- Reactivity of arylnitrile oxides and C-aroyl-N-phenylnitrones with 3-methylenedihydro-(3H)-furan-2-one and itaconic anhydride
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1,3-dipolar cycloaddition is a powerful route for the synthesis of five-membered heterocycles. The [3+2] cycloadditions of some α-methylene-γ-buryrolactones, namely 3-methylenedihydro-(3H)-furan-2-one (1) and itaconic anhydride (2) were studied. Their rea
- Roussel, Christophe,Ciamala, Kabula,Vebrel, Jo?l,Riche, Claude
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- 1,3-Cycloaddition reactions of 2-oxo-2H-[1]benzopyran-4-carbonitrile N- oxide. Synthesis of several new 4-substituted coumarins
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1,3-Cycloaddition reactions of new 2-oxo-2H-[1]benzopyran-4-carbonitrile N-oxide 2 with dipolarophiles, o-aminophenols and o-phenylenediamine resulted in 4-heterocyclic substituted coumarin derivatives. These derivatives are screened for antiinflammatory activity in vitro through their antiproteolytic activity, the interaction with 1,1-diphenyl-2-picrylhydrazyl and the ability to affect superoxide anion and to inhibit β-glucuronidase and soybean lipoxygenase.
- Nicolaides,Fylaktakidou,Litinas,Papageorgiou,Hadjipavlou-Litina
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- Reaction of polyfluorinated cyclohexa-2,4-dienones with aryl nitrile oxides
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Reaction of 1,3-dipolar cycloaddition of 6-chloropentafluorocyclohexa-2,4- dienone, 6-chloro-3-(pentafluorophenoxy)tetrafluorocyclohexa-2,4-dienone, and perfluoro-6-phenoxycyclohexa-2,4-dienone with aryl nitrile oxides proceeds highly stereoselectively at
- Kovtonyuk,Gatilov, Yu. V.
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Read Online
- 1,3-Dipolar cycloaddition reactions of acyl phosphonates with nitrile oxides: synthesis of phosphonate-containing dioxazole derivatives
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New phosphonate-containing five-membered heterocyclic dioxazole derivatives are synthesized via 1,3-dipolar cycloaddition reactions of nitrile oxides used as dipole with acyl phosphonates under basic conditions. Herein, acyl phosphonates take part in the
- Polat-Cakir, Sidika
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Read Online
- Regioselective [3+2] cycloaddition of nitrile oxides to 1Н-pyrrole-2,3-diones: synthesis of spiro[pyrroledioxazoles]
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[Figure not available: see fulltext.] 1,3-Dipolar cycloaddition of 1H-pyrrole-2,3-diones to nitrile oxides generated in situ from N-hydroxybenzimidoyl chlorides by the action of triethylamine proceeds regioselectively with the formation of 1,4,2-dioxazole
- Dmitriev, Maksim V.,Maslivets, Andrey N.,Moroz, Anna А.
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- One-Pot Regioselective Synthesis of 7-Bromo-2H-Benzo[b][1,4]Oxazin-3(4H)-One Linked Isoxazole Hybrids as Anti-Cancer Agents and Their Molecular Docking Studies
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Abstract: Regioselective synthesis of some novel 7-bromo-2H-benzo[b][1,4]oxazin-3(4H)-one linked isoxazole hybrids via copper(I) catalyzed one-pot reaction of various aromatic aldehydes with 7-bromo-4-(prop-2-yn-1-yl)-2H-benzo[b][1,4]oxazin-3(4H)-one was developed. The structures of the compounds that are synthesized are confirmed by 1H NMR, 13C NMR, and mass spectra. All the hybrids have been tested for their in vitro anticancer activity against four human cancer cell lines, including HeLa, MCF-7, A549, and PC3. Three of the compounds exhibited remarkable anticancer activity compared to standard drug etoposide. Molecular docking studies with EGFR also strengthened the in vitro anticancer activity.
- Karthik, B.,Kumar, A. Kannan,Nukala, Satheesh Kumar,Ravinder, M.,Swamy, T. Narasimha
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p. 1269 - 1275
(2021/12/23)
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- One-pot Synthesis of Some Novel Xanthine Derived Isoxazoles as Potent Antibacterial Agents
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In search of better antibacterial agents, a series of novel xanthine derived 3,5-disubstituted isoxazole derivatives were synthesized (3a-3j) in one-pot using 8-chloro-1,3-dimethyl-7-(prop-2-yn-1-yl)-1H-purine-2,6(3H,7H)-dione and aromatic aldehydes and f
- Vidya
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p. 551 - 557
(2021/02/02)
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- One Pot Synthesis and Antitumor Activity of Isoxazole-Pyrimido[4,5-c]isoquinolines
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Abstract: A number of new isoxazole coupled pyrimido[4,5-c]isoquinolines has been synthesized in good to excellent yields by the one pot method. The Cu(I)-catalyzed cycloaddition reaction between the terminal alkyne 4 and various aldehydes has led to nitr
- Venkatesh,Narsimha,Kumar,Reddy
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p. 2444 - 2450
(2021/02/16)
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- Cu(I)-Catalysis of One-Pot Synthesis of Some Novel Regioselective Isoxazole-Benzimidazole Hybrids and Their In Vitro Anti-Cancer Evaluation
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Regioselective synthesis of some novel isoxazole-benzimidazole hybrids in high yields via Cu(I)-catalyzed tandem one-pot reaction of aromatic aldehydes with 1-prop-2-ynylbenzimidazole is developed. Structures of the synthesized compounds are confirmed by
- Ashok Kumar,Shanmukha Kumar Jagarlapudib
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p. 2512 - 2515
(2020/02/25)
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- Novel access to 2-substituted quinolin-4-ones by nickel boride-mediated reductive ring transformation of 5-(2-nitrophenyl)isoxazoles
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Reductive ring transformation of 3-substituted 5-(2-nitrophenyl)isoxazoles, readily accessible via 1,3-dipolar cycloaddition of 2-ethinylnitrobenzene with nitrile oxides, opens a novel access to 2-substituted quinolin-4-ones. Nickel boride, generated in situ from nickel chloride and sodium borohydride, allows, via simultaneous reduction of the nitro group and reductive cleavage of the isoxazole ring, the one-step conversion into the target quinolin-4-ones. This protocol tolerates various functional groups, except olefins, and thus is complementary to the reductive ring transformation with iron/acetic acid, which predominantly tolerates olefins.
- Lohrer, Bernhard,Bracher, Franz
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supporting information
(2019/11/26)
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- Synthesis of novel spiro-isoxazoline and spiro-isoxazolidine derivatives of tomentosin
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A series of novel enantiomerically pure spiro-isoxazolidines and spiro-isoxazolines were synthesized regioselectively by 1,3-dipolar cycloaddition using respectively two dipoles, nitrones and nitrile oxides, on the exocyclic double bond of the B ring of t
- Zaki, Mohamed,Oukhrib, Abdelouahd,Akssira, Mohamed,Berteina-Raboin, Sabine
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p. 6523 - 6529
(2017/02/05)
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- Synthesis, antimalarial activity, and target binding of dibenzazepine-tethered isoxazolines
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Malaria, a complex and deadly parasitic infectious disease, is a huge public health problem in many endemic countries around the globe. The prevailing extensive resistance of malaria parasites to traditional drugs and emergence of resistance to the currently used frontline artemisinin-based chemotherapy calls for the development of new drugs. Towards this objective and since compounds containing the dibenzazepine moiety are effective in treating both gametocyte and asexual stage malaria parasites, including multi drug resistant parasites, a library of dibenzazepine tethered 3,5-disubstituted isoxazolines was synthesised via 1,3-dipolar cycloaddition reaction. An additional diversified group of dibenzazepine derivatives were accessed by Suzuki coupling of one of the above dibenzazepine derivatives with various organoboronic acids. All compounds were structurally characterized and were evaluated for their antimalarial activity. They exhibited good to excellent inhibitory activity against the growth of drug-sensitive Plasmodium falciparum 3D7 strain with IC50 values ranging from 0.2 to 7.7 μM. About 50% of the compounds were either minimally or not toxic to human cell lines. Five of the compounds (6j, 6k, 8c, 8k and 8l) that highly inhibited the parasite growth were further assessed for antimalarial activity using an additional chloroquine-sensitive (D6) and two chloroquine-resistant (W2 and 7G8) P. falciparum strains. These compounds were effective against all four strains (3D7, D6, W2 and 7G8), exhibiting IC50 values of 0.1 to 1.75 μM. The dibenzazepines were identified to target the metalloamino-peptidase of parasites. Molecular docking and dynamics simulation studies were performed to understand the binding mode and binding strengths of the selected compounds with the enzyme. In agreement with their excellent antimalarial activity, the data suggested that the compounds can strongly bind to the active site of the enzyme.
- Vinay Kumar, Koravangala S.,Lingaraju, Gejjalagere S.,Bommegowda, Yadaganahalli K.,Vinayaka, Ajjampura C.,Bhat, Pritesh,Pradeepa Kumara, Challanayakanahally S.,Rangappa, Kanchugarakoppal S.,Gowda, D. Channe,Sadashiva, Maralinganadoddi P.
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p. 90408 - 90421
(2015/11/16)
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- Hypervalent iodine-catalyzed cycloaddition of nitrile oxides to alkenes
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A new and convenient method for preparation of isoxazolines was developed by a catalytic cycloaddition of nitrile oxides generated in situ from aldoximes to alkenes in the presence of a catalytic amount of iodobenzene. In this protocol, iodobenzene was fi
- Xiang, Changbin,Li, Tingting,Yan, Jie
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supporting information
p. 682 - 688
(2014/01/17)
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- Microwave-assisted synthesis of 3,5-disubstituted isoxazoles and evaluation of their anti-ageing activity
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One-pot uncatalysed microwave-assisted 1,3-dipolar cycloaddition reactions between in situ generated nitrile oxides and alkynes bearing protected antioxidant substituents, were regioselectively afforded 3,5-disubstituted isoxazoles. The yields were modera
- Koufaki, Maria,Fotopoulou, Theano,Kapetanou, Marianna,Heropoulos, Georgios A.,Gonos, Efstathios S.,Chondrogianni, Niki
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p. 508 - 515
(2014/07/21)
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- Synthesis of 2-(2-methyltetrazol-5-yl)-2,2-dinitroacetonitrile and its reaction with substituted nitrile N-oxides
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A procedure of synthesis of 2-(2-methyltetrazol-5-yl)-2,2- dinitroacetonitrile has been developed and its reaction with substituted nitrile N-oxides has been investigated, proceeding by the mechanism of 1,3-dipolar cycloaddition and affording 2-methyl-5-[(1,2,4-oxadiazol-5-yl)(dinitro)methyl]- 2H-tetrazoles. The latter react with KOH in ethanol forming the potassium salt of 2-methyltetrazol-5-yldinitromethane and substituted 5-hydroxy-1,2,4- oxadiazoles.
- Abdelrakhim,Tyrkov,Yurtaeva
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p. 280 - 284
(2014/04/17)
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- Regioselective synthesis of isoxazole-mercaptobenzimidazole hybrids and their in vivo analgesic and anti-inflammatory activity studies
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Regioselective synthesis of isoxazole-mercaptobenzimidazole hybrids and their efficiency in in vivo analgesic and anti-inflammatory activity was described. A comparison of structure-activity relationship for there compounds was also emphasized.
- Kankala, Shravankumar,Kankala, Ranjith Kumar,Gundepaka, Prasad,Thota, Niranjan,Nerella, Srinivas,Gangula, Mohan Rao,Guguloth, Hanmanthu,Kagga, Mukkanti,Vadde, Ravinder,Vasam, Chandra Sekhar
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supporting information
p. 1306 - 1309
(2013/03/14)
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- Synthesis of fluorine-containing 1,4-dioxa-2-azaspiro-[4.5]deca-2,6,9- trienes by reaction of polyfluorinated cyclohexa-2,5-dienones with nitrile oxides
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4-Pentafluorophenoxy-, 4-nitro-, and 4-chloropentafluorocyclohexa-2,5-dien- 1-ones and 3,4,5-tris-(pentafluorophenoxy)trifluorocyclohexa-2,5-dien-1-one react with some benzonitrile and acetonitrile oxides exclusively at the carbonyl group, leading to the formation of mixtures of diastereoisomeric fluorinated 1,4-dioxa-2-azaspiro[4.5]deca-2,6,9-trienes in good yield.
- Kovtonyuk, V. N.,Kobrina, L. S.,Gatilov, Yu. V.
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p. 783 - 787,5
(2020/08/31)
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- Discovery, synthesis, and biological evaluation of a novel group of selective inhibitors of filoviral entry
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Herein, we report the development of an antifiloviral screening system, based on a pseudotyping strategy, and its application in the discovery of a novel group of small molecules that selectively inhibit the Ebola and Marburg glycoprotein (GP)-mediated infection of human cells. Using Ebola Zaire GP-pseudotyped HIV particles bearing a luciferase reporter gene and 293T cells, a library of 237 small molecules was screened for inhibition of GP-mediated viral entry. From this assay, lead compound 8a was identified as a selective inhibitor of filoviral entry with an IC50 of 30 μM. To analyze functional group requirements for efficacy, a structure-activity relationship analysis of this 3,5-disubstituted isoxazole was then conducted with 56 isoxazole and triazole derivatives prepared using "click" chemistry. This study revealed that while the isoxazole ring can be replaced by a triazole system, the 5-(diethylamino)acetamido substituent found in 8a is required for inhibition of viral-cell entry. Variation of the 3-aryl substituent provided a number of more potent antiviral agents with IC50 values ranging to 2.5 μM. Lead compound 8a and three of its derivatives were also found to block the Marburg glycoprotein (GP)-mediated infection of human cells.
- Yermolina, Maria V.,Wang, Jizhen,Caffrey, Michael,Rong, Lijun L.,Wardrop, Duncan J.
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experimental part
p. 765 - 781
(2011/04/15)
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- Design and synthesis of spiro derivatives of parthenin as novel anti-cancer agents
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Several novel spiro derivatives of parthenin (1) have been synthesized by the dipolar cycloaddition using various dipoles viz; benzonitrile oxides, nitrones and azides with exocyclic double bond of C ring (α-methylene- γ-butyrolactone). Majority of the compounds exhibited improved anti-cancer activity compared to the parthenin, when screened for their in vitro cytotoxicity against three human cancer cell lines viz., SW-620, DU-145 and PC-3. In vivo screening of select analog revealed improved anti-cancer activity with low mammalian toxicity as compared to parthenin. The results of the cytotoxicity pattern of these derivatives reveals the SAR of these sesquiterpinoid lactones and possible role of α,β-unsaturated ketone of parthenin in inhibiting NF-kB. A mechanistic correlation of anti-cancer activity along with in vivo and western blotting experiments has been described.
- Reddy, Doma Mahendhar,Qazi, Naveed A.,Sawant, Sanghpal D.,Bandey, Abid H.,Srinivas, Jada,Shankar, Mannepalli,Singh, Shashank K.,Verma, Monika,Chashoo, Gousia,Saxena, Arpita,Mondhe, Dilip,Saxena, Ajit K.,Sethi,Taneja, Subhash C.,Qazi, Gulam N.,Sampath Kumar
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body text
p. 3210 - 3217
(2011/07/31)
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- N-Heterocyclic carbene-catalyzed 1,3-dipolar cycloaddition reactions: A facile synthesis of 3,5-di- and 3,4,5-trisubstituted isoxazoles
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A first example of organo-N-heterocyclic carbene (NHC) catalyzed click-type fast 1,3-dipolar cycloaddition of nitrile oxides with alkynes was developed for the regioselective synthesis of 3,5-di- and 3,4,5-trisubstituted isoxazoles. Triethylamine (Et
- Kankala, Shravankumar,Vadde, Ravinder,Vasam, Chandra Sekhar
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p. 7869 - 7876
(2011/12/05)
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- A novel synthesis of N-unsubstituted β-enamino thioesters from 3-arylisoxazoles and 3-aryl-5-phenylthio-2-isoxazolines
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A novel procedure for the synthesis of N-unsubstituted β-enamino thioesters, (Z)-S-phenyl 3-amino-3-arylprop-2-enethioates, from 3-arylisoxazoles or 3-aryl-5-phenylthio-2-isoxazolines is described and a plausible mechanism for the reaction is proposed. Some examples of conversion of one β-enamino thioester [(Z)-S-phenyl 3-amino-3-phenylprop-2-enethioate] into N-unsubstituted β-enaminoacyl derivatives (β-enamino esters, β-enamino amides, and β-keto amides) are also reported. Georg Thieme Verlag Stuttgart - New York.
- Vitale, Paola,Di Nunno, Leonardo,Scilimati, Antonio
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experimental part
p. 3195 - 3203
(2010/10/21)
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- Synthesis and pharmacological evaluation of 1,3,4-oxadiazole bearing bis(heterocycle) derivatives as anti-inflammatory and analgesic agents
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A series of novel ether-linked bis(heterocycle)s have been synthesized via [3 + 2]-cycloaddition reaction of nitrile oxide with allyl alcohol followed by intramolecular 1,3-diploar cycloaddition reaction of nitrile imine with carbonyl group. All the newly
- Jayashankar,Lokanath Rai,Baskaran,Sathish
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experimental part
p. 3898 - 3902
(2009/12/09)
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- Enantioselective 1,3-dipolar cycloaddition reactions using chiral lanthanide catalysts
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(Chemical Equation Presented) Regio- and stereoselective 1,3-dipolar cycloaddition of nitrile oxides to internal 2-pentenols, α,β- unsaturated esters and amides catalyzed by R-(+) BINOL-lanthanide complexes affords corresponding 3-aryl-2-isoxazolines with
- Golebiewski, W. Marek,Gucma, Miroslaw
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experimental part
p. 1687 - 1693
(2009/09/06)
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- Effect of the aryl group substituent in the dimerization of 3-arylisoxazoles to syn 2,6-diaryl-3,7-diazatricyclo[4.2.0.02,5]octan-4,8-diones induced by LDA
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3-Arylisoxazoles react with LDA in THF at 0 °C affording syn-2,6-diaryl-3,7-diazatricyclo[4.2.0.02,5]octan-4,8-diones (bis-azetidinones), via stereoselective dimerization of an azetinone anion intermediate. A?fragmentation reaction affording arylnitriles may compete with electronic and steric effects of the substituent present in the aryl group being pivotal in determining the outcome of this reaction. An interesting behaviour with LDA of arylnitriles arising from the fragmentation reaction of some 3-arylisoxazoles was also observed. N,N-Diisopropylaminobenzonitriles were in fact formed (plausibly via a benzyne mechanism) from 3-(4-chlorophenyl)isoxazole and 3-(2-chlorophenyl)isoxazole, whereas 3-(2-methylphenyl)isoquinolin-1-amine was isolated starting from 3-(2-methylphenyl)isoxazole and LDA.
- Di Nunno, Leonardo,Vitale, Paola,Scilimati, Antonio
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experimental part
p. 11198 - 11204
(2009/04/11)
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- Chiral ruthenium Lewis acid-catalyzed nitrile oxide cycloadditions
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The synthesis of the chiral ligand (R,R)-BIPHOP-F is detailed. Its coordination to a cationic cyclopentadienyl ruthenium fragment generates [Ru (acetone)(R,R)-BIPHOP-F)Cp][SbF6], a transition metal Lewis acid that catalyzes the [3+2] dipolar cy
- Brinkmann, Yasmin,Madhushaw, Reniguntala J.,Jazzar, Rodolphe,Bernardinelli, Gerald,Kündig, E. Peter
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p. 8413 - 8419
(2008/02/08)
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- Stereoselective dimerization of 3-arylisoxazoles to cage-shaped bis-β-lactams syn 2,6-diaryl-3,7-diazatricyclo[4.2.0.02,5]octan-4,8-diones induced by hindered lithium amides
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3-Arylisoxazoles react with hindered lithium amides giving syn 2,6-diaryl-3,7-diazatricyclo[4.2.0.02,5]octan-4,8-diones in good to fair yields. Stereochemistry of the so-obtained cage-shaped bis-β-lactams was assigned by X-ray diffraction analysis. Concerning the mechanism of formation of such hitherto unknown molecules, dimerization of an azetinone anion intermediate stereoselectively induced by Li+ chelation is suggested.
- Di Nunno, Leonardo,Vitale, Paola,Scilimati, Antonio,Simone, Laura,Capitelli, Francesco
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p. 12388 - 12395
(2008/03/13)
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- Anionic domino C-O-heterocyclization approach for the synthesis of 5-vinyl isoxazolines
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5-Vinyl isoxazolines were isolated in high yields through domino nucleophilic addition-anionic C-O-heterocyclization, when allyl organometallics derived from trans-1,4-dihalobutene were reacted with nitrile oxides. Georg Thieme Verlag Stuttgart.
- Qazi, Naveed Ahmed,Singh, Parvinder Pal,Jan, Sumira,Kumar, H. M. Sampath
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p. 1449 - 1451
(2008/02/13)
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- Reaction of allenylmagnesium and allenylindium bromides with nitrile oxides: synthesis of novel 5-butynyl- and 5-methylisoxazoles
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5-Butynylisoxazoles were obtained in high yields through a domino addition, C-O heterocyclization involving allenylmagnesium bromide and benzonitrile oxide in dry THF, in which the corresponding 5-methylisoxazoles were isolated in trace amounts. However, when the reactions were attempted in aqueous media using allenylindium bromide, 5-methylisoxazoles were formed as the sole products in high yields.
- Sampath Kumar,Singh, Parvinder Pal,Shafi, Syed,Reddy, Pitta Bhaskar,Shravankumar, Kankala,Reddy, Doma Mahender
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p. 887 - 890
(2007/10/03)
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- One-pot copper(I)-catalyzed synthesis of 3,5-disubstituted isoxazoles
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3,5-Disubstituted isoxazoles are obtained in good yields by a convenient one-pot, three-step procedure utilizing a regioselective copper(I)-catalyzed cycloaddition reaction between in situ generated nitrile oxides and terminal acetylenes. Most functional
- Hansen, Trond V.,Wu, Peng,Fokin, Valery V.
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p. 7761 - 7764
(2007/10/03)
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- One-Pot Synthesis of 3-Substituted Isoxazoles from Phenyl Vinylic Selenide
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Phenyl vinylic selenide was adopted for 1,3-dipolar cycloaddition to nitrile oxides and subsequent oxidation-elimination furnished 3-substituted isoxazoles with good yields in a one-pot, two-step transformation.
- Sheng, Shou-Ri,Liu, Xiao-Ling,Xu, Qu,Song, Cai-Sheng
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p. 2763 - 2764
(2007/10/03)
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- Stereoselective synthesis of alkynyl C-2-deoxy-β-D-ribofuranosides via intramolecular Nicholas reaction: A versatile building block for nonnatural C-nucleosides
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Figure presented The reaction of 3,5-di-O-benzyl-2-deoxy-D-ribofuranose with various alkynyllithium reagents afforded diastereomeric mixtures of the corresponding ring-opened alkynyldiols. The resulting diastereomeric mixtures were successively treated wi
- Takase, Masayoshi,Morikawa, Tomoyuki,Abe, Hajime,Inouye, Masahiko
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p. 625 - 628
(2007/10/03)
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- A novel synthesis of isoxazoles via 1,3-dipolar cycloaddition of nitrile oxides to acetyl acetone
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Nitrile oxides (2) isolated from the oxidative dehydrogenation of aldoximes (1) by chloramines-T react with acetyl acetone (3) to afford 4-acetyl-3-aryl-5-methyl isoxazoles (5) in good yield. All new compounds were characterized by IR, 1H NMR,
- Umesha,Kumar, K. Ajay,Rai, K. M. Lokanatha
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p. 1841 - 1846
(2007/10/03)
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- Diastereoselective [3+2] cycloadditions of a camphor-derived chiral N- acryloylhydrazide with nitrile oxides: The preparation of optically pure δ2-isoxazolines
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Reaction of a novel chiral N-acryloylhydrazide with various nitrile oxides proceeded smoothly to afford the cycloadduct with high diastereoselectivity (99:1). The auxiliary can be easily removed from the cycloadducts under mild conditions. (C) 2000 Elsevier Science Ltd.
- Yang, Kung-Shuo,Lain, Jung-Chaing,Lin, Chun-Hui,Chen, Kwunmin
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p. 1453 - 1456
(2007/10/03)
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- Intermolecular 1,3-dipolar cycloadditions of preformed nitrile oxides with phenyl vinyl sulphone
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Dipolar cycloadditions of nitrile oxides 2, isolated from the oxidative dehydrogenation of aldoximes by chloramine-T, with vinyl sulphone 3 are discussed.
- Rai, K.M. Lokanatha,Hassner
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p. 467 - 472
(2007/10/03)
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- Intermodular 1,3-dipolar cycloaddition of nitrite oxides with vinyl acetate and acrylonitrile
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Reaction of several nitrile oxides 2, isolated from the oxidative dehydrogenation of aldoximes by chloramine-T, with vinyl acetate and acrylonitrile proceeds in better yield than if the nitrile oxides are generated in situ. Solvent effects are also consid
- Lokanatha Rai,Hassner, Alfred
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p. 242 - 245
(2007/10/03)
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- The 1,3-dipolar cycloadditions of nitrile oxides and nitrile imines to alkyl dicyanoacetates
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The readily available alkyl dicyanoacetates 1 reacted with the 1,3-dipolar reagents arenecarbonitrile oxides 2′ and arenecarbonitrile imines 5′ to afford 1,2,4-oxadiazol and 1,2,4-triazol derivatives. The arenecarbonitrile oxides 2′ with electron-donating
- Neidlein, Richard,Sui, Zhihua
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p. 501 - 507
(2007/10/02)
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- Cycloadditions, 18: 5-Aminoisoxazoles by Cycloaddition of Nitrile Oxides to Ynamines
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Ten differently substituted ynamines 1a-j react with five nitrile oxides 3a-e to give the 5-aminoisoxazoles 4a-z.The stannyl-substituted ynamine 1k furnishes the same compounds (e.g. 4a-d) by reaction with the hydroximoyl chlorides 2a-d.Two representatives of 4 - b and p - can be transformed into the corresponding 1-azirine-3-carboxamides 6a and b.
- Himbert, Gerhard,Kuhn, Hildegard,Barz, Michael
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p. 403 - 407
(2007/10/02)
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- SITE SELECTIVITY IN THE REACTIONS OF 1,3-DIPOLES WITH NORBORNADIENE DERIVATIVES
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The cycloadditions of arylazides, benzonitrile oxides and diphenylnitrile imine to norbornadiene derivatives 1a-c showed varying degree of site- and stereo-selectivity.With dipolarophile 1a arylazides and benzonitrile oxides attack, preferentially, the electron-poor tetrasubstituted double bond, while in the case of 1b and 1c is the substituted double bond which enters the cycloaddition.By contrast, 2-diazopropane and C-phenyl-N-methylnitrone react with the sole tetrasubstituted double bond of 1a-c in stereo- and site-specific cycloadditions.The quantitative evaluation of the two possible reaction paths was performed by glc analysis.The compounds detected were those arising from Diels-Alder cycloreversions of the thermally labile intermediate adducts 2 and 3 (Scheme 1).The results were rationalized on the basis of a qualitative perturbation treatment which considers frontier orbital interactions only.
- Cristina, D.,Amici, M. De,Micheli, C. De,Gandolfi, R.
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p. 1349 - 1357
(2007/10/02)
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- SYNTHESIS AND PROPERTIES OF AZOLS AND THEIR DERIVATIVES. PART II. REACTION OF N-OXIDES OF AROMATIC NITRILES WITH UNCONJUGATED NITROOLEFINES AND SOME CONVERSION OF ADDUCT OBTAINED
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The reaction of 1,3-dipolar cycloaddition of 3-nitro-2-methylpropene-1, 3,3-dinitrobutene-1 or 3-nitropropene-1 with N-oxides of aromatic nitriles (RC6H4CN->O, R = H, m-NO2, p-NO2, p-CH3O) and likewise some chemical properties of 3-phenyl-5-nitromethyl
- Baranski, Andrzej,Shvekhgeimer, Genrikh A.,Kirillova, Natalia I.
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