scholarly journals A biomimetic approach to some specifically functionalized cyclic terpenoids.

2007 ◽  
Vol 54 (4) ◽  
pp. 679-693 ◽  
Author(s):  
Veaceslav Kulciţki
Keyword(s):  
Double Bond ◽  
Functional Groups ◽  
Ring Closure ◽  
Living Systems ◽  
Open Chain ◽  
Initial Substrate ◽  
Alpha Omega ◽  
Biomimetic Approach

The paper relates on the current advancements in the synthesis of complex cyclic terpenoids by superacidic induced cyclization of open chain precursors. It is shown that functional groups disposal in the initial substrate strongly influences the reaction outcome. Possible variations of the investigated compound structures include particularly alpha-functionalization and alpha,omega-bifunctionalization. This approach allowed a selective initiation of cyclization sequence from an internal double bond or suspending the ring closure cascade to partially cyclized compounds. The reported synthetic schemes are attempts to mimic the biogenetical processes postulated in the living systems.

Participation by some oxygen containing groups in hypobromous acid addition to double bond

1983 ◽  
Vol 48 (12) ◽  
pp. 3660-3673 ◽  
Author(s):  
Pavel Kočovský
Keyword(s):  
Double Bond ◽  
Functional Groups ◽  
Relative Reactivity ◽  
Product Analysis ◽  
Acid Addition ◽  
Hypobromous Acid ◽  
Electron Withdrawing Substituents

5(O)n and 6(O)π,n participations by some oxygen containing functional groups in the course of reaction with hypobromous acid have been studied on olefinic models of steroid type (I and II). The ability of these groups to participate has been compared on the basis of their relative reactivity with water (as externally attacking nucleophile) competing with participation. The results of the product analysis show that the ability to react with 5(O)n participation decreases in the order HO > CH3O ≃ CH3OCH2O > CH3CO2 > HCO2 > CH3SO3 ≥ (C2H5O)2PO2 > C6H5CO2 > O2NO ≫ CF3CO2, C2H5OCO2; in the last two functional groups is this ability completely suppressed. The 6(O)π,n participation comes in consideration only for compounds of the type II bearing the groups with the -X=O moiety which are ordered in the following sequence: C2H5OCO2 ≃ CH3CO2 ≥ (C2H5O)2PO2 > HCO2 > C6H5CO2. The remaining functional groups (CF3CO2, O2NO and CH3SO3do not undergo this process. Generally, it is valid that introduction of electron-withdrawing substituents into a participating group impedes or completely suppresses its ability to participate.

Double bond terminated Ln3+-doped LiYF4 nanocrystals with strong single band NIR emission: simple click chemistry route to make water dispersible nanocrystals with various functional groups

2016 ◽  
Vol 40 (4) ◽  
pp. 3080-3085 ◽  
Author(s):  
Brahmaiah Meesaragandla ◽  
Debashrita Sarkar ◽  
Venkata N. K. B. Adusumalli ◽  
Venkataramanan Mahalingam
Keyword(s):  
Double Bond ◽  
Click Chemistry ◽  
Functional Groups ◽  
Single Band ◽  
Water Dispersible ◽  
Nir Emission

A simple thiol–ene click chemistry strategy to develop upconverting nanocrystals with different functional groups.

Cu(II)-Catalyzed [3+2] Annulation of Thioamides with AIBN: Facile Access to Highly Functionalized Thiazolidine-4-ones

Synthesis ◽  
2021 ◽  
Author(s):  
Pragya Pali ◽  
Dhananjay Yadav ◽  
Gaurav Shukla ◽  
Maya Shankar Singh
Keyword(s):  
Double Bond ◽  
Functional Groups ◽  
Dual Role ◽  
Direct Access ◽  
One Pot ◽  
Simple Method ◽  
Two Component ◽  
Thiazolidine Ring ◽  
Coupling Partner

An efficient and versatile copper-catalyzed unprecedented intermolecular radical [3 + 2] annulation of thioamides with azobisisobutyronitrile (AIBN) is described. This two-component one-pot copper(II)-catalyzed transformation has been achieved via cascade formation of C-S/C−N bonds through the cyclization of in situ generated N,S-acetal intermediate from β-ketothioamide. This operationally simple method allows direct access to synthetically demanding thiazolidin-4-ones in good to excellent yields containing diverse functional groups of different electronic and steric nature. Remarkably, the readily available reaction partners, avoidance of expensive/toxic reagents and the gram scale synthesis are additional attributes to this strategy. AIBN here plays a dual role as radical initiator and unusual source of two carbon coupling partner. Notably, the products possess Z-stereochemistry with regard to the exocyclic C=C double bond at the 2-position of the thiazolidine ring.

Formation of glycosides by epoxidation-ring closure of open-chain hydroxyenol ethers obtained from sugars

1987 ◽  
pp. 1319 ◽  
Author(s):  
Francesco Nicotra ◽  
Luigi Panza ◽  
Fiamma Ronchetti ◽  
Giovanni Russo ◽  
Lucio Toma
Keyword(s):  
Ring Closure ◽  
Open Chain

Variability of Rhodium(III)-Catalyzed Reactions of Aromatic Oximes with Alkenes

Synlett ◽  
2020 ◽  
Vol 31 (11) ◽  
pp. 1117-1120 ◽  
Author(s):  
Dmitry S. Perekalin ◽  
Evgeniya A. Trifonova ◽  
Alina A. Komarova ◽  
Denis Chusov
Keyword(s):  
Double Bond ◽  
Functional Groups ◽  
Rhodium Catalyst ◽  
The Other ◽  
Chiral Catalyst ◽  
Enantiomeric Ratio ◽  
Other Hand ◽  
Terminal Alkenes ◽  
Catalyzed Reactions ◽  
Acetophenone Oxime

Acetophenone oxime reacts with various alkenes in the presence of the rhodium catalyst [Cp*RhCl2]2 (2.5 mol%; Cp* = pentamethylcyclopentadienyl) and 1,1,1,3,3,3-hexafluoropropan-2-ol as an important cosolvent. Styrene, aliphatic terminal alkenes, and strained cyclic alkenes gave the corresponding substituted dihydroisoquinolines in yields of 50–99%. On the other hand, alkenes containing functional groups close to the double bond gave a variety of different products. The reactions of acetophenone oxime with styrene or dec-1-ene in the presence of the chiral catalyst [(C5H2 t Bu2CH2 t Bu)RhI2]2 provided the corresponding dihydroisoquinolines with improved regioselectivity but a low enantiomeric ratio (61:39 in both cases).

Silver(I)-Catalyzed Deprenylation of Allylsulfonamide Derivatives

Synlett ◽  
2017 ◽  
Vol 28 (16) ◽  
pp. 2143-2146 ◽  
Author(s):  
Fuyuhiko Inagaki ◽  
Shisen Hira ◽  
Chisato Mukai
Keyword(s):  
Double Bond ◽  
Nitrogen Atom ◽  
Functional Groups ◽  
Silver Cation ◽  
Elimination Reaction

The silver(I)-catalyzed deprenylation of sulfonamide bearing prenyl functional groups on the nitrogen atom has been developed. In this reaction, the prenyl moiety was selectively eliminated without allyl or benzyl cleavage on the nitrogen atom. In addition, geranyl was also applicable for this elimination reaction. Furthermore, sulfonamide possessing two prenyl groups underwent a double deprenylation to form the corresponding deprenylated sulfonamide. Thus, a novel reactivity between the silver cation and double bond was observed.

Mapping the Distribution of Double Bond Location Isomers in Lipids across Mouse Tissues

The Analyst ◽  
2021 ◽  
Author(s):  
Hanlin Ren ◽  
Alexander Triebl ◽  
Markus Wenk ◽  
Yu Xia ◽  
Federico Torta
Keyword(s):  
Double Bond ◽  
Drug Targets ◽  
Metabolic Diseases ◽  
Living Systems ◽  
Lipid Homeostasis ◽  
Mouse Tissues

Lipids are highly diverse and essential biomolecules in all living systems. As lipid homeostasis is often perturbed in metabolic diseases, these molecules can serve as both biomarkers and drug targets....

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