Some Thiazolylthio Hydroquinones

Newby, Thomas H.; Howlett, Elizabeth C.

doi:10.1021/ja01154a070

Cited by 5 publications

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“…As an alternative to the S N Ar approach, we envisioned the conjugate addition of a dithiol and a bis-benzoquinone as a synthetic strategy for constructing the requisite arylthio-hydroquinone linkages in PPHS (Scheme c). Thiol addition to α,β-unsaturated carbonyl systems (otherwise referred to as thiol-Michael or thiol-click reactions) is an indispensable approach in polymer synthesis and functionalization; , however, thiol-benzoquinone conjugate addition chemistry has rarely been applied in the synthesis of polymers. ,, Despite the apparent efficacy of this reaction in simple small-molecule systems, − closer examination reveals that reactions performed at stoichiometric equivalence generate mixtures of uncoupled hydroquinones ( R-HQ ) and overoxidized and secondary-addition products as the result of rapid benzoquinone-hydroquinone redox isomerization (Scheme a, pathway I). − This level of infidelity is deleterious for a step-growth polymerization (e.g., between a dithiol and bis-benzoquinone as shown in Scheme c), which mandates strict stoichiometric parity to proceed to a high-molecular-weight polymer.…”

Section: Introductionmentioning

confidence: 99%

Functional, Redox-Responsive Poly(phenylene sulfide)-Based Gels

2019

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Poly(p-phenylene sulfide) (PPS) is a highly robust thermoplastic with outstanding thermal and chemical stability. However, development of functional PPS-based materials is hampered by harsh synthetic conditions and poor solubility. As an alternative to nucleophilic aromatic substitution (SNAr), we report herein on the use of benzoquinone conjugate addition chemistry to prepare PPS-derivatives bearing redoxactive hydroquinones in the polymer backbone. Specifically, we utilize thiosilanes as thiol surrogates in order to attenuate unproductive redox-isomerization reactions and to provide a thermodynamic driving force for polymerization. The silyl transfer conjugate addition process results in a poly(phenylene silylhydroquinone sulfide) (PPSHS) amenable to several divergent modes of functionalization. Notably, the so-formed PPSHS exist as gels which swell organic solvents and exhibit distinct changes in color and swelling upon redox changes. By repeated cycling of oxidation and thiol conjugate addition, the crosslinked networks can be depolymerized under ambient conditions. Finally, we prepared an interpenetrating polymer network (IPN) comprised of PPSHS and cross-linked poly(n-butyl acrylate) which exhibits a significant enhancement in thermomechanical properties over the base materials.

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Section: Introductionmentioning

confidence: 99%

Functional, Redox-Responsive Poly(phenylene sulfide)-Based Gels

2019

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“…On the other hand, it is well known that N-unsubstituted thioamides undergo Michael additions with a,b-unsaturated carbonyl compounds. [6] Michael additions of N-substituted thiocarbamates, however, are scarcely known, though Palomo and co-workers reported the sulfur-transfer reaction of N-enoyl thiocarbamates with a Lewis acid followed by hydrolysis of the products. [7] Results and Discussion…”

Section: Introductionmentioning

confidence: 99%

Asymmetric Tandem Michael‐Aldol Reactions between 3‐Cinnamoyloxazolidine‐2‐thiones and Aldehydes

Kinoshita

Osamura

Mizuno

et al. 2006

Chemistry A European J

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Reactions between chiral 3-cinnamoyl-4-methyl-5-phenyl-1,3-oxazolidine-2-thiones and aromatic aldehydes in the presence of BF3Et2O diastereoselectively produced tricyclic compounds incorporating a bridgehead carbon bound to four heteroatoms in high yields. Four stereocenters were induced during the reaction. The tricyclic products were transformed into propane-1,3-diols bearing three consecutive stereocenters by acid hydrolysis, S-methylation, and reductive removal of the chiral auxiliary.

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Intra- and Intermolecular C−S Bond Formation Using a Single Catalytic System: First Direct Access to Arylthiobenzothiazoles

et al. 2009

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We have for the first time developed two ligand-assisted Cu(I)-catalyzed sequential intra- and intermolecular S-arylations leading to the direct synthesis of arylthiobenzothiazoles in one pot without an inert atmosphere. Low catalyst loading, inexpensive metal catalyst and ligand, lower reaction temperature, and shorter reaction times make this method superior to all reported methods for the synthesis of arylthiobenzothiazole.

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Some Thiazolylthio Hydroquinones

Cited by 5 publications

References 0 publications

Functional, Redox-Responsive Poly(phenylene sulfide)-Based Gels

Functional, Redox-Responsive Poly(phenylene sulfide)-Based Gels

Asymmetric Tandem Michael‐Aldol Reactions between 3‐Cinnamoyloxazolidine‐2‐thiones and Aldehydes

Intra- and Intermolecular C−S Bond Formation Using a Single Catalytic System: First Direct Access to Arylthiobenzothiazoles

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