Relevant bibliographies by topics / [4+21 Cycloaddition reaction

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  1. Journal articles
  2. Dissertations / Theses
  3. Book chapters
  4. Conference papers
  5. Reports

Academic literature on the topic '[4+21 Cycloaddition reaction'

Author: Grafiati
Published: 5 June 2025
Last updated: 1 August 2025

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Journal articles on the topic "[4+21 Cycloaddition reaction"

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Mausumi, Bandyopadhyay, Datta Kalyani, and Mal Dipakranjan. "Anionic [4+2]cycloaddition-Retro[4+2]cycloaddition strategy in the synthesis of psoralen and its isoster." Journal of Indian Chemical Society Vol. 76, Nov-Dec 1999 (1999): 551–56. https://doi.org/10.5281/zenodo.5862056.

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Department of Chemistry, Indian Institute of Technology, Kharagpur-721 302, India <em>Manuscript received 27 July 1999</em> Furan-1,4-dipolar agents 7 and 16e, prepared in few steps from commercially available furoates, have been annotated with bicyclopentadienone 2 to provide pentacyclic frameworks 8 and 17 respectively. Subsequent transformations of 8 and 17 through retro-Diels-Aider reaction and indenol-indanone rearrangement have furnished psoralen precursors 14 and 19. Similarly, oxaindacenone 23 has been prepared in good yield from 21.
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Cameron, Donald W., and Ross M. Heisey. "Reaction of Terminally Alkyl-Substituted Oxy Dienes with Tetracyanoethylene and Other Acceptors." Australian Journal of Chemistry 53, no. 3 (2000): 161. http://dx.doi.org/10.1071/ch00035.

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The 4,4-dimethyl-substituted oxy dienes (4), (19) and (20) did not undergo cycloaddition to 1,4-quinonoid dienophiles, for steric reasons, but all reacted with tetracyanoethylene to give [4+2]- or [2+2]-adducts. Unlike the 1-oxy diene (4), the 2- and 3-oxy systems (19) and (20) did not show hydrogen-transfer chemistry towards quinones. The individual components of isomeric pairs of dienes (8), (9) and (19), (21) were differentiated by differing reactivity towards cycloaddition.
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Suman, Kalyan Panja, Maiti Sourav, and Bandyopadhyay Chandrakanta. "Synthesis of 8,8' -(polymethylene-/ o-xylyl-dioxy)di(pyrano[ 4,3-b ]-1-benzopyran- 10H-10-one) and its conversion to corresponding diacrolein derivative." Journal of Indian Chemical Society Vol. 88, Oct 2011 (2011): 1577–80. https://doi.org/10.5281/zenodo.5790659.

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Department of Chemistry, Ramakrishna Mission Vivekananda Centenary College, Rahara, Kolkata-700 118, India <em>E-mail</em> : kantachandra@rediffmail.com <em>Manuscript received 29 November 2010, accepted 21 March 2011</em> 6,6&#39;-Tethered-di(4-oxo-4H-1-benzopyran-3-carboxaldehyde) undergoes inverse electron demand [4+ 2] cycloaddition reaction with ethoxyethene to produce endo-di(pyrano[4,3-b]-1-benzopyran), which produces diacrolein when treated with NaOMe in methanol.
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Regitz, Manfred, Klaus Urgast, and Gerhard Maas. "Phosphorverbindungen ungewöhnlicher Koordination, 3 [1] Vergleich des Cycloadditonsverhaltens von Diphenylketen und Triphenylphosphen / Phosphorus Compounds with Unusual Coordination, 3 [1] Comparison of the Cycloaddition Behaviour of Diphenylketene and Triphenylphosphene." Zeitschrift für Naturforschung B 40, no. 1 (1985): 67–76. http://dx.doi.org/10.1515/znb-1985-0115.

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Triphenylphosphene (3b), generated thermally or photochemically from 1b, undergoes olefination reaction with 4.5-benzotropone (6) to yield 1-(diphenylmethylen)-4.5-benzocycloheptatriene (9); the oxaphosphetane 7b is assumed to be the intermediate of this reaction. In an analogous way, 4-pyrone (15) is transformed into 4-(diphenylmethylen)pyrane (16). Corresponding olefination behaviour is observed in the reactions of 6 and 15 with diphenylketene.In the reaction of tetracyclone (20) with diphenylketene (3a), the olefination sequence leads to the formation of (diphenylmethylen)tetraphenylcyclope
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Seitz, Gunther, and Johanna Siegl. "Synthese neuer Pyridin-C-nukleoside der 2 ,3 -Didesoxyribose durch „inverse“ [4+2]-Cycloaddition Synthesis of Novel Pyridine-C-nucleosides of 2,3-Dideoxyribose by „Inverse“ [4+2]-Cycloaddition." Zeitschrift für Naturforschung B 52, no. 7 (1997): 851–58. http://dx.doi.org/10.1515/znb-1997-0715.

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The anomeric imido esters 5 and 6, appropriate precursors for C-nucleoside synthesis, were prepared and utilized as heterodienophiles in a Diels-Alder reaction with inverse electron demand to yield the novel, protected 1.2.4-triazine C-nucleosides 8 and 9. They could be deprotected by treatment with 70% trifluoroacetic acid to furnish the free C-nucleosides 10 and 11. The triazine „aglycon“ of 8 contains an electron deficient diazadiene system, highly activated to react with various electron rich dienophiles such as enamines, enol ethers and several cyclic ketene acetals in an „inverse“ [4+2]-
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Susanta, K. Borthakur, Boruah Paran, and N. Goswami Birendra. "[4+2] Cycloaddition reaction: Synthesis and antifungal activities of 2-substituted 1,2,4-triazolo[3,2-c][1,3,5]thiadiazine-3,3-dioxides." Journal of Indian Chemical Society Vol. 90, Jul 2013 (2013): 1005–8. https://doi.org/10.5281/zenodo.5774794.

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Department of Chemistry, Arya Vidyapeeth College, P.O. Gopinath Nagar, Guwahati-781 016, Assam, India <em>E-mail</em> : skbthakur@yahoo.co.in Medicinal Aromatic and Economic Plant Division, Formerly of Synthetic Organic Chemistry Division, North East Institute of Science and Technology, Jorhat-785 006, Assam, India <em>Manuscript received online 06 August 2012, revised 09 August 2012, accepted 16 August 2012</em> 3-Benzylidineamino-1,2,4-triazole undergoes [4+2] cycloaddition reaction with sulfene resulting in good yield of [1,2,4]-triazolo[3,2-<em>c</em>][1,3,5]-thiadiazine-3,3-dioxide deriva
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Auner, Norbert, and Claus-Rüdiger Heikenwälder. "Silaheterocyclen, XXXIII [1, 2]: Cycloadditions-Reaktionen des 1.1-Dichlor-2-neopentyIsilaethens mit Pentafulvenen / Silaheterocycles, XXXIII [1, 2]: C y clo ad d itio n Reactions of 1.1-Dichloro-2 -neopentylsilene with Pentafulvenes." Zeitschrift für Naturforschung B 52, no. 4 (1997): 500–514. http://dx.doi.org/10.1515/znb-1997-0412.

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The reaction between in situ formed 1.1-dichloro-2-neopentyl-1-silene, Cl2Si=CHCH2tBu (2), and 1,1-dimethylpentafulvene (5) leads to the formation of exo/endo-isomeric [4+2] cycloadducts 9 and [2+2] stereoisomers 10 in good yields. NMR spectroscopic investigations of the product mixture prove the different modes of the silene cycloaddition reactions ([4+2] vs [2+2] addition).Treatment of 9 and 10 with LiAlH4 and LiMe yield the stereo- and regioisomeric derivatives (LiAlH4: 16, 17: MeLi: 18. 19). whereas PhMgBr reacts with 10 to give only the mono substitution, the [4+2] compound 20. and the di
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Pyne, Stephen G., Javad Safaei-G., Karl Schafer, Abdollah Javidan, Brian W. Skelton, and Allan H. White. "Diastereoselective 1,3-Dipolar Cycloadditions and Michael Reactions of Azomethine Ylides to (2R)-3-Benzoyl-4-methylidene-2-phenyloxazolidin-5-one and (2S)-3-Benzoyl-2-t-butyl-4-methylideneoxazolidin-5-one." Australian Journal of Chemistry 51, no. 2 (1998): 137. http://dx.doi.org/10.1071/c97072.

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The 1,3-dipolar cycloaddition reactions of (1) and (11) with the azomethine ylides derived from N-benzylidene α-amino acid esters (2) proceed with good to high exo-diastereoselectivity giving the cycloadducts (4) and (12), respectively. The cycloaddition adducts can be converted to highly functionalised prolines (14), (15) and (17) in high enantiomeric purities. The Michael addition adducts of (1) and (11) with the azomethine ylides derived from the N-(disubstituted methylidene) α-amino acid esters (18), (19) and (33) allow for a practical synthesis of all four stereoisomers of 4-benzamidopyro
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Collins, DJ, TC Hughes, and WM Johnson. "Regiospecific Syntheses of the Monomethylated 3-Phenyldihydro-1,2,4-triazin-6(1H)-ones." Australian Journal of Chemistry 49, no. 4 (1996): 463. http://dx.doi.org/10.1071/ch9960463.

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Unambiguous syntheses of four unreported monomethylated derivatives of 3-phenyldihydro-1,2,4-triazin-6(1H)-ones, namely, the 1-methyl (2), 2-methyl (3), 4-methyl (4) and the imidic O-methyl derivative (5), are described. Regioselectivity was achieved for the synthesis of (2) by addition of ethyl glycinate to the 1,3-dipolar nitrile imine derived from N- methylbenzohydrazonoyl bromide hydrobromide (8). The key step for the synthesis of (3) was addition of benzyl 3-methylcarbazate (14) to ethyl N-[ chloro (phenyl) methylene ] glycinate (15b). The 4-methyl compound (4) was prepared by cycloadditi
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Seitz, Gunther, та Jens Lachmann. "Synthese neuer Pyridin-, Pyrindin- bzw. Isochinolin-substituierter α- und β-C-Nukleoside der 2-Desoxy-D-ribose / Synthesis of Novel Pyridine-, Pyrindine- and Isoquinoline-Substituted α- and β-C-Nucleosides of 2-Deoxy-D-ribose". Zeitschrift für Naturforschung B 54, № 4 (1999): 549–58. http://dx.doi.org/10.1515/znb-1999-0420.

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The novel imido esters of 2-deoxy-α- and -β-D-ribose 8 and 9 have been synthesized and successfully transformed to the protected 1,2,4-triazine-C -nucleosides 11 and 12 using an inverse type Diels-Alder reaction with the 1,2,4,5-tetrazine 10. The electron deficient diazadiene system of both C -nucleosides 11 and 12 proved to be highly reactive in a consecutive [4 + 2] cycloaddition with inverse electron demand towards several electron rich dienophiles yielding after successful deprotection the novel pyridine-, pyrindine- and isoquinoline-C-nucleosides 15, 18 and 21 of 2 -deoxy-α-D-ribose and 2
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Dissertations / Theses on the topic "[4+21 Cycloaddition reaction"

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MacNevin, Christopher J. "Reactivity of substituted 4-Pyridones in normal and inverse demand Diels-Alder cycloaddition /." Electronic version (PDF), 2003. http://dl.uncw.edu/etd/2003/macnevinc/christophermacnevin.pdf.

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Mansell, Howard Langham. "Synthetic studies towards the Prelog-Djerassi lactone and anatoxin-a via products of the [4+3] cycloaddition reaction." Thesis, University of Reading, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.262642.

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Chabour, Ihssene. "1,3-Dipolar cycloadditions using catalysts with double chirality and novel multicomponent [4+2] processes." Doctoral thesis, Universidad de Alicante, 2021. http://hdl.handle.net/10045/114674.

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In this thesis, different cycloaddition reactions, such as the enantioselective 1,3-dipolar-cycloaddition, which takes place between in situ generated stabilized azomethine ylides, and electrophilic alkenes, and the diastereoselective multicomponent reactions Amine-Aldehyde-Dienophile (AAD) or Phosphoramidate-Aldehyde-Dienophile (PAD) are described. In Chapter 1, an asymmetric 1,3-dipolar cycloaddition reaction involving an imino ester with tert-butyl acrylate was carried out using a silver(I) complex with double chirality, formed from a chiral phosphoramidite and chiral silver binolphosphate(
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Chen, Xi. "Réactivité d’alcynes fonctionnalisés en présence d’or et d’argent : réactions de cycloadditions énantiosélectives et d'oxofluoration." Thesis, Université Côte d'Azur, 2020. http://www.theses.fr/2020COAZ4065.

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Dans le contexte de «chimie verte», le développement de systèmes catalytiques efficaces, propres et réalisés dans des conditions douces est fondamental en chimie organique. Ce manuscrit est divisé en trois chapitres. Le premier chapitre relate la bibliographie concernant la chimie de l’or et de l’argent lorsqu’ils sont en présence d’alcynes. Les exemples les plus significatifs et les plus proches de notre étude sont présentés. La suite du manuscrit présente les réactions de cycloaddition des enynes-1,6 catalysées par des complexes d’or et d’argent. Le troisième chapitre repose sur l’associatio
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Guillam, Anne. "Synthèse et cycloadditions [4+2] des 1,4-dialkoxybutadiènes." Rouen, 1997. http://www.theses.fr/1997ROUES078.

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Ce travail présente une étude générale de la réactivité des 1,4-dialkoxybutadiènes dans les cycloadditions [4+2]. La synthèse des précurseurs diéniques nécessaires à cette étude, a dans un premier temps, été mise au point par élimination conjuguée sur des acétals ,-insaturés -in-saturés. Les diènes dioxygénés désirés ont ainsi été obtenus de façon efficace et stéréocontrôlée. Ils présentent la configuration 1Z,3E très majoritaire. Cette approche a également permis la synthèse de nouveaux systèmes bisdiéniques trioxygénés. Les diènes précédents ont ensuite été engagés dans des réactions de Diel
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ARYA-MORTEZAEI, FARIBA. "Reactivite thermique de n-alcenyliminocetenes." Reims, 1987. http://www.theses.fr/1987REIMS010.

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Les composes du titre conduisent a differentes cetones heterocycliques : desazepinones-4, des aza-3bicyclo (3. 2. 0)heptenes-2ones-7, des formyl-3 pyridinones-4. Les azobicyclohepotenones conduisent a des pyrrolidines et a des oxaziridines polycylcliques
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Ferroud, Clotilde. "Étude de la réaction de Diels-Adler intra et intermoléculaire sous haute pression : application à la synthèse stéréosélective d'alcaloïdes de l'indole du groupe des yohimbanes." Paris 6, 1986. http://www.theses.fr/1986PA066023.

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Le schéma de synthèse repose sur une unité bicyclique, précurseur direct des unités (d,e) du squelette pentacyclique. Cet intermédiaire est basé sur une réaction de Diels-Alder sous haute pression, utilisant la cycloaddition de diènes de structure donneur-accepteur 1,4 avec une lactone insaturée comme diénophile. La synthèse du système pentacyclique est exposée à partir de cet intermédiaire clé.
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文澎生. "Studies of the 1,3-dipolar cycloaddition reaction of 4-bromosydnone derivatives." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/46223547171261482374.

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碩士<br>靜宜大學<br>應用化學系<br>88<br>Sydnone is a typical mesoionic compound. It contains a five-membered of non-benzoid aromatic heterocyclic structure. Sydnone rings possess the unique electron distribution and reactions. The sydnone rings can be a precursor for the application in organic synthesis. Some of sydnone compounds demonstrate the biological activities, and have been investigated extensively. To clarify the mechanisms for the 1,3-dipolar cycloaddition reaction of sydnone compounds, the solution of sydnones and dicyclopentadiene in the m-xylene was refluxed. Three fused heterocy
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Chen, Po-Yuan, and 陳柏元. "Organocatalytic Enantioselective Domino Michael-Henry Reaction; Formal [3+2] Cycloaddition Reaction of 4-Hydroxycrotonaldehyde and Nitroolefin." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/95511756784223089480.

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碩士<br>國立中正大學<br>化學暨生物化學研究所<br>100<br>Asymmereic synthesis of highly functionalized cyclopentane ring, was carried out via organocatalyzed domino Michael-Henry reaction of 4-hydroxy crotonaldehyde and nitrostyrene at ambient temperature. However the cyclopentane adducts was obtained with high enantioselectivity and modrate diastereoselectivity. On the other hand the relative stereochemistry of major distereomer was determined by X-ray analysis.
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CHU, WEI-ZHANG, and 朱煒章. "The study of 1, 3-dipolar cycloaddition reaction of 3-arylsydnone-4-carbonitrile oxides and their properties." Thesis, 1987. http://ndltd.ncl.edu.tw/handle/53347898816217429334.

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Book chapters on the topic "[4+21 Cycloaddition reaction"

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Jones, Darin E., and Michael Harmata. "Application of The [4+3] Cycloaddition Reaction To The Synthesis of Natural Products." In Methods and Applications of Cycloaddition Reactions in Organic Syntheses. John Wiley & Sons, Inc., 2014. http://dx.doi.org/10.1002/9781118778173.ch19.

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Ogura, Akihiro, and Ken-ichi Takao. "Total Syntheses of (+)-Aquatolide and Related Humulanolides." In Modern Natural Product Synthesis. Springer Nature Singapore, 2024. http://dx.doi.org/10.1007/978-981-97-1619-7_13.

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AbstractHerein, the total syntheses of (+)-aquatolide, a humulane-derived sesquiterpenoid lactone, and five other related humulanolides are described. The key reactions in these syntheses are a cascade metathesis reaction of cyclobutenecarboxylate to construct a γ-butenolide with an unsaturated aldehyde side chain, an intramolecular Nozaki–Hiyama–Takai–Kishi reaction to form an all-trans-humulene lactone skeleton, and a biosynthesis-inspired [2 + 2] photocycloaddition to provide a bridged 5/5/4/8-ring system. A cycloaddition giving a 5/4/4/7-ring system was also found. In addition, biological
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Taber, Douglass F. "Diels–Alder Cycloaddition: Sarcandralactone A (Snyder), Pseudopterosin (−)-G-J Aglycone (Paddon-Row/Sherburn), IBIR-22 (Westwood), Muironolide A (Zakarian), Platencin (Banwell), Chatancin (Maimone)." In Organic Synthesis. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780190646165.003.0080.

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En route to sarcandralactone A 3, Scott A. Snyder of Scripps Florida effected (Angew. Chem. Int. Ed. 2015, 54, 7842) Diels–Alder cycloaddition of the activated enone 1 to the Danishefsky diene. On exposure to trifluoroacetic acid, the adduct was unraveled to the ene dione 2. Michael N. Paddon-Row of the University of New South Wales and Michael S. Sherburn of the Australian National University prepared (Nature Chem. 2015, 7, 82) the allene 4 in enantiomerically-pure form. Sequential cycloaddition with 5 followed by 6 gave an adduct that was decarbonylated to 7. Further cycloaddition with nitro
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Taber, Douglass. "Intermolecular and Intramolecular Diels-Alder Reactions: Platencin (Banwell), Platensimycin (Matsuo), (-)-Halenaquinone (Trauner), ( + )-Cassaine (Deslongchamps)." In Organic Synthesis. Oxford University Press, 2011. http://dx.doi.org/10.1093/oso/9780199764549.003.0079.

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José Barluenga of the Universidad de Oviedo described (Organic Lett. 2008, 10, 4469) a powerful route from lithiated arenes such as 1 to the benzocyclobutane 3, the immediate precursor to the powerful o-quinone methide Diels-Alder diene. Michael E. Jung of UCLA developed (Organic Lett. 2008, 10, 3647) a triflimide catalyst for the inverse electron demand coupling of the highly substituted diene 4 with the enol ether 5 to give 6 with high diastereocontrol. Joseph M. Fox of the University of Delaware showed (J. Org. Chem. 2008, 73, 4283) that the cyclopropene carboxylate 8 was a powerful and sel
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Taber, Douglass F. "Alkaloid Synthesis: (+)-Deoxoprosopinine (Krishna), Alkaloid (–)-205B (Micalizio), FR901483 (Huang), (+)-Ibophyllidine (Kwon), (–)-Lycoposerramine-S (Fukuyama), (±)-Crinine (Lautens)." In Organic Synthesis. Oxford University Press, 2015. http://dx.doi.org/10.1093/oso/9780190200794.003.0060.

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Palakodety Radha Krishna of the Indian Institute of Chemical Technology observed (Synlett 2012, 2814) high stereocontrol in the addition of allyltrimethylsilane to the cyclic imine derived from 1. The product piperidine 2 was carried onto (+)-deoxoprosopinine 3. Glenn C. Micalizio of Scripps Florida condensed (J. Am. Chem. Soc. 2012, 134, 15237) the amine 4 with 5. The ensuing intramolecular dipolar cycloaddition led to 6, which was carried onto the Dendrobates alkaloid (–)-205B 7. Pei-Qiang Huang of Xiamen University showed (Org. Lett. 2012, 14, 4834) that the quaternary center of 9 could be
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Taber, Douglass F. "C–O Ring Construction: (+)-Varitriol (Liu), (+)-Isatisine A (Panek), (+)-Herboxidiene/GEX1A (Ghosh), (–)-Englerin A (Chain), Platensimycin (Lear/Wright)." In Organic Synthesis. Oxford University Press, 2015. http://dx.doi.org/10.1093/oso/9780190200794.003.0050.

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En route to (+)-varitriol 4, Xue-Wei Liu of Nanyang Technological University coupled (Org. Lett. 2011, 13, 42) the glycosyl fluoride derived from 1 with the alkynyl fluoroborate salt 2 to give 3. James S. Panek of Boston University condensed (Org. Lett. 2011, 13, 502) the enantiomerically pure allyl silane 6 with the aldehyde 5 to give the tetrahydrofuran 7. Further elaboration led to (+)-isatisine A 8, the only alkaloid so far isolated from the roots and leaves of the traditional Asian folk medicine Isatis indigotica. Arun K. Ghosh of Purdue University effected (Org. Lett. 2011, 13, 66) oxida
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Lambert, Tristan H. "C–O Ring Formation." In Organic Synthesis. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780190646165.003.0044.

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The enantioselective bromocyclization of dicarbonyl 1 to form dihydrofuran 3 using thiocarbamate catalyst 2 was developed (Angew. Chem. Int. Ed. 2013, 52, 8597) by Ying-Yeung Yeung at the National University of Singapore. Access to dihydrofuran 5 from the cyclic boronic acid 4 and salicylaldehyde via a morpholine-mediated Petasis borono-Mannich reaction was reported (Org. Lett. 2013, 15, 5944) by Xian-Jin Yang at East China University of Science and Technology and Jun Yang at the Shanghai Institute of Organic Chemistry. Chiral phosphoric acid 7 was shown (Angew. Chem. Int. Ed. 2013, 52, 13593)
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Taber, Douglass F. "The Lee Synthesis of (−)-Crinipellin A." In Organic Synthesis. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780190646165.003.0098.

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The crinipellins are the only tetraquinane natural products. The enone crinipellins, including crinipellin A 3, have anticancer activity. Hee-Yoon Lee of the Korea Advanced Institute of Science and Technology (KAIST) envisioned (J. Am. Chem. Soc. 2014, 136, 10274) the assembly of 2 and thus 3 by the intramolecular dipolar cycloaddition of the diazoalkane derived from the tosylhydrazone 1. The initial cyclopentene was prepared from commercial 4 following the Williams procedure. Conjugate addition of the Grignard reagent 5 in the presence of TMS-Cl led to the silyl enol ether 6. Regeneration of
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Lambert, Tristan H. "Total Synthesis of C–O Ring-Containing Natural Products." In Organic Synthesis. Oxford University Press, 2015. http://dx.doi.org/10.1093/oso/9780190200794.003.0053.

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Scott A. Snyder at Columbia University demonstrated (J. Am. Chem. Soc. 2012, 134, 17714) that tetrahydrofuran 1 could be readily converted to oxocane 2 by treatment with the BDSB reagent developed in his laboratory. Reduction of 2 with DIBAL-H initiated a second ring closure by mesylate displacement to form the bicycle 3, which represented a formal total synthesis of laurefucin 4. Andrew L. Lawrence at the Australian National University found (Org. Lett. 2012, 14, 4537) that upon treatment with catalytic base, rengyolone 6, which was prepared in one pot from phenol 5, could be converted to the
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Taber, Douglass F. "Diels–Alder Cycloaddition: Nicolaioidesin B (Coster), Lycorine (Cho), Bucidirasin A (Nakada), Maoecrystal V (Thomson), Kuwanon J (Wulff/Lei), Vinigrol (Kaliappan)." In Organic Synthesis. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780190646165.003.0079.

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β-Ocimene 2 is an inexpensive Diels–Alder diene. En route to nicolaioidesin B 4, Mark J. Coster of Griffith University showed (Tetrahedron Lett. 2014, 55, 6864) that the Weinreb amide 1 added to the E isomer of 2 with high selectivity, to give 3. The alkaloid lycorine 8 is found throughout the Amaryllidaceae. Cheon-Gyu Cho of Hanyang University developed (Org. Lett. 2014, 16, 5718) a succinct route to 8 based on the use of the boryl styrene 5 as a Diels–Alder dienophile. Masahisa Nakada of Waseda University (Org. Lett. 2014, 16, 4734) prepared the enantiomerically-pure enone 9 by way of a bake
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Conference papers on the topic "[4+21 Cycloaddition reaction"

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Peña-Gallego, A., J. Rodríguez-Otero, and E. M. Cabaleiro-Lago. "The influence of BF3 on the reaction path of the [4 + 2] cycloaddition of vinylketene with formaldimine. A computational study." In The 10th International Electronic Conference on Synthetic Organic Chemistry. MDPI, 2006. http://dx.doi.org/10.3390/ecsoc-10-01455.

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Dinh Thanh, Nguyen, Do Son Hai, Cao Thi Le, Vu Thi Tuyet Thuy, and Do Tien Tung. "SYNTHESIS OF 2-AMINO-4H-PYRAN-3-CARBONITRILES ITS REACTION WITH CHLOROACETYL CHLORIDE." In The 21st International Electronic Conference on Synthetic Organic Chemistry. MDPI, 2017. http://dx.doi.org/10.3390/ecsoc-21-04770.

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Dinh Thanh, Nguyen, Le The Duan, Nguyen Thi Minh Nguyet, Le Thi Hoai, and Nguyen Thi Thu Ha. "STUDY ON REACTION OF SUBSTITUTED 4-METHYLQUINOLIN-2(1H)-ONES WITH SODIUM AZIDE." In The 21st International Electronic Conference on Synthetic Organic Chemistry. MDPI, 2017. http://dx.doi.org/10.3390/ecsoc-21-04771.

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Letourneau, J. E. "Effect of the warning signal on visual reaction time during recovery from general anesthesia." In OSA Annual Meeting. Optica Publishing Group, 1990. http://dx.doi.org/10.1364/oam.1990.tuy25.

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The purpose of the study was to measure recovery from general anesthesia. A group of 23 patients underwent surgery under general anesthesia with enflurane (N = 21) or halothane (N = 2). Anesthesia lasted 25120 min (mean = 52 min). Patients were measured before induction of anesthesia (trial 1) and 1, 2 and 3 h later (trials 2, 3, and 4). A control group (N = 23) underwent the same procedure. The instrument measured subjects' reaction times to a green light. A white light preceded the onset of the stimulus light. The foreperiod lasted successively 3, 2, and 4 s in each of three trials. Reaction
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Ocampo, Romina, Aldana Quiroga, Ignacio Costilla, et al. "Study of the effect of solvent and different Lewis acids in one pot multicomponent microwave assisted reaction for the chemoselective generation of 1.4-thiazepan-3-ones and 4-tiazolidinones." In The 21st International Electronic Conference on Synthetic Organic Chemistry. MDPI, 2017. http://dx.doi.org/10.3390/ecsoc-21-04792.

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Savikhin, S., and W. S. Struve. "Optical coherences in light-harvesting chlorosomes from green photosynthetic bacteria." In International Conference on Ultrafast Phenomena. Optica Publishing Group, 1996. http://dx.doi.org/10.1364/up.1996.tue.21.

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Chlorosomes are light-harvesting assemblies that are found in green photosynthetic bacteria [1]. The principal antenna in a chlorosome consists of ~104 bacteriochlorophyll (BChl) c, d, or e pigments, which give rise to a broad Qy electronic absorption band centered at ~ 740 nm. Excitations in the BChl c/d/e antenna are transferred to a lower- energy BChl a antenna absorbing at ~795 nm, prior to trapping at the reaction centers [2]. BChl c/d/e antennae in chlorosomes appear to be pigment oligomers whose structure is determined by pigment-pigment rather than pigment-protein interactions, because
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Chovet, Rogelio, Fethi Aloui, and Laurent Keirsbulck. "Wall Shear Stress Generated by Aqueous Flowing Foam." In ASME/JSME/KSME 2015 Joint Fluids Engineering Conference. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/ajkfluids2015-14039.

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Aqueous foam flow over horizontal channels present significant pressure losses originated by the wall shear stress. Understanding this phenomenon is of paramount importance for the oil, food and cosmetic industries. In this study, we validate the use of the innovative polarographic method, used to measure the wall shear stress. It measures an oxy-reduction reaction controlled by the convection and diffusion phenomenon. The most reliable way of obtaining the wall shear stress is through the pressure losses. They allow obtaining the pressure gradient along the length of the channel, which can be
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Bilan, Dmitri, Sergiu Cojocari, Vsevolod Pogrebnoi, Natalia Sucman, and Fliur Macaev. "The opening of dehydropregnenolone epoxide leading to the non-saturated skeletal rearrangement product." In Scientific seminar with international participation "New frontiers in natural product chemistry". Institute of Chemistry, Republic of Moldova, 2023. http://dx.doi.org/10.19261/nfnpc.2023.ab23.

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This report presents a compound that emerges as a product of the skeletal rearrangement following the opening of dehydropregnenolone epoxide (Figure 1). The opening of the epoxy cycle in dehydropregnenolone epoxide 1 in the presence of hydrochloric acid leads to the formation of two chromatographically inseparable diastereomers 2 and 3 (Figure 1).Figure 1. Scheme of the formation of diastereomers 2 and 3 In the literature, there is an example of the epoxide opening in absolute methanol. Thus, according to Girdhar et al [1], the reaction of compound 1 with dry HCl in dry MeOH at low temperature
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Eckhardt, Th, S. Haas, B. Lange, and H. Pfeiffer. "MEASUREMENT OF ELASTASE-INDUCED FIBRINOGEN-DERIVED PEPTIDES IN VITRO." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643165.

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Leukocyte elastase (EL) cleaves peptides from the N-terminal fibrinogen (fbg) Aα and B6 chains. The Aα peptide (Aα 1-21) and the as yet unidentified BIB peptide contain thrombin (TB)cleavage sites. As we were interested in fbg proteolysis in sepsis and leukemia, we have tried to measure these peptides (generated by incubating a crude granulocyte extract with fbg) using available fibrinopeptide A (FPA) - und Bß 15-42-antigen-RIA techniques. As the indirect measurement of Aα 1-21 in terms of FPA releasable by TB treatment in vitro (TB-inducible FPA, TIFPA) requires the use of a highly specific a
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Samarkin, Yevgeniy, Murtada Saleh Aljawad, Abduljamiu Olalekan Amao, et al. "Improving Long-Term Hydraulic Fracture Conductivity in Carbonate Formations by Substitution of Harder Minerals." In Abu Dhabi International Petroleum Exhibition & Conference. SPE, 2021. http://dx.doi.org/10.2118/208118-ms.

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Abstract Hydraulic fracturing is applied in tight formations to create conductive paths within the reservoir. However, the conductivity of the created fractures declines with time due to the closure stresses. The decline is sharp in soft formations because of proppant embedment and fracture surface asperities failure. The improvement in fracture surface hardness can mitigate the abovementioned challenges and sustain the fracture conductivity. This research targeted enhancing carbonate rock's hardness by forming minerals harder than calcite. Carbonate rocks, namely dolomite, limestone, and chal
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Reports on the topic "[4+21 Cycloaddition reaction"

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ธรรมรักษ์, เผด็จ. ผลของโรคเซอร์โคไวรัสในสุกรชนิดที่ 2 ต่อสมรรถภาพทางการสืบพันธุ์ในแม่สุกร : รายงานฉบับสมบูรณ์. คณะสัตวแพทยศาสตร์ จุฬาลงกรณ์มหาวิทยาลัย, 2014. https://doi.org/10.58837/chula.res.2014.72.

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เชื้อเซอร์โคไวรัสในสุกร (porcine circovirus, PCV) เป็นเชื้อไวรัสในสกุล Circoviridae ที่ถูกค้นพบครั้งแรกเมื่อ ปี ค.ศ. 1982 ในประเทศไทยมีรายงานการตรวจพบเชื้อ PCV ครั้งแรก ในสุกรอนุบาล ในปี ค.ศ. 1999 เชื้อ PCV โดยทั่วไปแบ่งเป็น 2 ชนิด ได้แก่ PCV type 1 (PCV1) และ PCV type 2 (PCV2) โดย PCV1 เป็นเชื้อที่ไม่ทำให้เกิดโรคในสุกร ในขณะที่ PCV2 ถูกค้นพบว่ามีความเกี่ยวข้องกับความผิดปกติหลายอย่างในสุกร เช่น ทำให้เกิดกลุ่มอาการ postweaning multisystemic wasting syndrome (PMWS) กลุ่มอาการ porcine dermatitis and nephropathy syndrome (PDNS) กลุ่มอาการความผิดปกติของระบบทางเดินหายใจ (porcine respiratory disease
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Volunteer Kinematics and Reaction in Lateral Emergency Maneuver Tests. SAE International, 2013. http://dx.doi.org/10.4271/2013-22-0013.

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It is important to understand human kinematics and muscle activation patterns in emergency maneuvers for the design of safety systems and for the further development of human models. The objective of this study was to quantify kinematic behavior and muscle activation in simulated steering tests in several realistic conditions. In total 108 tests were performed with 10 volunteers undergoing purely lateral maneuvers at 5 m/s2 deceleration or simulated lane change maneuvers at 5 m/s2 peak acceleration and peak yaw velocity of 25 °/s. Test subjects were seated on a rigid seat and restrained by a 4
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