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21 pages, 2917 KB

Open AccessArticle

Synthesis and Thiol-Ene Photopolymerization of Bio-Based Hybrid Aromatic–Aliphatic Monomers Derived from Limonene, Cysteamine and Hydroxycinnamic Acid Derivatives

by Ricardo Acosta Ortiz, Jorge Luis Robles Olivares and Roberto Yañez Macias

Polymers 2024, 16(23), 3295; https://doi.org/10.3390/polym16233295 - 26 Nov 2024

Cited by 3 | Viewed by 3063

Abstract

Three novel bio-based monomers were synthesized through an amidation reaction involving allylated derivatives of coumaric, ferulic and phloretic acid and a diamine obtained from a thiol-ene coupling reaction between limonene and cysteamine. The monomers containing the enone bond of the cinnamic moiety underwent photoisomerization and photocycloaddition reactions upon UV light irradiation. All three monomers were photocured via thiol-ene photopolymerization using a glycerol-derived trifunctional thiol, resulting in fully bio-based poly(amide–thioether)s. The polymers derived from monomers that contain the enone bond exhibited glass transition (T_g) temperatures of 85 °C when a stoichiometric ratio of the thiol was used, whereas polymers in which an excess of thiol was used exhibited T_g temperatures of 61 and 74 °C. The higher T_g of the synthesized polymers, compared with other reported polymers produced from thiol-ene photopolymerizations, was attributed to the combination of the aromatic rings of the cinnamic moiety and the cycloaliphatic ring of limonene, as well as the presence of the amide groups in the polymer, which can induce hydrogen bonding. The development of high T_g polymers from bio-based monomers through thiol-ene photopolymerization represents a significant advancement in the polymer synthesis sector, offering an improved performance and sustainability. Full article

(This article belongs to the Special Issue Photopolymerization: Materials, Applications and Challenges)

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12 pages, 2430 KB

Open AccessArticle

Natural Thiols, but Not Thioethers, Attenuate Patulin-Induced Endoplasmic Reticulum Stress in HepG2 Cells

by Hye Mi Kim, Hwa Young Choi, Gun Hee Cho, Ju Hee Im, Eun Young Hong and Hyang Sook Chun

Toxins 2021, 13(10), 727; https://doi.org/10.3390/toxins13100727 - 14 Oct 2021

Cited by 6 | Viewed by 3518

Abstract

Patulin, a mycotoxin, is known to have cytotoxic effects, but few studies have focused on the involvement of the endoplasmic reticulum (ER) stress response in patulin toxicity and the natural compounds that attenuate it in HepG2 cells. This study tested the ability of patulin to induce ER stress, and that of four thiols and three thioethers to attenuate patulin-induced ER stress in HepG2 cells. Patulin dose-dependently inhibited cell proliferation (IC₅₀, 8.43 μM). Additionally, patulin was found to increase the expression levels of ER stress-related genes and/or protein markers, including BiP, CHOP, and spliced XBP1, in HepG2 cells compared to the vehicle control, indicating its potential in ER stress induction. Patulin-induced cytotoxicity in HepG2 cells was reduced by naturally occurring thiol compounds (glutathione, L-acetyl-L-cysteine, cysteine, and captopril), but not by thioether compounds (sulforaphane, sulforaphene, and S-allyl-L-cysteine). Patulin-thiol co-treatment decreased CHOP expression and BiP and CHOP levels in HepG2 cells but did not alter BiP expression. Spliced XBP1 expression was decreased by patulin-thiol co-treatment. Thus, patulin induced ER stress in HepG2 cells and thiols, but not in thioethers, attenuated patulin-induced ER stress. Full article

(This article belongs to the Section Mycotoxins)

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11 pages, 2927 KB

Open AccessArticle

New Nitrogen, Sulfur-, and Selenium-Donating Ligands Derived from Chiral Pyridine Amino Alcohols. Synthesis and Catalytic Activity in Asymmetric Allylic Alkylation

by Marzena Wosińska-Hrydczuk and Jacek Skarżewski

Molecules 2021, 26(12), 3493; https://doi.org/10.3390/molecules26123493 - 8 Jun 2021

Cited by 11 | Viewed by 3756

Abstract

Although many chiral ligands for asymmetric catalysis have been developed, there is still a need for new structures allowing the modular approach. Recently, easy synthesis of chiral pyridine-containing β-amino alcohols has been elaborated by opening respective epoxides with enantiomeric 1-phenylethylamine. This paper reports the synthetic transformation of β-amino alcohols into the new complexing pyridine-containing seleno- and thioethers. The amino alcohols were effectively converted to cyclic sulfonamidates, which were reacted with thiolates or phenyl selenide nucleophile. The reaction was diastereoselective, and its outcome depended on the configuration at the substitution center. The problem was discussed considering DFT optimized structures of both diastereomeric sulfonamidates. New amino-aldimine ligands were also synthesized from chiral pyridine-containing diamines. Nine new chiral ligands were tested in the Tsuji-Trost allylic alkylation resulting in the enantiomerically enriched product in up to 75% ee. The observed stereochemical induction agrees with the prevailing nucleophilic attack at the allylic carbon laying opposite to the complexing nitrogen of pyridine in η³-allylic intermediate complexes. Full article

(This article belongs to the Special Issue In Honor of the 80th Birthday of Professor Janusz Jurczak)

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26 pages, 5422 KB

Open AccessArticle

Structural Analysis of Oxidized Cerebrosides from the Extract of Deep-Sea Sponge Aulosaccus sp.: Occurrence of Amide-Linked Allylically Oxygenated Fatty Acids

by Elena A. Santalova, Vladimir A. Denisenko and Pavel S. Dmitrenok

Molecules 2020, 25(24), 6047; https://doi.org/10.3390/molecules25246047 - 21 Dec 2020

Cited by 7 | Viewed by 3591

Abstract

The structural elucidation of primary and secondary peroxidation products, formed from complex lipids, is a challenge in lipid analysis. In the present study, rare minor oxidized cerebrosides, isolated from the extract of a far eastern deep-sea glass sponge, Aulosaccus sp., were analyzed as constituents of a multi-component RP-HPLC (high-performance liquid chromatography on reversed-phase column) fraction using NMR (nuclear magnetic resonance) spectroscopy, mass spectrometry, GC (gas chromatography), and chemical transformations (including hydrogenation or derivatization with dimethyl disulfide before hydrolysis). Eighteen previously unknown β-D-glucopyranosyl-(1→1)-ceramides (1a–a^//, 1b–b^//, 2a–a^//, 2b–b^//, 3c–c^//, 3d–d^//) were shown to contain phytosphingosine-type backbones (2S,3S,4R,11Z)-2-aminoeicos-11-ene-1,3,4-triol (in 1), (2S,3S,4R,13Z)-2-aminoeicos-13-ene-1,3,4-triol (in 2), and (13S*,14R*)-2-amino-13,14-methylene-eicosane-1,3,4-triol (in 3). These backbones were N-acylated with straight-chain monoenoic (2R)-2-hydroxy acids that had allylic hydroperoxy/hydroxy/keto groups on C-17^/ in the 15^/E-23:1 chain (a–a^//), C-16^/ in the 17^/E-23:1 (b–b^//) and 14^/E-22:1 (c–c^//) chains, and C-15^/ in the 16^/E-22:1 chain (d–d^//). Utilizing complementary instrumental and chemical methods allowed for the first detailed structural analysis of a complex mixture of glycosphingolipids, containing allylically oxygenated monoenoic acyl chains. Full article

(This article belongs to the Special Issue Dedicated to the 55th Anniversary of G.B. Elyakov Pacific Institute of Bioorganic Chemistry of the Far Eastern Branch of the Russian Academy of Sciences)

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8 pages, 1393 KB

Open AccessArticle

A Stable Coordination Polymer Based on Rod-Like Silver(I) Nodes with Contiguous Ag-S Bonding

by Harley D. Betts, Oliver M. Linder-Patton and Christopher J. Sumby

Molecules 2020, 25(19), 4548; https://doi.org/10.3390/molecules25194548 - 4 Oct 2020

Cited by 7 | Viewed by 4180

Abstract

Silver(I)-based coordination polymers or metal-organic frameworks (MOFs) display useful antibacterial properties, whereby distinct materials with different bonding can afford control over the release of silver(I) ions. Such silver(I) materials are comprised of discrete secondary building units (SBUs), and typically formed with ligands possessing only soft or borderline donors. We postulated that a linker with four potential donor groups, comprising carboxylate and soft thioether donors, 2,5-bis (allylsulfanyl) benzene dicarboxylic acid (ASBDC), could be used to form stable, highly connected coordination polymers with silver(I). Here, we describe the synthesis of a new material, (Ag₂(ASBDC)), which possesses a rod-like metal node-based 3D honeycomb structure, strongly π-stacked linkers, and steric bulk to protect the node. Due to the rod-like metal node and the blocking afforded by the ordered allyl groups, the material displays notable thermal and moisture stability. An interesting structural feature of (Ag₂(ASBDC)) is contiguous Ag–S bonding, essentially a helical silver chalcogenide wire, which extends through the structure. These interesting structural features, coupled with the relative ease by which MOFs made with linear dicarboxylate linkers can be reticulated, suggests this may be a structure type worthy of further investigation. Full article

(This article belongs to the Special Issue Functional Metal-Organic Framework Based Materials)

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7 pages, 3761 KB

Open AccessCommunication

Synthesis of Thioethers by InI₃-Catalyzed Substitution of Siloxy Group Using Thiosilanes

by Yoshihiro Nishimoto, Aya Okita, Akio Baba and Makoto Yasuda

Molecules 2016, 21(10), 1330; https://doi.org/10.3390/molecules21101330 - 6 Oct 2016

Cited by 5 | Viewed by 7356

Abstract

The substitution of a siloxy group using thiosilanes smoothly occurred in the presence of InI₃ catalyst to yield the corresponding thioethers. InI₃ was a specifically effective catalyst in this reaction system, while other typical Lewis acids such as BF₃⋅OEt₂, AlCl₃, and TiCl₄were ineffective. Various silyl ethers such as primary alkyl, secondary alkyl, tertiary alkyl, allylic, benzylic, and propargylic types were applicable. In addition, bulky OSitBuMe₂ and OSiiPr₃ groups, other than the OSiMe₃ group, were successfully substituted. The substitution reaction of enantiopure secondary benzylic silyl ether yielded the corresponding racemic thioether product, which suggested that the reaction of tertiary alkyl, secondary alkyl, benzylic, and propargylic silyl ethers would proceed via a S_N1 mechanism. Full article

(This article belongs to the Special Issue Advances in Silicon Chemistry)

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