The saddle point of the nucleophilic substitution reaction Cl

1998 ◽  
Vol 99 (6) ◽  
pp. 426 ◽  
Author(s):  
Peter Botschwina
Keyword(s):  
Saddle Point ◽  
Nucleophilic Substitution ◽  
Substitution Reaction ◽  
Nucleophilic Substitution Reaction

scholarly journals Synthesis of Carbohydrate Based Macrolactones and Their Applications as Receptors for Ion Recognition and Catalysis

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3394
Author(s):  
Surya B. Adhikari ◽  
Anji Chen ◽  
Guijun Wang
Keyword(s):  
Nucleophilic Substitution ◽  
Supramolecular Chemistry ◽  
Copper Sulfate ◽  
Substitution Reaction ◽  
Biological Properties ◽  
Anion Binding ◽  
Nucleophilic Substitution Reaction ◽  
Binding Properties ◽  
Intramolecular Nucleophilic Substitution ◽  
Leaving Groups

Glycomacrolactones exhibit many interesting biological properties, and they are also important in molecular recognitions and for supramolecular chemistry. Therefore, it is important to be able to access glycomacrocycles with different sizes and functionality. A new series of carbohydrate-based macrocycles containing triazole and lactone moieties have been designed and synthesized. The synthesis features an intramolecular nucleophilic substitution reaction for the macrocyclization step. In this article, the effect of some common sulfonate leaving groups is evaluated for macrolactonization. Using tosylate gave good selectivity for monolactonization products with good yields. Fourteen different macrocycles have been synthesized and characterized, of which eleven macrocycles are from cyclization of the C1 to C6 positions of N-acetyl D-glucosamine derivatives and three others from C2 to C6 cyclization of functionalized D-glucosamine derivatives. These novel macrolactones have unique structures and demonstrate interesting anion binding properties, especially for chloride. The macrocycles containing two triazoles form complexes with copper sulfate, and they are effective ligands for copper sulfate mediated azide-alkyne cycloaddition reactions (CuAAC). In addition, several macrocycles show some selectivity for different alkynes.

Lewis-Acid-Catalyzed Direct Nucleophilic Substitution Reaction of Alcohols for the Functionalization of Aromatic Amines

2019 ◽  
Vol 4 (4) ◽  
pp. 1371-1374 ◽  
Author(s):  
Onkar S. Nayal ◽  
Maheshwar S. Thakur ◽  
Rohit Rana ◽  
Rahul Upadhyay ◽  
Sushil K. Maurya
Keyword(s):  
Nucleophilic Substitution ◽  
Lewis Acid ◽  
Aromatic Amines ◽  
Substitution Reaction ◽  
Nucleophilic Substitution Reaction ◽  
Acid Catalyzed

Synthesis of Steroid–Porphyrin Conjugates from Oestradiol, Oestrone, and Lithocholic Acid

2014 ◽  
Vol 67 (11) ◽  
pp. 1632 ◽  
Author(s):  
Fargol Taba ◽  
Tze Han Sum ◽  
Paul J. Sintic ◽  
Ann H. Lundmark ◽  
Maxwell J. Crossley
Keyword(s):  
Nucleophilic Substitution ◽  
Substitution Reaction ◽  
Lithocholic Acid ◽  
The Other ◽  
Nucleophilic Substitution Reaction ◽  
Porphyrin Synthesis ◽  
Synthesis Reactions ◽  
Steroid Conjugates ◽  
The Way

The synthesis of porphyrin–steroid conjugates is examined using the natural steroids oestradiol, oestrone, and lithocholic acid as precursors. Two strategies differing in the timing of formation of the steroid–porphyrin linkage leading to four different construction motifs are explored. Two approaches are based on a strategy of introduction of steroidal components in the porphyrin-forming reaction involving condensation of steroidal-alkylaldehydes and pyrrole to give 5,10,15,20-tetrakis(steroidal-alkyl)porphyrins and differ in the way in which the required aldehyde is introduced to the steroidal component. In the other strategy, a steroidal component is introduced by post-porphyrin synthesis reactions and here also two approaches were explored, one involving nucleophilic substitution and the other esterification. Of the four approaches investigated, the most efficient and most versatile one attaches the steroidal components late in the sequence to a 5,10,15,20-tetra(ω-haloalkyl)porphyrin by a nucleophilic substitution reaction. In this way, a 5,10,15,20-tetrakis[oestrone-linked-heptyl)porphyrin was obtained in 47 % yield.

BF3·Et2O- or DMAP-Catalyzed Double Nucleophilic Substitution Reaction of Aziridinofullerenes with Sulfamides or Amidines

2014 ◽  
Vol 79 (23) ◽  
pp. 11744-11749 ◽  
Author(s):  
Hai-Tao Yang ◽  
Meng-Lei Xing ◽  
Xin-Wei Lu ◽  
Jia-Xing Li ◽  
Jiang Cheng ◽  
...  
Keyword(s):  
Nucleophilic Substitution ◽  
Substitution Reaction ◽  
Nucleophilic Substitution Reaction
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