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1.
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   

2.
A series of highly stereoselective polysubstituted cyclopropane derivatives were synthesized via one‐pot two‐step tandem reaction starting from pyridine, 4‐chloro phenacyl bromide, 1,3‐indandione and aromatic aldehydes in acetonitrile using triethylamine as catalyst. Pyridinium ylide generated from 4‐chloro phenacyl bromide undergo cyclopropanation with 2‐arylidene‐2H‐indene‐1,3‐dione in situ afford the title compounds. Structures of all the compounds were confirmed by their analytical and spectral studies. Single crystal X‐ray analysis was also performed on compound 4c in order to determine the crystal structure. All the compounds were screened for antimicrobial and nematicidal activities. Significant antimicrobial activity was shown by the compounds derived from 2‐hydroxybenzaldehyde ( 4i ) and 4‐(dimethylamino)benzaldehyde ( 4m ) against all the tested bacterial and fungal strains. Compound 4i has shown good activity (48% mortality) against Meloidogyne incognita after 48 h of exposure at 250 µg/mL concentration.  相似文献   

3.
The chemoselectivity in the reaction of 2‐diazo‐3‐oxo‐3‐phenylpropanal ( 1 ) with aldehydes and ketones in the presence of Et3N was investigated. The results indicate that 1 reacts with aromatic aldehydes with weak electron‐donating substituents and cyclic ketones under formation of 6‐phenyl‐4H‐1,3‐dioxin‐4‐one derivatives. However, it reacts with aromatic aldehydes with electron‐withdrawing substituents to yield 1,3‐diaryl‐3‐hydroxypropan‐1‐ones, accompanied by chalcone derivatives in some cases. It did not react with linear ketones, aliphatic aldehydes, and aromatic aldehydes with strong electron‐donating substituents. A mechanism for the formation of 1,3‐diaryl‐3‐hydroxypropan‐1‐ones and chalcone derivatives is proposed. We also tried to react 1 with other unsaturated compounds, including various olefins and nitriles, and cumulated unsaturated compounds, such as N,N′‐dialkylcarbodiimines, phenyl isocyanate, isothiocyanate, and CS2. Only with N,N′‐dialkylcarbodiimines, the expected cycloaddition took place.  相似文献   

4.
The reaction of the intermediate ketene N,Se‐hemiacetal 3 , prepared from cyanomethylene derivatives 1 by treatment with Et3N and aryl isoselenocyanates 2 , with bis‐electrophiles 6, 7, 9 , and 11 in DMF affords tetrahydro‐1H‐1,3‐selenazine (=1,3‐selenazinane) derivatives 8, 10 , and 12 in good yield (Scheme 2 and Tables 1–3). Chemical and spectroscopic evidence for the structures of the new compounds are described. The structures of 8d and 12e are established by X‐ray crystallography (Figs. 1 and 2).  相似文献   

5.
Rong Yao  Eryan Xia  Jing Sun  Chaoguo Yan 《中国化学》2011,29(11):2461-2464
The polysubstituted thiophene derivatives were conveniently prepared by the four‐component reactions of 1,3‐thiazolidinedione, aromatic aldehydes, cyanoacetamide and cyclic secondary amines such as pyrrolidine, morpholine and piperidine. The reaction mechanism is believed to involve domino reactions of Knoevenagel condensation, Michael addition, ring‐opening and recyclization of 1,3‐thiazolidinedione.  相似文献   

6.
Novel polysubstituted ‐1,5‐benzothiazepine, ‐1,5‐benzoxazepine, and ‐1,5‐benzodiazepine were prepared in good yields by the reaction of hydrazono derivatives with o‐thioaminophenol, o‐aminophenol and o‐phenylenediamine via a one‐pot reaction.  相似文献   

7.
The [3,3′(4H,4′H)‐bi‐2H‐1,3‐oxazine]‐4,4′‐diones 3a – 3i were obtained by [2+4] cycloaddition reactions of furan‐2,3‐diones 1a – 1c with aromatic aldazines 2a – 2d (Scheme 1). So, new derivatives of bi‐2H‐1,3‐oxazines and their hydrolysis products, 3,5‐diaryl‐1H‐pyrazoles 4a – 4c (Scheme 3), which are potential biologically active compounds, were synthesized for the first time.  相似文献   

8.
Lactone analogues of 3‐substituted oxindoles (=1,3‐dihydro‐2H‐indol‐2‐ones) and nonbenzoid oxa‐analogous isoindigoid or nonbenzoid isoindigoid dyes were prepared by the reactions of furan‐2,3‐diones with oxindole and Lawesson reagent (Schemes 1 and 3), respectively. So, new derivatives of 2‐oxobutanoic acid, bis‐furanone, and bis‐pyrrolone, which are potentially biologically active compounds, were synthesized for the first time.  相似文献   

9.
A concise and efficient approach to the spiro‐tetrahydroisoquinoline derivatives has been developed by 1,4‐dipolar cycloaddition of zwitterions resulting from isoquinoline and acetylene esters and (1,3‐dihydro‐1,3‐dioxo‐2H‐inden‐2‐ylidene)malononitrile in MeCN at room temperature. The significance of this method lies in good yields and ease of product purification, and no inert atmosphere is required. The structures of the products were confirmed spectroscopically (IR, 1H‐ and 13C‐NMR, and EI‐MS) and by elemental analyses. A plausible mechanism for this reaction is proposed (Scheme).  相似文献   

10.
Shusu Shen  Yu Liu 《中国化学》2014,32(11):1107-1110
By the treatment of N‐3‐bromo‐3‐alkenylthioamides with sodium hydroxide in DMF‐H2O in the presence of tetra‐butylammonium bromide, series of 6‐alkylidene‐5,6‐dihydro‐4H‐1,3‐thiazine derivatives were prepared in moderate to good yields. The cyclization is supposed to proceed via both the intramolecular vinylic nucleophilic substitution and the elimination‐addition mechanisms (formation of acetylenic intermediates) in a competitive manner.  相似文献   

11.
An unprecedented KI/tert‐butyl hydroperoxide promoted tandem Michael addition/oxidative annulation of allene‐1,3‐dicarboxylic esters and 1,3‐dicarbonyl compounds has been developed. This procedure provides a new, facile, and transition‐metal‐free synthetic approach to afford polysubstituted furans in moderate to excellent yields (up to 93 %). This method first establishes a α,β‐double electrophilic reaction mode of allene‐1,3‐dicarboxylic esters to form 1,3‐dicarbonyl compounds.  相似文献   

12.
The catalytic diastereodivergent construction of stereoisomers having two or more stereogenic centers has been extensively studied. In contrast, the switchable introduction of another stereogenic element, that is, Z/E configuration involving a polysubstituted alkene group, into the optically active stereoisomers, has not been recognized yet. Disclosed here is the pseudo‐stereodivergent synthesis of highly enantioenriched tetrasubstituted alkene architectures from isatin‐based Morita–Baylis–Hillman carbonates and allylic derivatives, under the cooperative catalysis of a tertiary amine and a chiral iridium complex. The success of the switchable construction of the tetrasubstituted alkene motif relies on the diastereodivergent 1,3‐oxo‐allylation reaction between N‐allylic ylides and chiral π‐allyliridium complex intermediates by ligand and substrate control, followed by the stereoselective concerted 3,3‐Cope rearrangement process.  相似文献   

13.
1,3‐Dichloro‐tetra‐n‐butyl‐distannoxane was firstly used to catalyze the direct substitution of 9H‐xanthen‐9‐ol with indoles at room temperature to afford a class of 3‐(9H‐xanthen‐9‐yl)‐1H‐indole derivatives in good to excellent isolating yield. Moreover, other nucleophiles (such as diketone and pyrrole) could also proceed smoothly in this methodology. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

14.
The reactions of 5‐benzylidene‐3‐phenylrhodanine ( 2 ; rhodanine=2‐thioxo‐1,3‐thiazolidin‐4‐one) with diazomethane ( 7a ) and phenyldiazomethane ( 7b ) occurred chemoselectively at the exocyclic C?C bond to give the spirocyclopropane derivatives 9 and, in the case of 7a , also the C‐methylated products 8 (Scheme 1). In contrast, diphenyldiazomethane ( 7c ) reacted exclusively with the C?S group leading to the 2‐(diphenylmethylidene)‐1,3‐thiazolidine 11 via [2+3] cycloaddition and a ‘two‐fold extrusion reaction’. Treatment of 8 or 9b with an excess of 7a in refluxing CH2Cl2 and in THF at room temperature in the presence of [Rh2(OAc)4], respectively, led to the 1,3‐thiazolidine‐2,4‐diones 15 and 20 , respectively, i.e., the products of the hydrolysis of the intermediate thiocarbonyl ylide. On the other hand, the reactions with 7b and 7c in boiling toluene yielded the corresponding 2‐methylidene derivatives 16, 21a , and 21b . Finally, the reaction of 11 with 7a occurred exclusively at the electron‐poor C?C bond, which is conjugated with the C?O group. In addition to the spirocyclopropane 23 , the C‐methylated 22 was formed as a minor product. The structures of the products (Z)‐ 8, 9a, 9b, 11 , and 23 were established by X‐ray crystallography.  相似文献   

15.
A new strategy for the one‐pot synthesis of polysubstituted benzenes through a N,N‐dimethyl‐4‐aminopyridine (DMAP)‐catalyzed [4+2] benzannulation from readily prepared 1,3‐bis(sulfonyl)butadienes and γ‐substituted allenoates is described. This method provides a facile, metal‐free and general route to highly substituted benzenes under mild conditions in moderate‐to‐good yields with complete regioselectivity.  相似文献   

16.
The reactions of thiobenzamide 8 with diazo compounds proceeded via reactive thiocarbonyl ylides as intermediates, which underwent either a 1,5‐dipolar electrocyclization to give the corresponding five membered heterocycles, i.e., 4‐amino‐4,5‐dihydro‐1,3‐thiazole derivatives (i.e., 10a, 10b, 10c , cis‐ 10d , and trans‐ 10d ) or a 1,3‐dipolar electrocyclization to give the corresponding thiiranes as intermediates, which underwent a SNi′‐like ring opening and subsequent 5‐exo‐trig cyclization to yield the isomeric 2‐amino‐2,5‐dihydro‐1,3‐thiazole derivatives (i.e., 11a, 11b, 11c , cis‐ 11d , and trans‐ 11d ). In general, isomer 10 was formed in higher yield than isomer 11 . In the case of the reaction of 8 with diazo(phenyl)methane ( 3d ), a mixture of two pairs of diastereoisomers was formed, of which two, namely cis‐ 10d and trans‐ 10d , could be isolated as pure compounds. The isomers cis‐ 11d and trans‐ 11d remained as a mixture. In the reactions of the thioxohydrazone 9 with diazo compounds 3b and 3d , the main products were the alkenes 18 and 23 , respectively. Their formation was rationalized by a 1,3‐dipolar electrocyclization of the corresponding thiocarbonyl ylide and subsequent desulfurization of the intermediate thiiran. As minor products, 2,5‐dihydro‐1,3‐thiazol‐5‐amines 21 and 24 were obtained, which have been formed by 1,5‐dipolar electrocyclization of the thiocarbonyl ylide, followed by a 1,3‐shift of the dimethylamino group.  相似文献   

17.
The 2‐thienyl‐substituted 4,5‐dihydrofuran derivatives 3 – 8 were obtained by the radical cyclization reaction of 1,3‐dicarbonyl compounds 1a – 1f with 2‐thienyl‐substituted conjugated alkenes 2a – 2e by using [Mn(OAc)3] (Tables 15). In this study, reactions of 1,3‐dicarbonyl compounds 1a – 1e with alkenes 2a – 2c gave 4,5‐dihydrofuran derivatives 3 – 5 in high yields (Tables 13). Also the cyclic alkenes 2d and 2e gave the dihydrobenzofuran compounds, i.e., 6 and 7 in good yields (Table 4). Interestingly, the reaction of benzoylacetone (=1‐phenylbutane‐1,3‐dione; 1f ) with some alkenes gave two products due to generation of two stable carbocation intermediates (Table 5).  相似文献   

18.
The X‐ray crystal analyses of the two 11‐deoxy‐didehydrohexahydrobenzo[c]phenanthridine‐type alkaloid derivatives 3 and 4 , derived from (±)‐corynoline ( 1 ) and (+)‐chelidonine ( 2 ), established their structures as (±)‐(5bRS,12bRS)‐5b,12b,13,14‐tetrahydro‐5b,13‐dimethyl[1,3]benzodioxolo[5,6‐c]‐1,3‐dioxolo[4,5‐i]phenanthridine ( 3 ) and (+)‐rel‐(12bR)‐7,12b,13,14‐tetrahydro‐13‐methyl[1,3]benzodioxolo[5,6‐c]‐1,3‐dioxolo[4,5‐i]phenanthridine ( 4 ). The conformations of 3 and 4 in CDCl3 were determined on the basis of 1H‐ and 13C‐NMR spectroscopy.  相似文献   

19.
The three‐component reaction of the zwitterions generated from dialkyl acetylenedicarboxylates (=dialkyl but‐2‐ynedioates and triphenylphosphine (Ph3P) with isoindoline‐1,3‐diimine (=1H‐isoindole‐1,3(2H)‐diimine) is described (Scheme 1). This reaction affords the corresponding special type of substituted dihydropyrimido[2,1‐a]isoindole derivatives in good yields without using any catalyst and activation (Table).  相似文献   

20.
Selected 5‐substituted derivatives 4 of 1,1‐diethoxy‐5‐hydroxypent‐3‐yn‐2‐one were treated with propane‐1,3‐dithiol under various conditions. The unprotected hydroxy ketones underwent cyclization during the dithiol addition and gave the corresponding 3‐(diethoxymethyl)‐2‐oxa‐6,10‐dithiaspiro[4.5]decan‐3‐ols 5 in 80–90% yield as the only products (Scheme 3 and Table 1). These products can be regarded as partly modified carbohydrates in the furanose form. When the benzyl‐protected analogues 10‐Bn of the 1,1‐diethoxy‐5‐hydroxypent‐3‐yn‐2‐one derivatives were treated with the same dithiol, however, no cyclization occurred; instead the corresponding 3‐{2‐[(benzyloxy)methyl]‐1,3‐dithian‐2‐yl}‐1,1‐diethoxypropan‐2‐one derivatives 11‐Bn were formed in good yield (up to 99%; Table 4). These 1,3‐dithianes were and are in the process of being converted to a number of new carbohydrate analogues, and here are reported high‐yield syntheses of functionalized molecules 17 belonging to the 5,5‐diethoxy‐1,4‐dihydroxypentan‐2‐one family of compounds (Table 7), via 15‐Bn (Table 5) and 16‐Bn (Table 6 and Scheme 8).  相似文献   

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