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Organic & Biomolecular Chemistry Apr 2021This review details the isolation, biosynthesis, biological activity and synthesis of spiroacetals from the myxobacterium Sorangium cellulosum. The strategies utilised... (Review)
Review
This review details the isolation, biosynthesis, biological activity and synthesis of spiroacetals from the myxobacterium Sorangium cellulosum. The strategies utilised to access the challenging structures and stereochemistry of these natural products are highlighted.
Topics: Acetals; Biological Products; Molecular Conformation; Sorangium; Spiro Compounds; Stereoisomerism
PubMed: 33683270
DOI: 10.1039/d1ob00026h -
Organic & Biomolecular Chemistry Aug 2022In this report, we demonstrate that visible light photoactivation of 6-bromo-2-naphthol facilitates the photoacid-catalyzed acetalization of carbonyls with alcohols. We...
In this report, we demonstrate that visible light photoactivation of 6-bromo-2-naphthol facilitates the photoacid-catalyzed acetalization of carbonyls with alcohols. We also demonstrate that 2-naphthol when coupled to a photosensitizer provides acetals from electron-deficient aldehydes. In addition, the S excited state p for 6-bromo-2-naphthol in water was determined and shown to have increased excited-state acidity relative to 2-naphthol.
Topics: Acetals; Alcohols; Aldehydes; Catalysis; Molecular Structure
PubMed: 35876112
DOI: 10.1039/d2ob00435f -
Organic Letters Jul 2023After a recent total synthesis had resolved all issues surrounding the constitution and stereostructure of prorocentin, it was possible to devise a new approach aiming...
After a recent total synthesis had resolved all issues surrounding the constitution and stereostructure of prorocentin, it was possible to devise a new approach aiming at an improved supply of this scarce marine natural product; this compound is a cometabolite of the prototypical phosphatase inhibitor okadaic acid but still awaits detailed biological profiling. The revised entry starts from 2-deoxy-d-glucose; keys to success were a telescoped hemiacetal reduction/acetal cleavage and an exquisitely selective gold/Brønsted acid-cocatalyzed spiroacetalization.
Topics: Okadaic Acid; Enzyme Inhibitors; Furans; Acetals
PubMed: 37358405
DOI: 10.1021/acs.orglett.3c01720 -
Journal of the American Chemical Society Jun 2010A catalytic enantioselective transacetalization has been developed. The chiral phosphoric acid TRIP was demonstrated to be an efficient and highly enantioselective...
A catalytic enantioselective transacetalization has been developed. The chiral phosphoric acid TRIP was demonstrated to be an efficient and highly enantioselective catalyst for the activation of O,O-acetals. The reaction enables the asymmetric synthesis of acetals with the acetal carbon as the only stereogenic center.
Topics: Acetals; Catalysis; Models, Molecular; Molecular Conformation; Stereoisomerism; Substrate Specificity
PubMed: 20527773
DOI: 10.1021/ja102753d -
Journal of Controlled Release :... Dec 2020Utilization of unique acidic environment in various disease sites has been quite advantageous in targeted drug delivery. Among the widely explored pH-sensitive moieties... (Review)
Review
Utilization of unique acidic environment in various disease sites has been quite advantageous in targeted drug delivery. Among the widely explored pH-sensitive moieties such as hydrazone, orthoester, imine, vinylether, etc., the acetal bearing compounds are one of the most explored entities in targeted and improved drug delivery to treat disease conditions at the preclinical stage. This review addresses the design and synthesis of various acetal-based polymers as pH-responsive nano-drug delivery systems in the form of micelles, polymersomes, nanoplexes and polymeric and solid lipid nanoparticles for biomedical applications. The review will identify potential advantages, key challenges and future prospects of acetal-based pH-responsive drug delivery systems. The novel developments, strategies and suggestions described may guide the formulation scientists to optimize acetal-based pH-responsive drug delivery systems as an approach to treat various diseases.
Topics: Acetals; Drug Carriers; Drug Delivery Systems; Hydrogen-Ion Concentration; Micelles; Nanoparticles; Polymers
PubMed: 32980419
DOI: 10.1016/j.jconrel.2020.09.044 -
Macromolecular Bioscience Nov 2021Protecting group chemistry is essential for various organic transformation and polymerization processes. In particular, conventional anionic ring-opening polymerization... (Review)
Review
Protecting group chemistry is essential for various organic transformation and polymerization processes. In particular, conventional anionic ring-opening polymerization (AROP) often requires proper protecting group chemistry because it is typically incompatible with most functional groups due to the highly basic and nucleophilic conditions. In this context, many functional epoxide monomers with proper protecting groups are developed, including the acetal group as a representative example. Since the early introduction of ethoxyethyl glycidyl ether, there is significant development of acetal-based monomers in the polyethers. These monomers are now utilized not only as protecting groups for hydroxyl groups under AROP conditions but also as pH-responsive moieties for biomedical applications, further expanding their utility in the use of functionalized polyethers. Recent progress in this field is outlined from their synthesis, polymerization, and biomedical applications.
Topics: Acetals; Epoxy Compounds; Hydrogen-Ion Concentration; Polymerization; Polymers
PubMed: 34369084
DOI: 10.1002/mabi.202100251 -
Biomacromolecules Sep 2022A small library of degradable polyester-like glycopolymers was successfully prepared by the combination of radical ring-opening copolymerization of...
A small library of degradable polyester-like glycopolymers was successfully prepared by the combination of radical ring-opening copolymerization of 2-methylene-1,3-dioxepane as a cyclic ketene acetal (CKA) with vinyl ether (VE) derivatives and a Pd-catalyzed thioglycoconjugation. The resulting thioglycopolymers were formulated into self-stabilized thioglyconanoparticles, which were stable up to 4 months and were enzymatically degraded. Nanoparticles and their degradation products exhibited a good cytocompatibility on two healthy cell lines. Interactions between thioglyconanoparticles and lectins were investigated and highlighted the presence of both specific carbohydrate/lectin interactions and nonspecific hydrophobic interactions. Fluorescent thioglyconanoparticles were also prepared either by encapsulation of Nile red or by the functionalization of the polymer backbone with rhodamine B. Such nanoparticles were used to prove the cell internalization of the thioglyconanoparticles by lung adenocarcinoma (A549) cells, which underlined the great potential of P(CKA--VE) copolymers for biomedical applications.
Topics: Acetals; Ethers, Cyclic; Nanoparticles; Polymerization; Polymers
PubMed: 35971824
DOI: 10.1021/acs.biomac.2c00851 -
Fitoterapia Jun 2020Four undescribed oxylipin vanillyl acetals with four stereogenic carbons were isolated from the herbs of Solanum lyratum. A comprehensive set of spectroscopic methods...
Four undescribed oxylipin vanillyl acetals with four stereogenic carbons were isolated from the herbs of Solanum lyratum. A comprehensive set of spectroscopic methods were used to elucidate the structures and relative configurations of 1-4. The absolute configurations of the naturally occurring compounds are assigned as 7S, 9'S, 10'S, 11'R at the site of six-membered cyclic acetal attachment by electronic circular dichroism (ECD) calculations and the modified Mosher's method. Compounds 1 and 3 displayed moderate selective inhibition against Hep3B and HepG2 cells, respectively. Further Annexin V-FITC/PI staining assay revealed that 1 and 3 might have inhibitory effects on hepatoma cells through induction of apoptosis.
Topics: Acetals; Antineoplastic Agents, Phytogenic; Apoptosis; China; Hep G2 Cells; Humans; Molecular Structure; Oxylipins; Phytochemicals; Solanum
PubMed: 32199958
DOI: 10.1016/j.fitote.2020.104559 -
CRC Critical Reviews in Food Science... Nov 1979The formation of flavor in fermented beverages is due to various biosynthetic mechanisms. In wine, flavors arise as the result of compounds: 1. Originating from the... (Review)
Review
The formation of flavor in fermented beverages is due to various biosynthetic mechanisms. In wine, flavors arise as the result of compounds: 1. Originating from the native fruit (grap) 2. Which are formed or altered during the various processes employed in production 3. Which are developed or transformed by yeast during fermentation 4. Arise during the aging process In this review the results of investigations on the development of flavors in grape and wine will be discussed. Special attention will be devoted to the effects of specific processes in winemaking on the development of flavor.
Topics: Acetals; Acetamides; Alcohols; Aldehydes; Carboxylic Acids; Esters; Fatty Acids, Volatile; Fermentation; Fruit; Hydrocarbons; Ketones; Lactones; Odorants; Phenols; Saccharomyces cerevisiae; Taste; Wine
PubMed: 389563
DOI: 10.1080/10408397909527273 -
Angewandte Chemie (International Ed. in... Jan 2014Pectenotoxin-2 (PTX2) is a shellfish toxin and has a non-anomeric spiroacetal, which is not stabilized by an anomeric effect. The selective construction of the...
Pectenotoxin-2 (PTX2) is a shellfish toxin and has a non-anomeric spiroacetal, which is not stabilized by an anomeric effect. The selective construction of the non-anomeric spiroacetal has been a major problem in the synthesis of PTX2. Described herein is the stereoselective total synthesis of PTX2 via the isomerization of anomeric spiroacetal pectenotoxin-2b (PTX2b). The synthesis of PTX2b was achieved by a simple process including sulfone-mediated assembly of spirocyclic and bicyclic acetals and subsequent macrocyclization by ring-closing olefin metathesis. Finally, the selective construction of PTX2 was accomplished by the early termination of a dynamic transition process to equilibrium in the acid-catalyzed isomerization of anomeric PTX2b. [6,6]-Spiroacetal pectenotoxin-2c (PTX2c) was also synthesized from PTX2b. The cytotoxicity assay of the synthetic compounds against HepG2 and Caco2 cancer cells showed a potency of the order: PTX2≫PTX2b>PTX2c.
Topics: Acetals; Caco-2 Cells; Cell Survival; Cyclization; Furans; Hep G2 Cells; Humans; Isomerism; Macrolides; Pyrans; Spiro Compounds
PubMed: 24288200
DOI: 10.1002/anie.201308502