scholarly journals A Simple Synthetic Method oftrans-5-Aryl and 5-Cyclopropyl Derivatives of 2-Isoxazolin-4-ol via Intramolecular Ring Opening of α,β-Epoxy Ketone Oximes

1990 ◽  
Vol 63 (9) ◽  
pp. 2739-2741 ◽  
Author(s):  
Shoei Ito ◽  
Masahiro Sato
Keyword(s):  
Ring Opening ◽  
Synthetic Method ◽  
Derivatives Of ◽  
Intramolecular Ring

scholarly journals Selective Synthesis of N-Acylnortropane Derivatives in Palladium-Catalysed Aminocarbonylation

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1813
Author(s):  
László Kollár ◽  
Ádám Erdélyi ◽  
Haroon Rasheed ◽  
Attila Takács
Keyword(s):  
Synthetic Method ◽  
Selective Synthesis ◽  
Varied Structure ◽  
Biological Importance ◽  
Aryl Iodides ◽  
Palladium Catalyzed ◽  
Derivatives Of

The aminocarbonylation of various alkenyl and (hetero)aryl iodides was carried out using tropane-based amines of biological importance, such as 8-azabicyclo[3.2.1]octan-3-one (nortropinone) and 3α-hydroxy-8-azabicyclo[3.2.1]octane (nortropine) as N-nucleophile. Using iodoalkenes, the two nucleophiles were selectively converted to the corresponding amide in the presence of Pd(OAc)2/2 PPh3 catalysts. In the presence of several iodo(hetero)arenes, the application of the bidentate Xantphos was necessary to produce the target compounds selectively. The new carboxamides of varied structure, formed in palladium-catalyzed aminocarbonylation reactions, were isolated and fully characterized. In this way, a novel synthetic method has been developed for the producing of N-acylnortropane derivatives of biological importance.

Derivatives of isatin in aqueous solution. I. Kinetics of ring opening of Isatin-5-sulfonate

1981 ◽  
Vol 34 (2) ◽  
pp. 365 ◽  
Author(s):  
H Stunzi
Keyword(s):  
Ring Opening ◽  
Rate Of Change ◽  
Spectroscopic Methods ◽  
Ph Values ◽  
Buffer Region ◽  
Pka Value ◽  
Back Titration ◽  
Kinetics Of ◽  
Derivatives Of ◽  
Sulfonate Anion

The reactions of isatin-5-sulfonate anion (si-) which cause a hysteresis in pH titrations were studied by pH-metric and n.m.r, spectroscopic methods. Rapid alkalimetric titrations [I 0.15 M (KNO3),37�] gave the pKa value corresponding to the addition of OH- to si- [pKa(ring) 9.55]. The slow ring opening to the sulfonatoisatate dianion (sia2-) led to a drift of the pH values towards an equilibrium buffer region. Its pKa, value [pKa(eq) 3.44] corresponds to the reaction si-+H2O ↔ sia 2-+H+ Rapid back-titration gave the pKa value of the ring-opened species Hsia- [pKa(open) c. 1.3]. The rate law for the ring opening d[sia]/dt=k2 [siOH](OH)+k1*[si] was obtained from the rate of change of pH. N-Methylisatin-5-sulfonate behaves analogously.

Intramolecular Ring-Opening Decomposition of Aryl Azetidines

2021 ◽  
Vol 12 (10) ◽  
pp. 1585-1588
Author(s):  
Guoyun Bai ◽  
Thomas N. O’Connell ◽  
Michael A. Brodney ◽  
Christopher R. Butler ◽  
Lara C. Czabaniuk ◽  
...  
Keyword(s):  
Ring Opening ◽  
Intramolecular Ring

scholarly journals Fates of imine intermediates in radical cyclizations of N-sulfonylindoles and ene-sulfonamides

2015 ◽  
Vol 11 ◽  
pp. 1649-1655 ◽  
Author(s):  
Hanmo Zhang ◽  
E Ben Hay ◽  
Stephen J Geib ◽  
Dennis P Curran
Keyword(s):  
Carbonyl Group ◽  
Ring Opening ◽  
Radical Cyclizations ◽  
Type Reaction ◽  
Primary Products ◽  
Lactam Carbonyl Group ◽  
Lactam Carbonyl ◽  
Imine Reduction ◽  
Derivatives Of

Two new fates of imine intermediates formed on radical cyclizations of ene-sulfonamides have been identified, reduction and hydration/fragmentation. Tin hydride-mediated cyclizations of 2-halo-N-(3-methyl-N-sulfonylindole)anilines provide spiro[indoline-3,3'-indolones] or spiro-3,3'-biindolines (derived from imine reduction), depending on the indole C2 substituent. Cyclizations of 2-haloanilide derivatives of 3-carboxy-N-sulfonyl-2,3-dihydropyrroles also presumably form spiro-imines as primary products. However, the lactam carbonyl group facilitates the ring-opening of these cyclic imines by a new pathway of hydration and retro-Claisen-type reaction, providing rearranged 2-(2'-formamidoethyl)oxindoles.

Phenolate-induced intramolecular ring-opening cyclization of N-tosylaziridines: access to functionalized benzoxacycles

2018 ◽  
Vol 16 (32) ◽  
pp. 5846-5858 ◽  
Author(s):  
Runjun Devi ◽  
Jonali Das ◽  
Bipul Sarma ◽  
Sajal Kumar Das
Keyword(s):  
Ring Opening ◽  
First Time ◽  
Intramolecular Ring

Phenolate-induced, diastereo- and regioselective intramolecular exo-tet ring-opening cyclization of N-tosylaziridines has been achieved for the first time.

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