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1.
Abdelmalek Bouraiou Abdelmadjid Debache Salah Rhouati Ali Belfaitah Bertrand Carboni 《Journal of heterocyclic chemistry》2008,45(2):329-333
2.
《Tetrahedron》1988,44(5):1523-1534
Cycloadditions involving the 1,2-prototropic route and the decarboxylative route to azomethine ylides were studied with cyclopropyl substituents located on one or both carbon atoms of the azomethine ylides and in several instances in the dipolarophile. Cycloadducts were obtained in good yield with no evidence of biradical intermediates, i.e. no products arising from cyclopropyl radical ⇀ but-3-enyl radical rearrangements were detected. 相似文献
3.
The formation of thiadiazolidines 3a-c and dithiazolidines 4a-c and 5a-b from the title reactions has been studied in detail under a variety of conditions. On the basis of kinetic measurements, isomerization studies and cross experiments a mechanism is proposed involving path (b) (Scheme 1) as the first step, followed by a series of isomerizations as shown in Scheme 3 . 相似文献
4.
R. T. Pardasani P. Pardasani S. K. Yadav P. V. Bharatam 《Journal of heterocyclic chemistry》2003,40(4):557-563
1,3‐Dipolar cycloadditon of azomethine ylides with different dipolarophiles leads to the formation of novel heterocyclic spiro compounds having two or more chiral centers. The theoretical studies (HF/3–21G) on the 1,3‐dipolar cycloaddition reaction between ethene and azomethine ylide A4 derived from isatin and thaizolidine‐4‐carboxylic acid, indicates that the energy barrier for this addition is about ~ 8 kcal/mol higher than that in simplest azomethine ylide A1 . HF/3–21G studies on a series of azomethine ylides A2 and A3 suggested that the increased barrier is mainly due to stabilization of azomethine ylides arising from aromatic indol nucleus. Semi‐empirical studies indicate that the cycloaddition is streocontrolled as the transition states corresponding to only the stericlly allowed paths could be located on the potential energy surface. 相似文献
5.
Shambhu Nath Singh Sridhar Regati Abir Kumar Paul Mohosin Layek Sarva Jayaprakash K. Venkateshwara Reddy Girdhar Singh Deora Soumita Mukherjee Manojit Pal 《Tetrahedron letters》2013
CuI facilitated three-component reaction of isatin derivatives, l-proline and terminal alkynes containing an amide or ester functional group. The multi-component reaction (MCR) afforded a faster and practical synthesis of spirooxindole derivatives. A range of novel spirooxindoles were synthesized by using this straightforward and one-pot efficient methodology. A representative compound showed significant inhibition of PDE4B enzyme in vitro and good interactions with this protein in silico. 相似文献
6.
The azomethine N‐oxides ( 1 ) on reacting with N‐benzylmaleimide ( 2 ) provide a mixture of stereoisomers 2,3‐diphenyl‐5‐benzyl‐4H‐2,3,3a,5,6,6a‐hexahydropyrrolo[3,4‐d]isoxazole‐4,6–dione derivatives ( 3 ) in good yields. These isomers have been assigned cis and trans configurations ( 3‐A and 3‐B ) with respect to proton C3‐H on the azomethinic carbon on the basis of their PMR and H‐NMR COSY data. The ratio between cis and trans isomers has been found to be dependent on substituents present at ortho position of C‐phenyl aldehydic moiety. The salient feature of these 1,3‐dipolar cycloaddition reactions lies in that the benzylic protons on N‐benzyl moiety suffer gem coupling, indicating magnetic nonequivalence. J. Heterocyclic Chem.,, (2012). 相似文献
7.
Alan R. Katritzky Suoming Zhang Mingyi Wang Hartmuth C. Kolb Peter J. Steel 《Journal of heterocyclic chemistry》2002,39(4):759-765
1,3‐Dipolar cycloadditions of benzotriazole‐stabilized nitrile ylides with benzyl α,β‐unsaturated‐carboxy‐lates and aldehydes as dipolarophiles proceeded smoothly and efficiently to give polysubstituted pyrroles and oxazoles, respectively, in good yields. 相似文献
8.
Suresh Babu Meruva A. Raghunadh N. Anil Kumar U. K. Syam Kumar R. Vasu Dev P. K. Dubey 《Journal of heterocyclic chemistry》2011,48(3):540-548
A variety of 5‐aryl‐(20S)‐camptothecin derivatives were synthesized by the reaction of 5‐hydroxy‐(20S)‐camptothecin with aromatic hydrocarbons under Friedel‐Craft reaction conditions in moderate to good yield as diastereomeric pairs. The methodology was then extended for the synthesis of 5‐amido‐(20S)‐camptothecin derivatives by reacting 5‐hydroxy‐(20S)‐camptothecin with alkyl and aryl nitriles under Ritter type reaction conditions. The reaction is presumed to proceed through an iminium ion intermediate under Friedel Craft and Ritter type reaction condition, which is further trapped by nucleophile present in the reaction medium. J. Heterocyclic Chem., 00 , 00 (2011). 相似文献
9.
A simple and efficient method for the synthesis of novel spiropyrrolidines has been accomplished by regioselective 1,3‐dipolar cycloaddition reactions of an azomethine ylide generated by thermal‐ring opening of cis‐1‐cyclohexyl‐2‐phenyl‐3‐benzoyl aziridine with various (E)‐3‐arylidene‐4‐chromanones. The synthesis proceeds in good yield to afford novel spiropyrrolidines, 1‐cyclohexyl‐2‐phenyl‐3‐aryl‐5‐benzoylpyrrolidine‐spiro‐[4.3′]4′‐chromanones. The X‐ray crystal structure analysis of one of the products confirms its structure. Molecular orbital calculations were performed to investigate the regioselectivity of the cycloaddition process. © 1999 John Wiley & Sons, Inc. Heteroatom Chem 10: 500–507, 1999 相似文献
10.
11.
Shashikanth Ponnala Devi Prasad Sahu Rishi Kumar Prakas R. Maulik 《Journal of heterocyclic chemistry》2006,43(6):1635-1640
12.
Alexey M. Starosotnikov Maxim A. Bastrakov Sergey Yu. Pechenkin Margarita A. Leontieva Vadim V. Kachala Svyatoslav A. Shevelev 《Journal of heterocyclic chemistry》2011,48(4):824-828
The 1,3‐dipolar cycloaddition of unstabilized N‐methyl azomethine ylide to mononitro benzazoles was studied. Depending on the nature of substituents and annelated azoles, the reaction affords previously unknown isoindole fused heterocyclic systems. The reactivity of the cycloadducts was examined. J. Heterocyclic Chem., (2011). 相似文献
13.
Kaushik Chanda Milan Ch. Dutta Enamul Karim Jai N. Vishwakarma 《Journal of heterocyclic chemistry》2004,41(4):627-631
1‐(Aralkyl/aryl)‐3‐(alkyyaralkyl)‐5‐aroyl‐1,2,3,4‐tetrahydropyrimidines ( 2a‐c ) have been synthesized by dethiomethylation of 5‐aroyl‐6‐methylthio‐1,2,3,4‐tetrahydropyrimidines ( 1a‐c ). An alternative one‐pot synthetic strategy has been developed for the title compounds 2a‐t by the reaction of enaminones 3 with pri mary amine and formaldehyde in refluxing methanol in good yields. 相似文献
14.
A new family of chiral ferrocenyl P,S-ligands has been developed and successfully applied in a highly endo-selective catalytic asymmetric cycloaddition of azomethine ylides with various enones, including cyclic and acyclic α-enones. For cyclic α-enones, a [Cu(CH(3)CN)(4)]ClO(4)/(R(c),S(Fc))-2f complex catalyzed the cycloaddition to give the sole endo-cycloadducts in perfect enantioselectivities (normally 99% ee), while an AgOAc/(R(c),S(Fc))-2f catalytic system exhibited good endo/exo selectivities (endo/exo = 91/9 to 96/4) and high enantiocontrol (up to 98% ee) for acyclic α-enones. 相似文献
15.
2-Iminothiazole, an isoform of 2-aminothiazole, is a scaffold of synthetic and medicinal significance. We have reported an efficient method by which alkyl group of 2-alkyliminothiazoles is changed into other alkyl groups by isothiocyanates. In this article, a detailed mechanistic aspect, and the scopes and limitations were disclosed. All the reactions were carried out in toluene at 105 °C without any additive. The reaction is a reversible process and the equilibrium is determined by the reactivity of both reactants, in which the more electron-withdrawing alkyl or aryl groups at the 2-imino group or isothiocyanate showed higher reactivities. With this simple method, we effectively altered the alkyl group attached on the imine nitrogen. A synthetic problem in 2-iminothiazole chemistry, synthesis of amino acid-derived 2-iminothiazole was solved in a very simple manner. Using suitably designed 2-iminothiazole substrate, the electrophilic reactivity of various isothiocyanates could be empirically compared by this exchange reaction. Moreover, successful exchange reaction using isocyanates instead of isothiocyanates broadened the utility of this reaction. 相似文献
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17.
Rita Annunziata Mauro Cinquini Franco Cozzi Laura Raimondi Tullio Pilati 《Tetrahedron: Asymmetry》1991,2(12)
Enantiomerically pure (E)-γ-alkoxy-α,β-unsaturated esters were reacted with azomethine ylides obtained from glycine imines in the presence of LiBr and diazabicycloundecene (DBU), to afford tetrasubstituted pyrrolidines with complete regiocontrol and fair to excellent diastereoselectivity (only two diastereoisomers formed in up to 96: 4 diastereoisomeric ratio). The results are compared with those of other 1,3-dipolar cycloadditions, and the origin of stereocontrol is discussed. 相似文献
18.
Yukihiko Tomioka Chie Nagahiro Yumiko Nomura Hiroshi Maruoka 《Journal of heterocyclic chemistry》2003,40(1):121-127
Arylnitroso compounds 1–3 easily reacted with dimethyl bromomalonate to give the corresponding N‐aryl‐C,C‐dimethoxycarbonylnitrones ( 4–6 ). Treatment of C,C‐dimethoxycarbonyl‐N‐( 1‐naphthyl)nitrone ( 4 ) with acetylene compounds (dimethyl acetylenedicarboxylate, methyl 2‐butynoate or ethyl phenylpropiolate) caused 1,3‐dipolar cycloaddition to furnish the corresponding 1H‐benz[g]indolines ( 7a‐c ). In a similar manner, the reactions of nitrones 5 and 6 with acetylene compounds afforded the corresponding indolines 9a‐c and 11a‐c together with 4‐oxazolines 13a‐c and 14a‐c . 相似文献
19.
Nazar I. Rad Yuriy O. Teslenko Mykola D. Obushak Vasyl S. Matiychuk Roman Z. Lytvyn 《Journal of heterocyclic chemistry》2011,48(6):1371-1374
It has been shown that reactions 5‐substituted 2‐nitrothiophenes with arylacetonitriles in the presence of potassium hydroxide in methanol lead to the formation of the new [2‐(hydroxyimino)‐5‐R‐3(2H)‐thienylidene](aryl)acetonitriles. Under proposed reaction conditions, the formation of thieno[2,3‐c]isoxazole was not the case. J. Heterocyclic Chem., (2011). 相似文献
20.
Ahmet ener M. Kasim ener Ishak Bildmci Rahmi Kasimogullari Yunus Akamur 《Journal of heterocyclic chemistry》2002,39(5):869-875
The 1H‐pyrazole‐3‐carboxylic acid 2 , obtained from the furan‐2,3‐dione 1 and N‐Benzylidene‐N'‐(3‐nitrophenyl) hydrazine, was converted via reactions of its acid chloride 3 with various alcohols or N‐nucleo‐philes into the corresponding ester or amide derivatives 4 or 5 , respectively. Nitrile 6 and anilino‐pyrazole acid 7 derivatives of 2 were also obtained by dehydration of 5a in a mixture of SOCl2 with DMF and reduction of 2 with sodium polysulphide, respectively. While cyclocondensation reactions of 2 or 7 with phenyl hydrazine or hydrazine hydrate and 6 with only anhydrous hydrazine lead to derivatives of pyrazolo[3,4‐d]‐pyridazinone 8 and pyrazolo[3,4‐d]pyridazine amine 9 , respectivel. The reaction of 2 with 2‐hydrazinopyri‐dine provided hydrazono‐pyrazole acid derivative 10 , which was decarboxylated to give hydrazono‐pyra‐zole derivative 11 . Pyrazolo[4,3‐d]oxazinone 12 and 2‐quinolyl pyrazolo[3,4‐d]pyridazine 13 derivatives were also prepared by cyclocondensation reactions of 2 with hydroxylamine hydrochloride and 7 with acetaldehyde, respectively. 相似文献