共查询到20条相似文献,搜索用时 15 毫秒
1.
Conjugate addition of indoles and thiols with a variety of electron-deficient olefins mediated by a catalytic amount of Bi(OTf)3 at ambient temperature to afford the corresponding Michael adducts in good to excellent yields with high selectivity is reported. 相似文献
2.
Madabhushi Sridhar Mallu Kishore Kumar ReddyVangipuram Venkata Sairam Jillella RaveendraKondal Reddy Godala Chinthala NarsaiahBeeram China Ramanaiah Cirandur Suresh Reddy 《Tetrahedron letters》2012,53(27):3421-3424
An efficient method for the preparation of nitriles directly from aldehydes by reaction with AHA using Bi(OTf)3 as the catalyst is described. Bi(OTf)3 is shown to be an efficient catalyst also for the conversion of aldoximes into nitriles. 相似文献
3.
Kumkum KumariDushyant Singh Raghuvanshi Viatcheslav JouikovKrishna Nand Singh 《Tetrahedron letters》2012,53(9):1130-1133
An efficient, rapid, and green synthesis of functionalized pyrazoles has been accomplished under solvent-free conditions by the reaction of phenyl hydrazine, aldehydes and ethyl acetoacetate. This approach exploits the synthetic potential of microwave irradiation and scandium triflate combination and offers many advantages such as excellent product yields, shorter reaction time, easy isolation of products, and environmentally benign reaction conditions. 相似文献
4.
T. Srikanth Reddy 《Tetrahedron letters》2006,47(38):6825-6829
A wide variety of alcohols, phenols and amines are efficiently and selectively converted into the corresponding acetates by treatment with acetic anhydride in the presence of catalytic amounts of La(NO3)3·6H2O under solvent-free conditions at room temperature. The method is compatible with acid sensitive hydroxyl protecting groups such as TBDMS, THP, OBz, OBn, Boc and some isopropylidenes and offers excellent yields of the mono acetates of 1,3-, 1,4- and 1,5-diols. 相似文献
5.
6.
Facile Yb(OTf)3 promoted one-pot synthesis of polyhydroquinoline derivatives through Hantzsch reaction 总被引:1,自引:0,他引:1
Yb(OTf)3 catalyzed efficient Hantzsch reaction via four-component coupling reactions of aldehydes, dimedone, ethyl acetoacetate and ammonium acetate at ambient temperature was described as the preparation of polyhydroquinoline derivatives. The process presented here is operationally simple, environmentally benign and has excellent yield. Furthermore, the catalyst can be recovered conveniently and reused efficiently. 相似文献
7.
在离子液体BMImPF6中, 用不同的钯催化剂和Lewis酸三氟甲磺酸铜Cu(OTf)2共催化苯乙烯二聚反应, 发现用Pd(OAc)2/Cu(OTf)2作催化剂, Pd/Cu物质的量之比为1~4时, 可高产率高选择性地获得苯乙烯二聚产物1,3-二苯基-1-丁烯. BMImPF6对催化剂有较好的溶解性, 可固定催化剂体系, 使催化剂有效地与产品分离. 同时, α-甲基苯乙烯的二聚反应表明, 室温下不发生反应, 提高温度有利于反应进行. 相似文献
8.
Salvatore GenoveseFrancesco Epifano Maria Carla MarcotullioCaroline Pelucchini Massimo Curini 《Tetrahedron letters》2011,52(27):3474-3477
Quinolines have been synthesized in very good yields from 2-aminoarylketones and differently substituted carbonyl compounds in the presence of Yb(OTf)3 as the catalyst. The method is applicable to both cyclic and acyclic carbonyl compounds with only slight differences in the experimental procedure. 相似文献
9.
Maryam YadegariMajid Moghadam Shahram TangestaninejadValiollah Mirkhani Iraj Mohammadpoor-Baltork 《Polyhedron》2012,31(1):332-338
In the present work, highly efficient trimethylsilylation of alcohols and phenols with hexamethyldisilazane (HMDS) catalyzed by high-valent [TiIV(salophen)(OTf)2] is reported. Under these conditions, primary, secondary and tertiary alcohols as well as phenols were silylated in short reaction times and high yields. It is noteworthy that this method can be used for chemoselective silylation of primary alcohols in the presence of secondary and tertiary alcohols and phenols. The catalyst was reused several times without loss of its catalytic activity. 相似文献
10.
Wei-Chieh YangXin-An Lu Suvarn S KulkarniShang-Cheng Hung 《Tetrahedron letters》2003,44(42):7837-7840
A triethylsilane-reductive etherification of the trimethylsilyl ethers with a variety of carbonyl compounds in good yields at room temperature employing 0.5 mol% Cu(OTf)2 as an extremely efficient catalyst is described here. 相似文献
11.
Rina Ghosh Swarupananda Maiti Arijit Chakraborty Dilip K. Maiti 《Journal of molecular catalysis. A, Chemical》2004,210(1-2):53-57
A new efficient one-pot synthesis of α-amino phosphonates derived from nitro substituted anilines, aldehydes and diethyl phosphite has been carried out by employing 5 mol% of In(OTf)3. The method is equally effective for the generation of α-amino phosphonates from various carbonyl compounds and other amines. 相似文献
12.
1,2,3,5-Tetrasubstituted pyridinium amino acid isodesmosine is a crosslinking amino acid of elastin and is an attractive biomarker for the diagnosis of chronic obstructive pulmonary disease (COPD). Herein, we report an application of the Chichibabin pyridine synthesis to the total synthesis of isodesmosine. Specifically, the appropriate protected lysine and the corresponding aldehyde were reacted using Pr(OTf)3 in H2O/MeOH. 相似文献
13.
An effective, convenient, and mild coupling reaction of benzylic alcohols with terminal alkynes has been developed. As an effective Lewis acid, Cu(OTf)2-catalyzed arylmethylation of terminal alkynes with benzylic alcohols generated the corresponding products in BrCH2CH2Br with good yields in the absence of ligand, base, and additive. 相似文献
14.
Conjugate addition of indoles to α,β-unsaturated ketones using Cu(OTf)2 immobilized in ionic liquids
Indoles undergo smooth conjugate addition with α,β-unsaturated ketones in the presence of 10 mol% copper(II) triflate immobilized in air and moisture stable [bmim]BF4 ionic liquid under mild conditions to afford the corresponding conjugate addition products in high to quantitative yields. The recovery of Cu(OTf)2 is facilitated by the ionic liquid. The recovered catalyst was reused four to five times with consistent activity. 相似文献
15.
A mild and facile method for the synthesis of 3-arylbenzo[f]quinoline-1,2-dicarboxylate derivatives is reported by an imino-Diels-Alder reaction in high yields (76-92%). This procedure includes a novel three-component reaction of aromatic aldehyde, naphthalen-2-amine, and but-2-ynedioate catalyzed by Yb(OTf)3 in toluene. The results are obviously different from those of the simple substituted aniline-involved reactions catalyzed by ZnCl2 or KOH in the literature. 相似文献
16.
Noor-ul H. Khan Santosh Agrawal Sayed H.R. Abdi Eringathodi Suresh 《Tetrahedron letters》2008,49(4):640-644
The synthesis of α-aminonitriles of ketones and aldehydes was performed in very short reaction times (20 min) with excellent yields in the presence of 5 mol % of Fe(Cp)2PF6 under solvent-free conditions. 相似文献
17.
N. Suryakiran 《Tetrahedron letters》2006,47(46):8039-8042
Facile N-tert-butoxycarbonylation of amines is described by the treatment of various primary, secondary, benzylic and aryl amines with di-tert-butyl dicarbonate in the presence of catalytic amounts of La(NO3)3·6H2O under solvent-free conditions at room temperature to afford N-tert-butylcarbamates in excellent yields. 相似文献
18.
The electrochemistry and electrochemiluminescence (ECL) of novel three-dimensional nanostructured Ru(bpy)32+/Ni(OH)2 microspheres were investigated for the first time. The negatively charged porous Ni(OH)2 microspheres composed of Ni(OH)2 nanowires were specifically designed to interact with Ru(bpy)32+. The large surface area and porous structure of Ni(OH)2 microspheres enhance loading of Ru(bpy)32+ and mass transport of the model analyte, tripropylamine (TPA). Excellent ECL performance of the presented sensor was achieved including good stability and wide linear range from 7.7 × 10−10 to 3.8 × 10−3 M with the detection limit of 2.6 × 10−10 M to TPA. 相似文献
19.
Akkirala Venkat Narsaiah 《Journal of organometallic chemistry》2007,692(17):3614-3618
A variety of hydroxy functional groups was protected as their corresponding trimethylsilyl ethers using HMDS in the presence of lanthanum trichloride. The catalyst LaCl3 activates the HMDS and accelerates the reaction under mild reaction conditions at room temperature to afford the corresponding silylated products in excellent yields. 相似文献
20.
Xuean Chen Fangping Song Xinan Chang Hegui Zang Weiqiang Xiao 《Journal of solid state chemistry》2009,182(11):3091-3097
Two oxoborates, (Pb3O)2(BO3)2MO4 (M=Cr, Mo), have been prepared by solid-state reactions below 700 °C. Single-crystal XRD analyses showed that the Cr compound crystallizes in the orthorhombic group Pnma with a=6.4160(13) Å, b=11.635(2) Å, c=18.164(4) Å, Z=4 and the Mo analog in the group Cmcm with a=18.446(4) Å, b=6.3557(13) Å, c=11.657(2) Å, Z=4. Both compounds are characterized by one-dimensional chains formed by corner-sharing OPb4 tetrahedra. BO3 and CrO4 (MoO4) groups are located around the chains to hold them together via Pb–O bonds. The IR spectra further confirmed the presence of BO3 groups in both structures and UV–vis diffuse reflectance spectra showed band gaps of about 1.8 and 2.9 eV for the Cr and Mo compounds, respectively. Band structure calculations indicated that (Pb3O)2(BO3)2MoO4 is a direct semiconductor with the calculated energy gap of about 2.4 eV. 相似文献