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1.
Bahja Mahmoud 《Tetrahedron letters》2007,48(29):5091-5094
Cross-conjugated 1,4-pentadien-3-ones undergo electrocyclization to 2-oxidocyclopentenyl cations upon treatment with BF3·OEt2. When these reactions are carried out in the presence of electron-rich vinyl sulfides, nucleophilic trapping followed by ring-closure furnishes bridged bicyclic products that can be viewed as formal 3+2 cycloadducts. This process results in three new carbon-carbon bonds and establishes up to five new stereocenters. 相似文献
2.
研究了烷基苯基硅铜酸盐与2-环烯酮的1,4-加成反应的立体选择性, 并合成了一系列新的2-取代-3-硅基环烷酮. 结果表明, 在0 ℃下用饱和NH4Cl溶液处理, 烷基苯基硅铜酸盐与2-芳基-2-环烯酮的1,4-加成反应的立体选择性不同程度地受芳基和环的大小影响, 得到顺、反两种产物; 并首次发现室温下用甲醇处理反应时, 其立体选择性不受或者很少受环大小、芳基的性质以及与硅原子相连的取代基的影响, 只得到反式产物. 芳基溴甲烷与由烷基苯基硅铜酸盐与2-环烯酮1,4-加成所得的烯醇盐反应时, 只得到反式产物. 合成产物的结构用IR, 1H NMR, 13C NMR, MS和HRMS等进行了表征. 相似文献
3.
Witold Winnik 《Journal of heterocyclic chemistry》1995,32(2):477-482
3-Amino-4-(anilinothiomethylidene)-2-cyano-2-pentenedioic acid diethyl ester reacts with ethylenedi-amine, 1,3-propylenediamine and 1,4-butylenediamine affording bicyclic cyclocondensation products. The title compound reacts with diethylenetriamine and 2-(2-aminoethylamino)ethanol to give new seven membered ring tricyclic compounds. The mechanism for these reactions is discussed. 相似文献
4.
Palladium/CuI catalyzed reactions of 2-iodo-3-iodomethyl-1,4-diarylnaphthalenes in the presence of arylacetylenes produced the corresponding sp3-sp3 homo-coupling products 1,2-bis(3-iodonaphthalen-2-yl)ethane in moderate to good yields. 相似文献
5.
Phosphine-catalyzed [4 + 2] annulation and vinylogous Michael addition reactions between 1,4-dien-3-ones and 1,1-dicyanoalkenes are presented. Under the catalysis of PBu(3) (20 mol %), 1,4-dien-3-ones like styryl ketones with 2-aryl 1,1-dicyanoalkenes as doubly activated alkenes readily undergo a formal [4 + 2] cycloaddition reaction, affording polysubstituted cyclohexanones in satisfactory yield and good diastereoselectivity; with the doubly activated alkenes bearing an acidic methyl or methylene at the 2-position, a vinylogous Michael addition of 1,4-dien-3-ones occurs under the same reaction conditions, giving a non-cyclized multifunctional adduct in good yield. These two phosphine-catalyzed transformations represent atom economical carbon-carbon bond forming reactions capable of rapid construction of molecular complexity. Based on experimental results, formation of the products has been mechanistically rationalized, and a phosphonium activation is proposed. 相似文献
6.
V. I. Pavlovsky S. Yu. Bachinskii N. A. Tkachuk S. Yu. Makan S. A. Andronati Yu. A. Simonov I. G. Filippova M. Gdaniec 《Chemistry of Heterocyclic Compounds》2007,43(8):1029-1037
The condensation of 5-aryl-7-bromo-1,2-dihydro-3H-1,4-benzodiazepin-2-ones with aromatic aldehydes gives 5-aryl-3-arylidene-and
5-aryl-7-bromo-3-hetarylidene-1,2-dihydro-3H-1,4-benzodiazepin-2-ones. X-ray diffraction structural analysis yielded the molecular
and crystal structures of 7-bromo-3-(4′-methoxybenzylidene)-5-phenyl-1,2-dihydro-3H-1,4-diazepin-2-one and showed that this
compound has cis configuration. Radioligand analysis was used to study the affinity of these products toward central nervous
system and peripheral benzodiazepine receptors.
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Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1213–1225, August, 2007. 相似文献
7.
Armesto D Caballero O Ortiz MJ Agarrabeitia AR Martin-Fontecha M Torres MR 《The Journal of organic chemistry》2003,68(17):6661-6671
Triplet-sensitized irradiation of 2-aza-1,4-dienes affords N-cyclopropylimines via 2-aza-di-pi-methane (2-ADPM) rearrangement pathways. In the case of the pentaphenyl-substituted azadiene 1, irradiation leads to formation of cyclopropylimine 2 as well as N-vinylaziridine 3. The transformations represent the first examples of di-pi-methane rearrangement reactions that yield three-membered heterocyclic products. SET-sensitized irradiation of 2-aza-1,4-dienes, by using 9,10-dicyanoanthracene (DCA) as an electron-acceptor sensitizer and biphenyl as cosensitizer, brings about regioselective formation of N-vinylaziridines. Under these conditions, azadiene 1 also affords cyclopropylimine 37, resulting from an aryl-di-pi-methane rearrangement. This result demonstrates that di-pi-methane reactions can also take place via radical-cation intermediates. In some instances, imine and olefin centered cation-radical intermediates, generated by SET-sensitized irradiation, undergo alternative reactions to produce isoquinoline and benzoazepine products. 相似文献
8.
Rita Vaickelionienė Vytautas Mickevičius Gema Mikulskienė Maryna Stasevych Olena Komarovska-Porokhnyavets Volodymyr Novikov 《Research on Chemical Intermediates》2011,37(8):1009-1027
N′-(4-Oxo-1,4-dihydronaphthalen-1-ylidene)-1-phenyl-5-oxopyrrolidine-3-carbohydrazides and N′-(3-methyl-4-oxo-1,4-dihydronaphthalen-1-ylidene)-1-phenyl-5-oxopyrrolidine-3-carbohydrazides were synthesized by reactions
of 5-oxo-1-phenylpyrrolidine-3-carbohydrazides with 1,4-naphthoquinone or 2-methyl-1,4-naphthoquinone. The alkylated analogues
of the above products were obtained using ethyl iodide. The interaction of 5-oxo-1-phenylpyrrolidine-3-carbohydrazides with
2,3-dichloro-1,4-naphthoquinone was followed by formation of N′-(3-chloro-1,4-dioxo-1,4-dihydronaphthalen-2-yl)-1-phenyl-5-oxopyrrolidine-3-carbohydrazides. All these compounds were characterized
using 1H, 13C NMR, IR and mass spectra. Some of the new compounds were tested for the antimicrobial and antifungal activity. 相似文献
9.
Mandeep Thakur 《Tetrahedron》2008,64(22):5168-5173
1,4-Biradicals generated in the Norrish type-II reactions of 3-propargyloxy-2-arylchromones lead to cyclic products involving the 2-aryl group. The formation and distribution of products varied with the nature of 2-aryl group. 相似文献
10.
Ippolito Antonini Francesco Claudi Gloria Cristalli Mario Grifantini Sante Martelli 《Journal of heterocyclic chemistry》1980,17(1):181-185
The course of the thermal, acid-catalysed and iodide-catalysed decomposition of 2-amino-3-(2′,2′-dimethylaziridino)-1,4-naphthoquinone (III) was investigated. Thermal and iodide-catalysed decompositions gave mainly 2,3-diamino-1,4-naphthoquinone (VI) and 2-amino-3-(2′-methylallylamino)-1,4-naphthoquinone (V) together with low amounts of 2,2-dimethyl-1,2,3,4,5,10-hexahydrobenzo[g]quinoxaline (IV) and 2-isopropyl-1H-naphthoimid-azole-4,9-dione (VII). The acid catalysed isomerization of the aziridinonaphthoquinone III with halohydric acids or with acetic acid readily gave the opening of the aziridine ring; the corresponding salts of 2-amino-3-(2′-haloisobutylamino)-1,4-naphthoquinones (VIIIa-c) and 2-amino-3-(2′-acetoxyisobutylamino)-1,4-naphthoqunone (X) were formed by cleavage of the carbon-nitrogen bond at the substituted carbon atom. Hypotheses on the mechanism of these reactions are given. 相似文献
11.
Tsubogo T Saito S Seki K Yamashita Y Kobayashi S 《Journal of the American Chemical Society》2008,130(40):13321-13332
Catalytic asymmetric 1,4-addition and [3 + 2] cycloaddition reactions using chiral calcium species prepared from calcium isopropoxide and chiral bisoxazoline ligands have been developed. Glycine Schiff bases reacted with acrylic esters to afford 1,4-addition products, glutamic acid derivatives, in high yields with high enantioselectivities. During the investigation of the 1,4-addition reactions, we unexpectedly found that a [3 + 2] cycloaddition occurred in the reactions with crotonate derivatives, affording substituted pyrrolidine derivatives in high yields with high enantioselectivities. On the basis of this finding, we investigated asymmetric [3 + 2] cycloadditions, and it was revealed that several kinds of optically active substituted pyrrolidine derivatives containing contiguous stereogenic tertiary and quaternary carbon centers were obtained with high diastereo- and enantioselectivities. In addition, optically active pyrrolidine cores of hepatitis C virus RNA-dependent polymerase inhibitors and potential effective antiviral agents have been synthesized using this [3 + 2] cycloaddition reaction. NMR spectroscopic analysis and observation of nonamplification of enantioselectivity in nonlinear effect experiments suggested that a monomeric calcium species with an anionic ligand was formed as an active catalyst. A stepwise mechanism of the [3 + 2] cycloaddition, consisting of 1,4-addition and successive intramolecular Mannich-type reaction was suggested. Furthermore, modification of the Schiff base structure resulted in a modification of the reaction course from a [3 + 2] cycloaddition to a 1,4-addition, affording 3-substituted glutamic acid derivatives with high diasterero- and enantioselectivities. 相似文献
12.
A. L. Romanyuk O. P. Polishchuk B. L. Litvin N. I. Ganushchak 《Russian Journal of General Chemistry》2002,72(2):251-254
A series of 2-hydroxy-3-arylazo-1,4-naphthoquinones were prepared by coupling of 2-hydroxy-1,4-naphthoquinone with aryldiazonium chlorides. The reactivity of the products toward electrophilic and nucleophilic agents was studied. In reaction with o-phenylenediamine they give condensation products, the corresponding benzo[a]phenazines. 相似文献
13.
1,4-Nucleophilic addition reactions of 3-nitrothiochromone with indoles gave a number of novel trans-2-(indol-3-yl)-3-nitrothiochroman-4-ones in 36–89% yields. During the reactions, the thiopyrone ring underwent no opening. 相似文献
14.
Bradley SA Bresnan BJ Draper SM Geraghty NW Jeffares M McCabe T McMurry TB O'Brien JE 《Organic & biomolecular chemistry》2011,9(8):2959-2968
A series of 6-alkenyl-3-phenylcyclohex-2-enones has been synthesised and the structures of the products obtained from them on irradiation have been determined. The 6-propenyl compounds afforded a tricyclic 'parallel' [2 + 2] cycloaddition product and a bicyclic enone resulting from hydrogen abstraction in the biradical intermediate. The 6-butenyl and 6-pentenyl analogues gave 'crossed' cycloaddition products only. Although the regiochemistry of these cycloaddition reactions cannot be explained in terms of the 'rule of five', it is compatible with the concept of 'biradical conformation control' which is based on a consideration of the energy and structure of the possible 1,4-biradical intermediates. 相似文献
15.
1, 5, 6, 7-Tetrahydro-2H-[1, 4]diazepin-5, 7-diones from Malonimides and 3-Dimethylamino-2, 2-dimethyl-2H-azirine Reaction of the aminoazirine 1 with malonimides of type 7 in 2-propanol at room temperature leads to the 1,4-diazepine derivatives of type 9 (Scheme 3). The structure of 6, 6-diethyl-3-dimethylamino-2,2-dimethyl-1,5,6, 7-tetrahydro-2H- [1,4] diazepin-5, 7-dione ( 9a ) has been proved by single crystal X-ray analysis (Chapter 4). Reduction of the 7-membered heterocycle 9a with sodium borohydride yields the perhydro-[1,4]diazepin-5, 7-dione 10 , while 9a in ethanol at 60° undergoes a ring contraction to the 4 H-imidazole derivative 11a (Scheme 4): Mechanisms of these two reactions are discussed in comparison with previously reported reactions (Chapter 5). 相似文献
16.
L. M. Gornostaev Yu. G. Khalyavina N. P. Gritsan Yu. V. Gatilov 《Russian Journal of Organic Chemistry》2013,49(9):1307-1312
2-Arylamino-3-chloro-5,8-dihydroxy-1,4-naphthoquinones reacted with acetic anhydride and benzoyl chloride in pyridine to give in succession the corresponding O-acyl derivatives at both hydroxy groups. The primary acylation products were 8-acyloxy-2-arylamino-3-chloro-5-hydroxy-1,4-naphthoquinones. 相似文献
17.
The regioselectivity involved in the gas-phase hydride reduction of α,β-unsaturated carbonyl compounds by pentacoordinate silicon hydride ions is investigated. The kinetics and product distributions of the reactions of acrolein, methyl vinyl ketone and cyclohex-2-enone with monoalkoxysiliconate ions of the general composition RSiH3(OR′)? were examined with the flowing afterglow–triple quadrupole technique. All three substrates react by hydride transfer and by formation of a siliconate adduct in which hydride reduction of the organic reactant has occurred. The structures of these adducts and the hydride transfer products were identified by various tandem mass spectrometric protocols, including analysis of competitive collision-induced dissociation (CID) reactions and comparisons of CID spectra obtained from reference ions with known structures. 1,4-Reduction forming an enolate ion product is found to be the dominant or exclusive process with all three substrates, i.e. acrolein (70 ± 5%), methyl vinyl ketone (72 ± 5%) and cyclohex-2-enone (100%). Comparisons are made between these gas-phase results and the regioselectivity reported for analogous condensed-phase reactions. The observed behavior is discussed in terms of the reaction thermochemistry. 相似文献
18.
Johannes Reisch Marlies Iding Cyril Odianose Usifoh 《Journal of heterocyclic chemistry》1993,30(4):1117-1120
Quinazoline-2,4(1H,3H)-dione ( 1 ) was reacted with 1,4-dibromo-2-methylbut-2-ene ( 2 ) to give two dialkylated products and two monoalkylated products. The reaction of 6,7-dimethoxyquinazoline-2,4(1H,3H)-dione ( 8 ) with 1,4-dibromo-2-methylbut-2-ene ( 2 ) resulted in the formation of three dialkylated products. 相似文献
19.
Y Yoshitake K Yamaguchi C Kai T Akiyama C Handa T Jikyo K Harano 《The Journal of organic chemistry》2001,66(26):8902-8911
The pericyclic reactions of 2,5-bis(methoxycarbonyl)-3,4-diphenylcyclopentadienone (1a) with both allylic and propargylic amines have been investigated. The reaction proceeded via initial formation of the 1,4 adducts followed by the ene cyclization and/or sequential pericyclic reactions depending upon the structures of the amines. The reaction of 1a with diallylamine (2a) gave the tetracyclic compound (3a). On the other hand, the reaction of 1a with 2-propynylamine (2c) gave exclusively the bicyclic compound (5c). In the reactions with the secondary 2-propynylamines (2d,e), the tetracyclic compounds (3d,e) were exclusively formed. The reactions of 1a with alpha-branched primary 1,1-dialkyl-2-propynylamines (2f,g) gave mixtures of 3- and 5-type compounds. The tetracyclic compounds 3 were formed from the intramolecular [4+2]pi cycloadditions of the [1,5]-sigmatropic rearrangement products of the 1,4 adducts of 1a and 2, followed by the [1,5]-sigmatropic rearrangement of hydrogen and dehydrogenation. The bicyclic compounds 5 were derived from the [2pi+2pi+2sigma] reaction of the 1,4 adducts of 1a and 2. The one-pot multistage sequential pericyclic reactions were discussed on the basis of the X-ray crystallographic structures and the MO calculation data. 相似文献
20.
The thermal reactions of 4-chloro-3-coumarinyl N,N-dialkyldithiocarbamates 2–4 and 3-nitro-4-coumarinyl N-phenyldithiocarbamate, 9 , afforded the novel heterocyclic systems, e.g. bis-6H-1-benzopyrano[4,3-b]1,4]dithiin, 7 , and bis-6H-1-benzopyrano[4,3-b][1,4]thiazine, 14. A possible mechanism of the formation of the reaction products is discussed. 相似文献