共查询到20条相似文献,搜索用时 15 毫秒
1.
Li W Nelson DP Jensen MS Hoerrner RS Javadi GJ Cai D Larsen RD 《Organic letters》2003,5(25):4835-4837
Imidazo[1,2-a]pyrimidine can be arylated at the 3-position with aryl bromides in the presence of base and a catalytic amount of palladium. This provides an efficient one-step synthesis of 3-arylimidazo[1,2-a]pyrimidines from the unsubstituted heterocycle. [reaction: see text] 相似文献
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An effective, regioselective C-2 arylation of imidazo[2,1-b]thiazoles catalyzed by Cu(I) has been developed. This arylation proceeded smoothly without promotion of the ligands, and various functional (22 samples) groups were well tolerated. Preliminary mechanistic studies of this arylation are also reported. 相似文献
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Leung-Toung R Tam TF Zhao Y Simpson CD Li W Desilets D Karimian K 《The Journal of organic chemistry》2005,70(16):6230-6241
A versatile synthetic route to potentially useful fused-ring [1,2,4]thiadiazole scaffolds (e.g., 7a and 10b) via exchange reactions of the precursor [1,2,4]thiadiazol-3-(2H)one derivatives (e.g., 6 and 9) with appropriately substituted nitriles (e.g., cyanogen bromide or p-toluenesulfonyl cyanide) under mild conditions is described. For example, the tricyclic 3-bromo [1,2,4]THD derivative (7a) underwent S(N)Ar substitution with a variety of nucleophiles, which included amines, malonate esters and alcohols. Likewise, the bicyclic 3-p-tosyl [1,2,4]THD (10b) was employed as a template in reaction with diamines, and the resulting substituted diamines (e.g., 12a or 12e) were further selectively derivatized at the N1 and/or N2 positions in a linear fashion. The X-ray crystal structure of the 3-methyl bicyclic [1,2,4]THD (21) was obtained, and selective methylation at the N1 position via a protection-alkylation-deprotection protocol, as illustrated in Scheme 6, was confirmed. Alternatively, a short convergent synthesis of N1-functionalized derivatives from the reaction of 10b with appropriately substituted secondary amines was also developed. Hence, these synthetic strategies were advantageously exploited to provide access to a variety of diversely derivatized 3-substituted fused-ring [1,2,4]thiadiazole derivatives. 相似文献
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Hydrazonoyl bromides 1a-c react with 5-amino-3-phenyl-1H-pyrazole, 5-amino-1H-1,2,4-triazole, 2-aminopyridine, and 2-aminobenzimidazole to afford the corresponding imidazol[1,2-b]pyrazoles 10, imidazo[1,2-b]-1,2,4-triazoles 11, imidazo[1,2-a]pyridines 16, imidazo[1,2-a]pyrimidines 17, and imidazo[1,2-a]benzimidazoles 20, respectively. Compounds 1a-c reacted also with 2-methylthiobenzimidazole to give 1,2,4-triazolo[4,3-a]benzimidazole derivatives 21. © 1997 John Wiley & Sons, Inc. 相似文献
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Ivanov S. M. Tuzharov Е. I. Kolotyrkina N. G. 《Russian Journal of General Chemistry》2021,91(12):2453-2461
Russian Journal of General Chemistry - Alkylation of tert-butyl-7-amino-3-tert-butyl-8-R1-2-oxo-1,2-dihydropyrrolo[1,2-b][1,2,4]triazin-6-carboxylates with alkyl halides R2Br (R1 = CN, CO2Et; R2 =... 相似文献
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Dmitry B. Vinogradov Alexei N. Izmest'ev Angelina N. Kravchenko Natalya G. Kolotyrkina Galina A. Gazieva 《Journal of heterocyclic chemistry》2024,61(1):137-145
A method for the regioselective synthesis of imidazo[4,5-e][1,3]thiazino[2,3-c][1,2,4]triazine derivatives has been developed by the reaction of imidazotriazinethiones with ethyl phenylpropiolate upon treatment with potassium carbonate or sodium methoxide in methanol. The synthesis was accomplished by Michael-type addition of the imidazotriazinethiones to the triple bond of ethyl phenylpropiolate followed by subsequent intramolecular cyclization. 相似文献
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Ranjana Aggarwal Shilpa Sharma Mona Hooda Dionisia Sanz Rosa M. Claramunt Brendan Twamley Isabel Rozas 《Tetrahedron》2019,75(50):130728
The first visible-light mediated, simple, efficient and ecofriendly protocol for the regioselective synthesis of novel [1,2,4]triazolo[3,4-b][1,3,4]thiadiazines has been developed by the reaction of α-bromodiketones, generated in situ by the bromination of a diverse array of β-diketones with N-bromosuccinimide, with 4-amino-[1,2,4]triazole-3-thiols. The methodology does not require the presence of any additives and this reaction proceeded in the presence of EDG (OMe), EWG (Cl) and heteroarenes (thiophenyl) giving the expected products in good to excellent yields. A solvent free protocol was also established to accomplish the synthesis of target compounds but it required PTSA as a catalyst and yields are comparatively poor. The structure of the regioisomer has been confirmed unambiguously by heteronuclear 2D-NMR [(1H-13C) HMBC, (1H-15N) HMBC, (1H-13C) HMQC] spectroscopic and X-ray crystallographic studies. 相似文献
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Russian Journal of Organic Chemistry - 相似文献
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3-Substituted imidazo[1,2-a]pyridines, imidazo[1,2-a]pyrimidines, and imidazo[1,2-c]pyrimidine were obtained regiospecifically in yields of 35-92% in one pot by reaction of 2-aminopyridines or 2-(or 4-)aminopyrimidines, respectively, with 1,2-bis(benzotriazolyl)-1,2-(dialkylamino)ethanes. 相似文献
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Hedieh Pilali Shirin Faraji Kamazani Shahram Moradi Setareh Moghimi Mohammad Mahdavi Loghman Firoozpour 《合成通讯》2016,46(6):563-567
A novel three-step sequence toward benzo[e]imidazo[1,2-c][1,2,3]triazine derivatives is investigated. This pathway started from commercially available starting materials afforded 5a–h in good to excellent yields. In this method, we took the advantage of diazonium chemistry, which was followed by intramolecular N-N bond formation in the construction of N-rich cycles. 相似文献
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Novel highly functionalized benzimidazoles were synthesized in two steps by microwave irradiation: construction of the benzimidazole ring followed by ring closure to the new tricyclic system. 相似文献
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V. P. Kruglenko A. A. Timoshin N. A. Klyuev E. V. Logachev M. V. Povstyanoi 《Chemistry of Heterocyclic Compounds》1986,22(7):791-795
When boiled with phosphorus pentachloride in phosphorus oxychloride, 2-methyl-6-phenyl-imidazo[1,2-b]1,2,4-triazin-4H-3-one gives a mixture of mono- and dichloro derivatives, whereas the action of thionyl chloride in chloroform with a catalytic amount of DMFA gives only the monosubstituted product 2-methyl-3-chloro-6-phenylimidazo[1,2-b]-1,2,4-triazine. The reactivity of the 3-chloro derivatives of imidazo[1,2-b]-1,2,4-triazine in reactions with diethylamine, piperidine, morpholine, aniline, hydrazine hydrate and thiourea was investigated.For Communication 13, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 981–985, July, 1986. 相似文献