-dimethylamino-, 3,4-dimethoxy-, and 3,4-methylenedioxy derivatives and also
furfural in the presence of NaOH. 相似文献