共查询到20条相似文献,搜索用时 375 毫秒
1.
Natthawut Toworakajohnkun Mongkol Sukwattanasinitt Paitoon Rashatasakhon 《Tetrahedron letters》2017,58(43):4149-4152
A new synthetic method for triazatruxenes from indoles is developed using N-bromosuccinimide (NBS) as a user-friendly reagent. Major reaction parameters including the amount of NBS, substrate concentration, temperature, addition rate and addition method are investigated. Additional experiments are also conducted in order to gain access toward the reaction mechanism. Compared to the use of Br2 in the conventional method, this reaction requires less reaction time, provides better yields, and displays excellent reproducibility. The reaction can be conveniently performed at 10 g scale and it is also applicable to several substituted indoles, benzoindole, and N-alkyl indoles. 相似文献
2.
Jeffrey A Campbell Viola Bordunov Chris A Broka John Dankwardt Robert T Hendricks James M Kress Keith A.M Walker Jin-Hai Wang 《Tetrahedron letters》2004,45(19):3793-3796
The 3-arylmethylation of indoles using TMSOTf/Et3SiH with a wide variety of substituted benzaldehydes has been accomplished. Under these mild Lewis acid mediated reductive conditions, it was demonstrated that indoles bearing both 6-MeSO2 and 2-methyl substituents could be 3-arylmethylated in good to excellent yields to afford the corresponding 3-arylmethyl indoles, effective as selective COX-2 inhibitors. In addition, the viability of this method for the reductive alkylation of indoles by ketones was demonstrated and shown to be C-3 regioselective. For indoles bearing both a 6-MeSO2 and 2-cyano substituent where this indole reductive alkylation methodology was unsuccessful, an unprecedented Pd(0) mediated arylorganozinc coupling with the requisite substituted 3-methylcarbonatomethylindole proved successful in affording the desired 2-cyano-6-MeSO2-3-arylmethylindoles effective as selective COX-2 inhibitors. 相似文献
3.
K. Harsha Vardhan Reddy G. Satish K. Ramesh K. Karnakar Y.V.D. Nageswar 《Tetrahedron letters》2012,53(24):3061-3065
A new and elegant protocol for the synthesis of 1-substituted indoles was developed via aromatization of indoline/indoline carboxylic acid followed by C–N cross-coupling with various aryl halides in the presence of nano CuO as a recyclable catalyst, Cs2CO3 as a base in DMSO at 80 °C. 1-Substituted indoles were obtained in good to excellent yields and the catalytic system can be recycled up to four cycles without loss of catalytic activity. 相似文献
4.
The catalytic Friedel–Crafts alkylation of indoles with nitroalkenes to furnish 2-indolyl-1-nitroalkane derivatives at room temperature with moderate to excellent yields is reported using nanocrystalline titanium(IV) oxide (nano-TiO2) catalyst. In all cases, a single regioisomer was obtained. After completion of the reaction, the catalyst was recovered by centrifugation and activated under a nitrogen flow for 1 h at 250°C for further reuse. The nano-TiO2 can be reused for four cycles with a slight decrease of activity under the same reaction conditions. 相似文献
5.
Miwako Mori Katsutoshi Hori Masaya Akashi Masanori Hori Yoshihiro Sato Mayumi Nishida 《Angewandte Chemie (International ed. in English)》1998,37(5):636-637
Dry air is the source of molecular nitrogen for reactions with TiL4, Li, and TMSCl (L = Cl, OiPr; TMS = trimethylsilyl). The nitrogen–titanium complexes thus prepared can be used to synthesize indoles, pyrroles, and lactams from carbonyl compounds. Applying this method to 1 provides access to 2 , the key compound in the synthesis of (±)-lycopodine. 相似文献
6.
Taochun Zha Jiehui Rui Zhihan Zhang Dongqiang Zhang Zhirong Yang Peiyuan Yu Yingcheng Wang Fangzhi Peng Prof. Zhihui Shao 《Angewandte Chemie (International ed. in English)》2023,62(21):e202300844
Herein we report a Pd-catalyzed asymmetric allenylic alkylation strategy for the direct functionalization of 1H-indoles by employing P-chiral BIBOP-type ligands. The regioselectivity (N1/C3) of this process can be switched efficiently. Using Cs2CO3 at elevated temperatures in MeCN, N1-alkylated indoles bearing axial chirality with a stereocenter non-adjacent (β) to the nitrogen are produced in good yields with high enantioselectivity and complete N1-regioselectivity regardless of the electronic properties and substitution patterns of diverse indoles. Using K2CO3 at room temperature in CH2Cl2, chiral C3-alkylated indoles can also be obtained. Notably, we introduce a new class of tri-substituted allenylic electrophiles that proceeded through different pathways from di-substituted allenylic electrophiles. 相似文献
7.
Norberto Farfn J. Manuel Hernndez Pedro Joseph-Nathan Rosalinda Contreras 《Journal of heterocyclic chemistry》1990,27(6):1745-1749
Reaction of N-methylaniline with 40% glyoxal yields 1-methyl-2-(N-methyl-N-phenylglycyl)-3-(N-methylanilino)indole ( 1a ) as the main product together with 1-methyl-3-(N-methylanilino)indole ( 1b ). The reaction appears to be general for aromatic secondary amines since N-ethylaniline and N-phenylbenzylamine yield the corresponding indoles. The structure of 1a has been verified by single crystal X-ray diffraction. Compound 1a (C25H25N3O) crystallized in the triclinic space group Pl? with cell dimensions a = 10.085(3)Å, b = 10.371(3)Å, c = 11.908(5)Å, α = 74.2(3)°, β = 74.7(3)° and γ = 60.7(2)° with Z = 2. The complete 1H and 13C nmr assignment of indoles 1a and 1b was achieved from two-dimensional HETCOR and COSY spectra with the aid of homonuclear and heteronuclear double resonance experiments. 相似文献
8.
A new high‐yielding, operationally simple, solvent‐free, and mild method for preparation of pyrazolines, tetrahydrocarbazoles, and indoles has been developed using KHSO4 · H2O impregnated on SiO2. The reactions have been probed under microwave irradiation (MWI), and ultrasonic and thermal conditions, employing different solid supports. The data revealed that KHSO4 · H2O impregnated on SiO2 under MWI provides the best yields in a shorter time under solvent‐free reaction conditions. 相似文献
9.
Khalil Tabatabaeian Manouchehr Mamaghani Nosratollah Mahmoodi Alireza Khorshidi 《合成通讯》2013,43(11):1677-1684
Diastereoselective conjugate 1,4-addition of indoles to α,β-unsaturated carbonyl compounds (hormone steroids) using Ru(III) as catalyst is reported. It was found that RuCl3·nH2O catalyzes the Michael addition of indoles to hormone steroids, providing new 3-alkylated derivatives in good to excellent yields. 相似文献
10.
Summaryof main observation and conclusion A new and intriguing methodology to access various O-difluoromethylation oxime compounds from CICF2H,TBN and indoles is developed under mild reaction conditions.This strategy can suppress N-difluoromethylation of indoles successfully,in which there are two different active species(:CF2and·NO)while indoles are unprotected,featuringsimple operation and radical involvement. 相似文献
11.
A palladium-catalyzed one-pot procedure for the regioselective dimerization and cyanation of indoles
Ebrahim Kianmehr Mohammad Ghanbari Nasser Faghih Frank Rominger 《Tetrahedron letters》2012,53(15):1900-1904
A one-pot method for the regioselective dimerization and cyanation of indoles has been developed. The reaction uses safe and nontoxic K4[Fe(CN)6]·3H2O as the cyanating agent which introduces selectively a cyano group into the 3-position of biindoles with high efficiency. 相似文献
12.
Gangireddy Sujeevan Reddy Suresh Babu Nallapati P.S.V.K. Sri Saranya B. Sridhar Varadaraj Bhat Giliyaru Raghu Chandrashekhar Hariharapura G. Gautham Shenoy Manojit Pal 《Tetrahedron letters》2018,59(52):4587-4592
Propargylamine (secondary) has been explored as a building block in synthesizing indoles via an ultrasound assisted Pd/Cu-catalyzed coupling-cyclization method. Indoles containing a pyrazole moiety at C-2 attached via the –CH2NH– linker (designed as potential anti-tubercular agents) were synthesized first and then generality/scope of the methodology was expanded by synthesizing other indoles. Unexpected formation of imine side products in first cases helped in synthesizing related (pyrazole)imines via a Cu catalyzed ultrasound assisted aerobic oxidation of precursor amines. 相似文献
13.
A catalytic amount of scandium trifluoromethanesulfonate [Sc(OTf)3] (2.5 mol%) was used to catalyze the Michael addition of indoles to nitroolefins in water to afford the corresponding 3-alkylated indoles in good to excellent yields. The short reaction times, excellent yields, and renewability of the catalyst are noteworthy. 相似文献
14.
CrCl3·6H2O/hydrogenated bis‐Schiff base is found to be an effective catalyst system for synthesis of bis(indoly) methane via electrophilic addition reaction of indoles with aldehydes using acetonitrile as the solvent. The yields of isolated products are from good to excellent. 相似文献
15.
16.
An efficient and environmentally friendly protocol has been demonstrated for water-soluble (salicyladimine)2Cu complex-catalyzed Michael addition of indoles to nitroolefins in water at 30?°C. A variety of substituted indoles and β-nitrostyrenes could be worked well to provide the title products in 81–97% yields. Moreover, the catalyst can be reused directly at least for four times without significantly decreasing activity. 相似文献
17.
Mohit L. Deb Bhaskar Deka Prakash J. Saikia Pranjal K. Baruah 《Tetrahedron letters》2017,58(20):1999-2003
Here we report a base-catalyzed reaction of two different indoles with aldehydes under heating to produce unsymmetrical bis(indolyl)methanes (BIMs), in which one of the indole ring must be N-substituted. Mixture of EtOH-H2O is used as solvent. The reaction did not give symmetrical BIMs of N-substituted indoles or N–H indoles. However, traces of latter were formed in few cases, especially when electron-rich aldehydes were used. Diversely substituted indoles and aldehydes were used for the reaction. The reaction proceeds via 3-indolylalcohol, which we confirmed through isolation. The method also gives good yield on multigram scale reaction. 相似文献
18.
Mohammad M. Khodaei Parvin Ghanbary Iraj Mohammadpoor‐Baltork Hamid R. Memarian Ahmad R. Khosropour Kobra Nikoofar 《Journal of heterocyclic chemistry》2008,45(2):377-381
19.
A mild and efficient C(sp2)?H nitration of 3‐substituted indoles, by using the economical and non‐toxic cobalt nitrate hexahydrate [Co(NO3)2 ? 6 H2O] as a catalyst and tert‐butyl nitrite (TBN) as the nitro source, is reported. This approach provides a unique methodology involving a site‐selective C?N bond formation for preparation of C‐2 substituted nitro indoles. Utilization of the tBoc as the removable directing group enhances the synthetic utility of the method. 相似文献
20.
J. Jon Paul Selvam M. Srinivasulu N. Suryakiran V. Suresh S. Malla Reddy 《合成通讯》2013,43(11):1760-1767
A mild and efficient synthesis of bis(indolyl) methanes by the reaction of indoles with various aldehydes at room temperature in the presence of a catalytic amount of a La(NO3)3 · 6H2O afforded the corresponding bis(indolyl) methanes in excellent yields under solvent‐free conditions. 相似文献