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A tandem one‐pot synthesis of polysubstituted 1,3‐thiazines has been developed by reacting with cyanoacetamide and isothiocyanate derivatives to give rise to 2‐cyano‐3‐mercaptoacrylamides, which are trapped in situ by various aldehydes or diversely substituted ketones through intermolecular cyclization, providing polysubstituted 1,3‐thiazine derivatives in short reaction times with good to excellent yields. The salient features of this novel protocol are operational simplicity, accessing the desired products from the readily available starting materials and easy of product isolation and may find wide spread applications in medicinal chemistry. 相似文献
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Unexpected 4,4′‐dipyrazolomethylidene ( 7 ), 4‐amino‐3a‐bromo‐3‐methyl‐1‐phenylpyrazolo[3,4‐b]pyridin‐6‐thione ( 9 ), 4,4′‐dipyrazolyl ( 18 ), ethyl 4‐(3‐methyl‐1‐phenylpyrazole‐4‐yl)fuoro[2,3‐c]pyrazole‐4‐carboxylate ( 25 ), as well as the expected fuoro[2,3‐c]pyrazole derivatives ( 15 ), ( 20 ) and ( 28 ) were isolated from a one‐pot reaction of 4‐bromo‐3‐methyl‐1‐phenylpyrazole ( 1 ) with some readily available reagents. 相似文献
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Synthesis of Polysubstituted α‐Pyrones Using Zinc‐Catalyzed Addition–Cyclization Reactions
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Various polysubstituted α‐pyrone derivatives have been directly synthesized via a hydroalkylation of Michael additional reaction following a cyclized process catalyzed by the Lewis acid of Zn(OAc)2. This protocol provides a new convenient and step‐economical route to construct heterocycles. Fourteen examples are obtained from easily available materials with moderate to good yields. 相似文献
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An efficient method for the synthesis of polysubstituted indolizines has been developed based on formal [4+2] annulation of 1‐acetylaryl 2‐formylpyrroles with enals, followed by oxidative aromatization. Pyridine‐type six‐membered rings were constructed in this transformation. This transition metal‐free reaction features mild reaction conditions, a broad substrate scope, and excellent functional group tolerance. Notably, the formyl group is well tolerated under reaction conditions. 相似文献
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Korany A. Ali Heba S. Abdalghfar Khaled Mahmoud Eman A. Ragab 《Journal of heterocyclic chemistry》2013,50(5):1157-1164
The versatile multifunctional unreported pyridine‐2,6‐bis(2‐cyano‐N‐phenyl‐3‐oxopropanethioamide) ( 3 ) was prepared starting from pyridine‐2,6‐bis‐(3‐oxopropanenitrile) ( 1 ). Several new series of polysubstituted thiophenes and 1,3,4‐thiadiazoles incorporating 2,6‐pyridine moiety were efficiently synthesized. The newly synthesized compounds were evaluated for their in vitro anticancer activity against human cancer cell lines: hepatocellular liver carcinoma (HEPG2) and Caucasian breast adenocarcinoma (MCF‐7). Some of the newly synthesized compounds exhibited better activity than doxorubicin as a reference drug. 相似文献
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Synthesis of Polysubstituted Pyrazolo[3,4‐b]pyridine‐3‐Carbohydrazide and Pyrazolo[3,4‐d]pyridazine Derivatives
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Dinesh C. Bhavsar Prashant S. Nikam Sachin A. Gangurde Raghunath B. Toche 《Journal of heterocyclic chemistry》2014,51(3):635-641
5‐Amino‐4‐formyl pyrazole carboxylate gave facile reactions with malononitrile, hydrazine, and ketones in the presence of piperidine furnished substituted pyrazolo[3,4‐b]pyridines and pyrazolo[3,4‐b]quinolones. The pyridazine sulfonamides were obtained by the reaction of 5‐chloro 4‐formyl pyrazole carboxylate with sulfonamide derivatives. 相似文献
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Minhang Xin Ying Gao Hua Xiang Dong Chen Yi He Qidong You 《Journal of heterocyclic chemistry》2013,50(1):169-174
A simple and efficient approach to synthesize novel polysubstituted quinazolin‐4(3H)‐ones has been developed, and the key step is a sequential procedure involved iron‐mediated reduction and acid‐catalytic cyclization. The present method provides a convenient and practical strategy for the synthesis of quinazolin‐4(3H)‐one derivatives. 相似文献
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《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2018,130(32):10509-10513
The imino‐Nazarov cyclization of the polysubstituted pentan‐1,4‐diene‐3‐imines was realized. To this aim, a one‐pot procedure involving reductive alkenyliminylation of α,β‐unsaturated secondary amides with potassium organotrifluoroborates, followed by acid‐catalyzed imino‐Nazarov cyclization of the polysubstituted pentan‐1,4‐diene‐3‐imine intermediates, was studied systematically. This mild, operationally simple, flexible, and high‐yielding protocol efficiently affords polysubstituted pentan‐1,4‐diene‐3‐imines, cyclopentenimines, and α‐amino cyclopentenones, which are useful scaffolds in organic synthesis. The substituent effect at the C2 position of the polysubstituted pentan‐1,4‐diene‐3‐imines was studied by means of density‐functional theory calculations. Results suggested that the electron‐donating group facilitates the imino‐Nazarov cyclization process. 相似文献
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Fengjin Wu Dr. Leifeng Wang Prof. Dr. Jiean Chen Prof. Dr. David A. Nicewicz Prof. Dr. Yong Huang 《Angewandte Chemie (International ed. in English)》2018,57(8):2174-2178
Aldehydes are among the most versatile functional groups for synthetic chemistry. However, access to polysubstituted alkyl aldehydes is very limited and requires lengthy synthetic routes that involve multiple‐step functional‐group conversion. This paper reports a one‐step synthesis of polysubstituted aldehydes from readily available olefin substrates using visible‐light photoredox catalysis. Despite a number of competing reaction pathways, commercial styrenes react with vinyl ethers selectively in the presence of an acridinium salt photooxidant and a disulfide hydrogen‐atom‐transfer catalyst under blue LED irradiation. Alkyl aldehydes with different substitution patterns are prepared in good yields. This strategy can be applied to structurally sophisticated substrates. 相似文献
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《中国化学》2018,36(6):519-525
A gold(I)‐catalyzed highly diastereo‐ and enantioselective intermolecular cycloaddition of oxime ethers with nitrones under mild conditions was developed, which provides an facile access to optically pure highly substituted pyrrolo[3,4‐d][1,2]oxazines. The salient features of this reaction include general substrate scope, high efficiency, high enantioselectivity, readily available starting materials, and the use of commercially available ligand. 相似文献
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Lucie echov Juraj Filo Martin Dra
ínský Chavdar Slavov Dazhong Sun Zlatko Janeba Tom Slanina Josef Wachtveitl Elika Prochzkov Marek Cig 《Angewandte Chemie (International ed. in English)》2020,59(36):15590-15594
Photochromic systems with an ultrahigh rate of thermal relaxation are highly desirable for the development of new efficient photochromic oscillators. Based on DFT calculations, we designed a series of 5‐phenylazopyrimidines with strong push–pull character in silico and observed very low energy barriers for the thermal (Z)‐to‐(E) isomerization. The structure of the (Z)‐isomer of the slowest isomerizing derivative in the series was confirmed by NMR analysis with in situ irradiation at low temperature. The substituents can tune the lifetime of thermal back isomerization from hundreds of microseconds to several nanoseconds (8 orders of magnitude). The photoswitching parameters were extracted from transient absorption techniques and a dominant rotation mechanism of the (Z)‐to‐(E) thermal fading was proposed based on DFT calculations. 相似文献
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Synthesis of Polysubstituted Benzenes via the Vinylogous Michael Addition of Alkylidenemalononitriles to 2‐(1,3‐Dioxo‐1H‐inden‐2(3H)‐ylidene)malononitrile
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Abdolali Alizadeh Hadi Sedighian Seyed Yasub Hosseini Long‐Guan Zhu 《Helvetica chimica acta》2015,98(4):569-574
An efficient synthesis for polysubstituted benzenes was successfully developed by the reaction of ninhydrin (=2,2‐dihydroxyindane‐1,3‐dione), malononitrile (=propanedinitrile), and alkylidenemalononitrile. The method involves vinylogous Michael addition of alkylidenemalononitrile to 2‐(1,3‐dioxo‐1H‐inden‐2(3H)‐ylidene)malononitrile, which formed by condensation of malononitrile and ninhydrin in the presence of Et3N, and the alcoholic solvent has participated in the reaction as a reagent. The method has the advantages of good yields and of not requiring a metal catalyst. The structures were confirmed spectroscopically (IR, 1H‐ and 13C‐NMR, and EI‐MS) and by elemental analyses, and, in the case of 2c , by X‐ray crystallography. A plausible mechanism for this reaction is proposed (Scheme). 相似文献