- O-to-S Substitution Enables Dovetailing Conflicting Cyclizability, Polymerizability, and Recyclability: Dithiolactone vs. Dilactone
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Developing chemically recyclable polymers represents a greener alternative to landfill and incineration and offers a closed-loop strategy toward a circular materials economy. However, the synthesis of chemically recyclable polymers is still plagued with certain fundamental limitations, including trade-offs between the monomer's cyclizability and polymerizability, as well as between polymer's depolymerizability and properties. Here we describe the subtle O-to-S substitution, dithiolactone monomers derived from abundant feedstock α-amino acids can demonstrate appealing chemical properties different from those of dilactone, including accelerated ring closure, augmented kinetics polymerizability, high depolymerizability and selectivity, and thus constitute a unique class of polythioester materials exhibiting controlled molecular weight (up to 100.5 kDa), atactic yet high crystallinity, structurally diversity, and chemical recyclability. These polythioesters well addresses the formidable challenges of developing chemically recyclable polymers by having an unusual set of desired properties, including easy-to-make monomer from ubiquitous feedstock, and high polymerizability, crystallinity and precise tunability of physicochemical performance, as well as high depolymerizability and selectivity. Computational studies explain why O-to-S modification of polymer backbone enables dovetailing desirable, but conflicting, performance into one polymer structure.
- Wang, Yanchao,Li, Maosheng,Chen, Jinlong,Tao, Youhua,Wang, Xianhong
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supporting information
p. 22547 - 22553
(2021/09/09)
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- Catalytic enantioselective synthesis of tertiary thiols from 5h-thiazol-4-ones and nitroolefins: Bifunctional ureidopeptide-based bronsted base catalysis
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Fully loaded: The ureidopeptide-based bifunctional Bronsted base 1 efficiently promotes the first direct catalytic Michael reaction of α-mercapto carboxylate surrogates with nitroolefins involving a fully substituted α-carbon atom construction. Copyright
- Diosdado, Saioa,Etxabe, Julen,Izquierdo, Joseba,Landa, Aitor,Mielgo, Antonia,Olaizola, Iurre,Lopez, Rosa,Palomo, Claudio
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supporting information
p. 11846 - 11851
(2013/11/19)
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- Asymmetric synthesis of the four diastereoisomers of a novel non-steroidal farnesoid X receptor (FXR) agonist: Role of the chirality on the biological activity
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An asymmetric synthetic strategy was designed for the preparation of the four possible diastereoisomers of 3,6-dimethyl-1-(2-methylphenyl)-4-(4- phenoxyphenyl)-4,8-dihydro-1H-pyrazolo[3,4-e][1,4]thiazepin-7-one, a non-steroidal FXR agonist, we recently discovered following a virtual screening approach. The results obtained from an AlphaScreen assay clearly demonstrated that only the isomer endowed with 4R,6S absolute configuration is responsible for the biological activity. A deep investigation of the different putative binding modes adopted by these enantiomerically pure ligands using computational modeling studies confirmed the enantioselectivity of FXR towards this class of molecules.
- Marinozzi, Maura,Carotti, Andrea,Sardella, Roccaldo,Buonerba, Federica,Ianni, Federica,Natalini, Benedetto,Passeri, Daniela,Rizzo, Giovanni,Pellicciari, Roberto
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supporting information
p. 3780 - 3789
(2013/07/19)
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- Asymmetric michael addition of substituted rhodanines to α,β-unsaturated ketones catalyzed by bulky primary amines
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A bulky group was introduced by design into a diamine catalyst, and a series of robust and tunable bulky chiral primary amine catalysts were developed and successfully applied in the direct conjugate addition of substituted rhodanines to α,β-unsaturated ketones. High yields (up to 99%) and excellent diastereoselectivities (up to 99:1 dr) and enantioselectivities (up to 98% ee) were observed.
- Yu, Feng,Hu, Haoxiang,Gu, Xiaodong,Ye, Jinxing
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supporting information; scheme or table
p. 2038 - 2041
(2012/07/28)
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- 2-Mercaptoaldehyde dimers and 2,5-dihydrothiophenes from 1,3-oxathiolan-5-ones
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Representative 1,3-oxathiolan-5-ones (6), prepared from 2-mercaptoacids, have been reduced to 2-mercaptoaldehydes 1 with diisobutylaluminum hydride.The aldehydes 1, which appear to exist in several dimeric forms, react with vinyltriphenylphosphonium bromide to give 2,5-dihydrothiophenes.
- McIntosh, John M.,Siddiqui, Maqbool A.
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p. 1872 - 1875
(2007/10/02)
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- Azole derivatives
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Azole derivatives of the formula SPC1 Wherein R1 is free or esterified carboxyl or other functionally modified carboxyl group, R2 and R3 each are aryl; A is Cn H2n in which n is an integer from 1 to 10, inclusive; and Z is O or S; and the physiologically acceptable salts thereof, possess, with good compatibility, excellent antiphlogistic activity and, in particular, influence favorably the chronic progressive diseases of the joints, e.g., arthritis. They can be prepared from compounds of the formula SPC2 Wherein X1 is a group convertible into the group --S--A--R1, and R2 and R3 have the values given above.
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