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1.
An Efficient Synthesis of 3‐(3‐benzyl‐2‐(phenylimino)‐2,3‐dihydrothiazol‐4‐yl)‐6‐methyl‐4‐(2‐oxo‐2‐phenylethoxy)‐3,4‐dihydro‐2H‐pyran‐2‐one Derivatives via Multi‐Component Approach 下载免费PDF全文
An easy, highly efficient and a new convenient one‐pot, two‐step approach to the synthesis of 3‐(3‐benzyl‐2‐(phenylimino)‐2,3‐dihydrothiazol‐4‐yl)‐6‐methyl‐4‐(2‐oxo‐2‐phenylethoxy)‐3,4‐dihydro‐2H‐pyran‐2‐one is described. These compounds were synthesized from 3‐(3‐benzyl‐2‐(phenylimino)‐2,3‐dihydrothiazol‐4‐yl)‐4‐hydroxy‐6‐methyl‐3,4‐dihydro‐2H‐pyran‐2‐one and α‐bromoketones in good yields. The compounds 4 were synthesized by a multi‐component reaction between 1 , 2 , and 3 and the prominent features of this protocol are mild reaction conditions, operation simplicity, and good to high yields of products. 相似文献
2.
Selective α-Bromination of β-Keto Esters in Reusable PEG-400 under Mild and Catalyst-free Conditions
An efficient bromination protocol for the synthesis of α-bromo-β-keto esters has been developed. In PEG-400 (poly(ethylene glycol-400)), a variety of β-keto esters were treated with NBS (N-bromosuccinimide) at room temperature to selectively afford the corresponding α-monobromination products in excellent yields. It is noteworthy that the reaction was conducted under mild, environmentally benign and catalyst-free conditions. 相似文献
3.
Microwave‐assisted Synthesis of 6‐{(5‐Aryl‐1,3,4‐oxadiazol‐2‐yl)methyl}‐6H‐indolo[2,3‐b]quinoxalines 下载免费PDF全文
Sreenivas Avula Jayaram Reddy Komsani Satish Koppireddi Rambabu Yadla 《Journal of heterocyclic chemistry》2015,52(6):1737-1742
An efficient and convenient synthesis of a new series of 2‐{(6H‐indolo[2,3‐b]quinoxalin‐6‐yl)methyl}‐5‐aryl‐1,3,4‐oxadiazoles from readily available 1,2‐diaminobenzene and isatins under microwave irradiation conditions was disclosed. The 6‐{(5‐aryl‐1,3,4‐oxadiazol‐2‐yl)methyl}‐6H‐indolo[2,3‐b]quinoxalines were also prepared by the thermal cyclo‐condensation reaction of 2‐(6H‐indolo[2,3‐b]quinoxalin‐6‐yl)acetohydrazides with carboxylic acids in refluxing POCl3. The microwave‐assisted synthesis was rapid and resulted in higher yield of the products at lower operating temperature with reduced waste generation in comparison with the thermal reaction protocol. 相似文献
4.
Conghui Tang Mikiko Okumura Hejun Deng David Sarlah 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(44):15909-15913
A palladium‐catalyzed dearomative syn‐1,4‐oxyamination protocol using non‐activated arenes has been developed. This one‐pot procedure utilizes arenophile chemistry, and the corresponding para‐cycloadducts are treated with oxygen nucleophiles via formal allylic substitution, providing direct access to syn‐1,4‐oxyaminated products. The reaction conditions permit a range of arenes, as well as different O‐nucleophiles, such as oximes and benzyl alcohols. Moreover, this process was established in an asymmetric fashion, delivering products with high enantioselectivity. The dearomatized products are amenable to a multitude of further derivatizations ranging from olefin chemistry to C?H activation, giving rise to a diverse set of new functionalities. Overall, this dearomative functionalization offers rapid and controlled formation of molecular complexity, enabling straightforward access to functionalized small molecules from simple and readily available arenes. 相似文献
5.
A simple and efficient protocol has been developed for the synthesis of 3‐phenylnaphtho[2,3‐b]furan‐4,9‐diones by domino reaction of α‐bromonitroalkenes to 2‐hydroxynaphthalene‐1,4‐dione. With the optimal reaction conditions [NaOAc (120 mol%), water, 70°C, 7 h], the scope of the domino reaction was explored and the green approach provided the desired products in moderate to good yields at elevated temperature under aqueous‐mediated conditions. A mechanistic rationalization for this reaction is also provided. The absorption characteristics of the compounds were examined by UV‐Vis spectra and fluorescence spectroscopy. All compounds were fluorescent in solution emitting at blue light (432–433 nm), green light (512–536 nm), or yellow light (591 nm). 相似文献
6.
An efficient one‐pot four‐component protocol for the synthesis of imidazo[1,2‐a]pyridines was developed by condensing ethane‐1,2‐diamine ( 2 ), 1,1‐bis(methylthio)‐2‐nitroethene ( 1 ), aldehydes 3 , and activated methylene compounds in EtOH under reflux conditions (Tables 1–3). The features of this procedure are operational simplicity, good yields of products, in situ preparation of heterocyclic ketene aminals (HKA), and catalyst‐free conditions. 相似文献
7.
Oxidative acylation of α,α‐diarylallylic alcohols: Synthesis of 1,2,4‐triarylbutane‐1,4‐diones 下载免费PDF全文
Yong Li Yuting Leng Shiwei Wang Yuhui Gao Huiyan Lv Junbiao Chang Yusheng Wu Yangjie Wu 《应用有机金属化学》2018,32(8)
A metal‐free mediated oxidative acylation of α,α‐diarylallylic alcohols with simple aromatic aldehydes for the synthesis of 1,2,4‐triphenylbutane‐1,4‐diones is presented. In the presence of TBPB (tert‐butyl peroxybenzoate), desired products were obtained in good to excellent yields for 28 examples. This protocol features high regioselectivity, wide functional group tolerance and atom economy. 相似文献
8.
A facile one‐pot, three‐component protocol for the synthesis of novel spiro[3H‐indole‐3,2′‐thiazolidine]‐2,4′(1H)‐diones by condensing 1H‐indole‐2,3‐diones, 4H‐1,2,4‐triazol‐4‐amine and 2‐sulfanylpropanoic acid in [bmim]PF6 (1‐butyl‐3‐methyl‐1H‐imidazolium hexafluorophosphate) as a recyclable ionic‐liquid solvent gave good to excellent yields in the absence of any catalyst (Scheme 1 and Table 2). The advantages of this protocol over conventional methods are the mild reaction conditions, the high product yields, a shorter reaction time, as well as the eco‐friendly conditions. 相似文献
9.
An Environmentally Benign Multicomponent Synthesis of Some Novel 2‐Methylthio Pyrimidine Derivatives Using MCM‐41‐NH2 as Nanoreactor and Nanocatalyst 下载免费PDF全文
Some novel 4‐amino‐6‐aryl‐2‐methylthio pyrimidine‐5‐carbonitrile derivatives were synthesized through a one‐pot three‐component reaction of an aldehyde, malononitrile, and S‐methylisothiouronium iodide, using MCM‐41‐NH2 as nanoreactor and nanocatalyst. This protocol has some advantages including application of readily available and nonhazardous materials, benign reaction conditions (ambient temperature, solvent‐free, and one‐pot approach), easy work‐up, and high overall yields of the products. 相似文献
10.
Borax/phosphorous oxychloride (BPO) efficiently catalyzes the preparation of 1,5‐benzodiazepine derivatives of o‐phenylenediamines and ketones in solvent‐free and solution conditions. The reaction proceeds efficiently under ambient conditions giving excellent yields of the products. This new protocol allows the recycling of catalyst with no loss in its potency. 相似文献
11.
A general atom‐economical approach for the synthesis of α‐halomethyl ketones is demonstrated through Ce(SO4)2/acid co‐catalyzed hydration of a wide range of haloalkynes. The reactions are conducted under convenient conditions and provide products with excellent regioselectivity in good to excellent yields, with broad substrate scope. This protocol is an alternative to conventional α‐halogenation of ketones. 相似文献
12.
Yi‐Feng Wang Wei Zhang Shu‐Ping Luo Dr. Bai‐Lin Li Ai‐Bao Xia Ai‐Guo Zhong Dr. Dan‐Qian Xu Dr. 《化学:亚洲杂志》2009,4(12):1834-1838
Generally, amine‐catalyzed enantioselective transformations rely on chiral enamine or unsaturated iminium intermediates. Herein, we report a protocol involving dual activation by an aromatic iminium and hydrogen‐bonding. An enantioselective aza‐Michael–Henry domino reaction of 2‐aminobenzaldehydes with nitroolefins has been developed through this protocol using primary amine thiourea catalysts to provide a variety of 3‐nitro‐1,2‐dihydroquinolines in moderate yields and with up to 90 % ee. The mechanism for the catalytic enantioselective reaction was confirmed by ESI mass spectrometric detection of the reaction intermediates. The products formed are substructures found in skeletons of important biological and pharmaceutical molecules. 相似文献
13.
Kavitha Kotthireddy Srikrishna Devulapally Pramod Kumar Dubey Aparna Pasula 《Journal of heterocyclic chemistry》2019,56(3):938-946
A facile, convenient, and adequate method has been developed for the synthesis of novel 5‐amino‐3‐(2‐oxo‐2H‐chromen‐3‐yl)‐7‐aryl‐7H‐thiazolo[3,2‐a]pyridine‐6,8‐dicarbonitriles ( 6 ) by employing 2‐(4‐(2‐oxo‐2H‐chromen‐3‐yl)thiazol‐2‐yl)acetonitrile ( 3 ) as an important precursor. Initially, we have synthesized the target compounds in a stepwise manner and then approached a tandem method to examine the feasibility of one‐pot method. Subsequently, one‐pot three‐component protocol has been established for the synthesis of title compounds by the reaction of 3 with benzaldehyde and malononitrile in refluxing ethanol engender a new six‐membered thiazolo[3,2‐a] pyridine as a hybrid scaffold. Reaction conditions were optimized for this reaction and a broad substrate scope with various aryl and heteroaryl aldehydes make this protocol very practical, attractive, and worthy. Mechanistic aspects for the formation of these compounds were outlined comprehensively. Characterization of these newly synthesized compounds was achieved by means of IR, 1H NMR, 13C NMR, and HRMS. 相似文献
14.
An efficient synthesis of 12‐aryl or 12‐alkyl‐8,9,10,12‐tetrahydrobenzo[a]xanthen‐11‐one derivatives has been developed under solvent‐free conditions by one‐pot condensation of aldehydes, 2‐naphthol, and cyclic 1,3‐dicarbonyl compounds in the presence of a catalytic amount of methanesulfonic acid. The protocol has advantages of mild condition, short reaction time, high yield, and operational simplicity. 相似文献
15.
An Elegant Synthesis of a New Class of 1‐(Substituted)‐1H‐1,2,3‐triazol‐4‐yl)methyl)diphenylphosphineoxides by Microwave Irradiation 下载免费PDF全文
Radha Rani Chinthaparthi Chandra Sekhar Reddy Gangireddy Madhu Kumar Reddy Kandula Satheesh Krishna Balam Suresh Reddy Cirandur 《Journal of heterocyclic chemistry》2015,52(6):1876-1882
A simple and efficient one‐pot microwave‐assisted click formation of 1‐(substituted)‐1H‐1,2,3‐triazol‐4‐yl)methyl)diphenylphosphineoxide derivatives via Huisgen regioselective [3+2]‐cycloaddition of an in situ generated organic azides and diphenyl(prop‐2‐yn‐1‐yl)phosphine oxide in highly polar DMSO‐H2O medium. This synthetic protocol is mild, requires shorter reaction time, and afforded products in excellent yields with high regioselectivity. 相似文献
16.
Pavel Hradil Lubomír Kvapil Jan Hlav
Tom Weidlich Antonín Ly
ka Karel Lemr 《Journal of heterocyclic chemistry》2000,37(4):831-837
The cyclization of phenacyl anthranilate has been studied with the aim to develop the synthesis of 2‐(2′‐aminophenyl)‐4‐phenyloxazole. However, a different course of the reaction than expected was observed. 2‐Phenyl‐2‐hydroxymethyl‐4‐oxo‐1,2,3,4‐tetrahydroquinazoline ( 3a ) was formed by the reaction of phenacyl anthranilate ( 2 ) with ammonium acetate under various conditions. 3‐Hydroxy‐2‐phenyl‐4(1H)‐quinolinone ( 4 ) arose by heating compound 3a in acetic acid. The same compound was obtained by melting compound 3a , but the yield was lower. Different types of products resulted in the reaction of compound 3a with acetic anhydride. Under mild conditions acetylated products 2‐acetoxymethyl‐2‐phenyl‐4‐oxo‐1,2,3,4‐tetrahydroquinazoline ( 7a ) and 2‐acetoxymethyl‐3‐acetyl‐2‐phenyl‐4‐oxo‐1,2,3,4‐tetrahydroquinazoline ( 8 ) were prepared. If the reaction was carried out under reflux of the reaction mixture, molecular rearrangement took place to give cis and trans 2‐methyl‐4‐oxo‐3‐(1‐phenyl‐2‐acetoxy)vinyl‐3,4‐dihydroquinazolines ( 9a and 9b ). All prepared compounds have been characterised by their 1H, 13C and 15N NMR spectra, IR spectra and MS. 相似文献
17.
M. P. Stoyanova I. D. Kozekov M. D. Palamareva 《Journal of heterocyclic chemistry》2003,40(5):795-803
Stereochemical course of the reaction of homophthalic anhydride and N‐(1‐methyl‐1H‐pyrrol‐2‐yl‐methylidene)‐phenethylamine was studied. Mixtures of the expected trans‐ and cis‐1,2,3,4‐tetrahydroiso‐quinoline‐4‐carboxylic acids trans‐ 4 and cis‐ 4 were obtained along with by‐products 5 and 6 . The ratios of all products and the diastereomers, obtained under different reaction conditions, were established by pmr. THF as a solvent and ultrasonic treatment are applied for the first time in the reaction of this type. The reaction was made diastereoselective towards any isomer. The carboxylic group of trans‐ 4 was transformed in four steps into various cyclic amino‐methyl groups yielding numerous new tetrahydroisoquinolinones trans‐ 10a‐i incorporating a given fragment of pharmacological interest. Reduction of 10a‐i was studied. 相似文献
18.
Changsheng Yao Xiaodong Feng Cuihua Wang Bei Jiang Chenxia Yu Xiangshan Wang Tuanjie Li Shujiang Tu 《Journal of heterocyclic chemistry》2011,48(5):1111-1116
An efficient synthesis of 7‐aryl‐1,1‐dioxothieno[3,2‐b]pyran derivatives via the reaction of aryl aldehyde, tetrahydrothiophene‐3‐one‐1,1‐dioxide and malononitrile or ethyl 2‐cyanoacetate was performed at room temperature catalyzed by ammonium acetate under solvent‐free conditions. Compared with the conventional methods, this protocol features mild reaction conditions, high yields, and eco‐friendliness. J. Heterocyclic Chem., (2011). 相似文献
19.
V. Sridharan S. Muthusubramanian S. Pon Saravanakumar 《Journal of heterocyclic chemistry》2005,42(4):515-518
Three‐component stereoselective synthesis of a set of new tetra substituted isoxazolidines from 5‐substi‐tuted 2‐methoxybenzaldehydes, N‐phenylhydroxylamine and 1‐(2‐thienyl)‐3‐arylprop‐2‐en‐1‐ones has been achieved. The effect of microwave irradiation on the reaction under solvent‐free conditions has also been investigated. The stereochemistry of the final products has been confirmed by NMR and single crystal X‐ray analysis. 相似文献
20.
Chai‐Ho Lee Guo Fan Jin Hyun Wha Lim Eun Hye Yang Jong‐Dae Lee Hiroyuki Nakamura Hyun Seung Ban Sang Ook Kang 《Heteroatom Chemistry》2011,22(2):192-197
A new method for the preparation of 4‐substituted 3,4‐dihydro‐1H‐2,1,3‐benzothiadiazine 2,2‐dioxides is described. Treatment of t‐butyl N‐phenylsulfamoylcarbamate derivatives ( 1 ) with different aldehydes afforded the corresponding intramolecular cyclized products 2 under trifluoroacetic acid conditions. © 2011 Wiley Periodicals, Inc. Heteroatom Chem 22:192–197, 2011; View this article online at wileyonlinelibrary.com . DOI 10.1002/hc.20670 相似文献