共查询到20条相似文献,搜索用时 31 毫秒
1.
Mohammad Navid Soltani Rad Ali Khalafi-Nezhad Mohammad Ali Faghihi Abolfath Parhami 《Tetrahedron》2008,64(8):1778-1785
A convenient and efficient one-pot N-alkylation of nucleobases from alcohols using N-(p-toluenesulfonyl)imidazole (TsIm) is described. In this method, treatment of alcohols with a mixture of purine or pyrimidine nucleobase, TsIm, K2CO3, and triethylamine in refluxing DMF regioselectively furnishes the corresponding N-alkyl nucleobases in good yields. This methodology is highly efficient for various structurally diverse primary alcohols. 相似文献
2.
Mohammad Navid Soltani Rad Somayeh Behrouz Ali Khalafi-Nezhad 《Tetrahedron letters》2008,49(7):1115-1120
An efficient and selective method for esterification of alcohols using N-(p-toluenesulfonyl)imidazole (TsIm) is described. In this method, alcohols are refluxed with a mixture of RCO2Na (R: alkyl and aryl), TsIm, and triethylamine in the presence of catalytic amounts of tetra-n-butylammonium iodide (TBAI) in DMF to afford the corresponding esters in good yields. This methodology is highly efficient for various structurally diverse alcohols with selectivity for ROH: 1° > 2° > 3°. 相似文献
3.
A simple one-pot procedure for the direct conversion of alcohols into azides using TsIm 总被引:1,自引:0,他引:1
A facile and efficient method for one-pot conversion of alcohols into azides using N-(p-toluenesulfonyl)imidazole (TsIm) is described. In this method, alcohols are refluxed with a mixture of NaN3, TsIm and triethylamine in the presence of catalytic amounts of tetra-n-butylammonium iodide (TBAI) in DMF affording the corresponding alkyl azides in good yields. This methodology is highly efficient for various structurally diverse alcohols with selectivity for ROH: 1° > 2° > 3°. 相似文献
4.
A variety of ketoximes, prepared from corresponding ketones, undergo Beckmann rearrangement using H3PW12O40 (DTPA) in acetonitrile under reflux to yield N-substituted amides and lactams in good to excellent yields (72–96%). The present method provides an efficient, clean, eco-friendly, and simple synthesis. The catalyst is cheap, moisture tolerant, recoverable, and reusable without much loss of its activity. 相似文献
5.
Dipak Patil 《合成通讯》2013,43(1):118-128
A rapid and efficient synthesis of amides via Beckmann rearrangement of ketoximes and dehydration of aldoximes to corresponding nitriles with good to excellent yields has been carried out in the presence of SOCl2/β-cyclodextrin under aqueous conditions. The β-cyclodextrin has been recovered and reused. 相似文献
6.
Mohammad Navid Soltani Rad Somayeh Behrouz Abdo-Reza Nekoei 《Phosphorus, sulfur, and silicon and the related elements》2013,188(4):465-476
Abstract A facile and efficient method for one-pot synthesis of N-alkyl sulfonamides from alcohols using N-(p-toluenesulfonyl)imidazole (TsIm) is described. In this protocol, treatment of various potassium sulfonylamide salts and alcohols in the presence of TsIm and triethylamine in refluxing DMF furnishes the corresponding N-alkyl sulfonamides in good to excellent yields. This methodology is highly efficient for reaction of various structurally diverse primary and secondary alcohols as well as potassium sulfonylamides. Also, the density functional theoretical calculations are employed to mechanistically study this protocol. [Supplementary materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements for the following free supplemental files: Additional text and figures.] 相似文献
7.
A facile and efficient method for dehydration of aldoximes into nitriles using N-(p-toluenesulfonyl) imidazole (TsIm) is described. In this method, aldoximes were refluxed with TsIm in the presence of 1,8-diazabicyclo-[5.4.0]undec-7-ene (DBU) in dimethylformamide (DMF) to afford the corresponding nitriles in good yields. This methodology is highly efficient for various structurally diverse aldoximes including aromatic, heteroaromatic, and aliphatic oximes. A plausible mechanism for the conversion of aldoxime into nitriles using TsIm/DBU is explained. 相似文献
8.
Mohammad Navid Soltani Rad Ali Khalafi-Nezhad Mohammad Ali Faghihi 《Tetrahedron letters》2007,48(38):6779-6784
A convenient and efficient one-pot preparation of nitriles from alcohols using N-(p-toluenesulfonyl)imidazole (TsIm) is described. In this method, treatment of alcohols with a mixture of NaCN, TsIm and triethylamine in the presence of catalytic amounts of tetra-n-butylammonium iodide (TBAI) in refluxing DMF furnishes the corresponding alkyl nitriles in good yields. This methodology is highly efficient for various structurally diverse alcohols with selectivity for ROH: 1° > 2° > 3°. 相似文献
9.
B.V. Subba Reddy N. Sivasankar Reddy Ch. Madan J.S. Yadav 《Tetrahedron letters》2010,51(37):4827-8621
A variety of alkenes undergo smooth amidation with nitriles in the presence of HBF4·OEt2 at room temperature under mild conditions to afford the corresponding secondary amides in good to excellent yields. This is a highly efficient method for the preparation of α-aryl ethyl amides especially from vinyl arenes without any side reactions such as olefin polymerization. The use of readily available and easy to handle reagent HBF4·OEt2 makes this method simple, convenient, and practical. 相似文献
10.
Hai-Tao Yang Wen-Long Ren Chun-Ping DongYang Yang Xiao-Qiang SunChun-Bao Miao 《Tetrahedron letters》2013
An efficient synthesis of fullerooxazoles was developed via PhI(OAc)2/I2-mediated [3+2] reaction of C60 with amides under photo-irradiation. The reaction was tolerant to various aryl and alkyl amides. The reaction mechanism was investigated in detail and a radical pathway was proposed for the formation of fullerooxazoles. Further transformation of compound 2l allowed the easy conjunction of fullerooxazole moiety to other molecular skeletons. 相似文献
11.
S. S. Vorob’ev M. D. Dutov I. A. Vatsadze E. P. Petrosyan V. V. Kachala Yu. A. Strelenko S. A. Shevelev 《Russian Chemical Bulletin》2007,56(5):1020-1027
O-(3,5-Dinitrophenyl) ketoximes obtained in the reactions of ketoximes with 1,3,5-trinitrobenzene undergo acid-catalyzed cyclization
into 2-substituted or 2,3-disubstituted 4,6-dinitrobenzo[b]furans. In analogous cyclization, products of selective reduction of a nitro group in O-(3,5-dinitrophenyl) ketoximes unexpectedly yield, along with 6-amino-4-nitrobenzofurans, 4-hydroxy-6-nitroindoles. The 4-NO2 group is displaced from 4,6-dinitrobenzo[b]furans in reactions with thiols in the presence of K2CO3. Conditions for nitration and sulfochlorination of 4,6-dinitrobenzo[b]furans in position 3 were found. Condensation of a 2-methyl derivative with dimethylformamide acetal was accomplished.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 984–991, May, 2007. 相似文献
12.
An efficient and scalable process for the synthesis of antihypercholesterolemic drug ezetimibe through chiral Evans auxiliary (S)-4-phenyl-2-oxazolidinone is described. The key steps in this process are the condensation of (S)-3-(5-(4-fluorophenyl)-5,5-dimethoxypentanoyl)-4-phenyloxazolidin-2-one and N-(4-((tert-butyldimethylsilyl)oxy)benzylidene)-4-fluoroaniline, and the stereoselective reduction of ezetimibe-ketone with NaBH4/I2, which is first applied in the synthesis of ezetimibe. The process is concise, mild, easy to operate, and highly stereoselective (99.6% of de value of ezetimibe). In addition, three diastereomers of ezetimibe are synthesized and served as the references in quality control of the product. 相似文献
13.
《合成通讯》2013,43(16):2535-2541
ABSTRACT Primary amides and aldoximes are easily converted to their corresponding nitriles using a mixture of triphenylphosphine and N-chlorosuccinimide in dichloromethane at room temperature. The reaction of aldoximes occurs almost immediately and primary amides in 0.5?h by this method. By this procedure secondary amides are produced by Beckmann rearrangement of ketoximes. 相似文献
14.
G. Kumaraswamy A. Pitchaiah G. Ramakrishna D.S. Ramakrishna K. Sadaiah 《Tetrahedron letters》2006,47(12):2013-2015
An efficient protocol for the benzylation or allylation of amides using the corresponding benzyl or allyl chlorides as electrophiles under basic conditions with commercially available 5 mol % of [Cu(OH)TMEDA]2Cl2 as catalyst was developed. Under these conditions, unprotected amino acids were benzylated without any racemization. 相似文献
15.
The use of Ph3P/DDQ offers a novel, neutral and highly efficient method for the efficient conversion of 2-hydroxyaryl aldoximes and ketoximes to 1,2-benzisoxazoles in excellent yields at room temperature. 相似文献
16.
Ruthenium‐Catalyzed Oxidant‐Free Allylation of Aromatic Ketoximes with Allylic Acetates at Room Temperature
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Rajendran Manikandan Padmaja Madasamy Dr. Masilamani Jeganmohan 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(40):13934-13938
Substituted aromatic ketoximes reacted efficiently with allylic acetates in the presence of {[RuCl2(p‐cymene)]2} and AgSbF6 in 1,2‐dichloroethane at ambient temperature, providing ortho‐allyl aromatic ketoximes in a highly regioselective manner without an oxidant. In the reaction, the acetate group of allyl acetate acts as a base to activate the C?H bond of aromatics. Later, ortho‐allyl aromatic ketoximes were converted into ortho‐allyl aromatic ketones in the presence of HCl. 相似文献
17.
Synthesis of 1‐Acyl‐3,4‐dihydroquinazoline‐2(1H)‐thiones by Cyclization of N‐[2‐(Isothiocyanatomethyl)phenyl] Amides Generated in situ from N‐[2‐(Azidomethyl)phenyl] Amides
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An efficient method for the preparation of 1‐acyl‐3,4‐dihydroquinazoline‐2(1H)‐thiones 5 has been developed. The reaction of N‐[2‐(azidomethyl)phenyl] amides 3 , easily prepared by a three‐step sequence starting with (2‐aminophenyl)methanols, with Ph3P, followed by CS2, allowed generation of N‐[2‐(isothiocyanatomethyl)phenyl]‐amide intermediates 4 , which underwent cyclization on treatment with NaH to furnish the corresponding desired products in generally good yields. 相似文献
18.
19.
The ring-opening reaction of styrene oxide with various nitrogen, oxygen, and carbon nucleophiles catalyzed by MoO2(acac)2 was described. The corresponding ring-opening compounds with nearly 100% regioselectivities were obtained under mild conditions in moderate to good yields. MoO2(acac)2 is a highly efficient catalyst for the ring opening of styrene oxide. The reaction serves as a simple and efficient method for the synthesis of 1,2-bifunctional compounds. 相似文献
20.
BF3·OEt2 (Boron trifluoride etherate), an inexpensive and commercially easily available Lewis acid stoichiometrically employed for Beckamann rearrangement in general, was now found to efficiently catalyze Beckmann rearrangement of ketoximes into their corresponding amides (up to 99% yield) in anhydrous acetonitrile under reflux temperature. 相似文献