Pyridinedithioesters as Heterodienophiles:  Application to the Synthesis of Aprikalim

Bastin, Reyhan; Al‐Badri, Hashim; Gaumont, and Annie-Claude; Gulea, Mihaela

doi:10.1021/ol052942k

Cited by 41 publications

(28 citation statements)

References 16 publications

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“…It is known that dithioesters similar in structure to 1a,b show a high Diels-Alder reactivity. 38,39 Their ability to be used as controlling agents in the RAFT polymerization of styrene has been shown to be not as effective as most of the more common RAFT agents. 40,41 However, for the molecular weight range utilized in the present study, compounds 1a,b adequately control the polymerization of styrene in addition to being effective heterodienophiles; thus, they fulfill both purposes.…”

Section: Resultsmentioning

confidence: 99%

“…This can be achieved by using ZnCl 2 as a Lewis acid in the case of the phosphoryl Z-group 38 and by trifluoroacetic acid (TFA) as a Brønsted acid in the case of the pyridinyl Z-group. 39 Although achieving the same effect, the catalysts were selected on the basis of the nature of their interaction with the RAFT Z-group: the ZnCl 2 chelates with the oxygen on the phosphinyl group, whereas the H + from the TFA protonates the nitrogen on the pyridinyl group. In order to verify the versatility of this method, we herein report the synthesis of star polymers by a combination of RAFT chemistry and the HDA cycloaddition.…”

Section: Introductionmentioning

confidence: 99%

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Reversible Addition Fragmentation Chain Transfer (RAFT) and Hetero-Diels−Alder Chemistry as a Convenient Conjugation Tool for Access to Complex Macromolecular Designs

et al. 2008

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The combination of RAFT chemistry and the hetero-Diels-Alder (HDA) cycloaddition was successfully utilized in the synthesis of poly(styrene) (PS) star polymers with up to 4 arms. This variant of the "coupling onto" method of star polymer synthesis was investigated for two different RAFT end groups (diethoxyphosphoryldithioformate and pyridin-2-yldithioformate) and coupling agents bearing 2, 3, or 4 diene functional groups. When a diethoxyphosphoryldithioformate terminated polymer was reacted with the 2-, 3-, and 4-fold functionalized coupling agents, the yields of 2-arm star, 3-arm star, and 4-arm star polymers were 81%, 77%, and 65%, respectively, and when a pyridin-2-yldithioformate terminated polymer was reacted with the same coupling agents, the yields of 2-arm star, 3-arm star and 4-arm star polymers were 91%, 86% and 82% respectively. The HDA coupling reaction was monitored via UV/vis spectroscopy from the perspective of the RAFT end group as well as by 1 H NMR spectroscopy from the perspective of the diene functionality. The results of these investigations indicated that the phosphoryldiethoxydithioformate terminated polymer achieves 92% conversion within a 24 h time frame and the pyridin-2-yldithioformate terminated polymer achieves 96% conversion in 10 h. The 4-arm star polymers were also subjected to high-temperature environments, and GPC measurements indicated that complete cleavage of all 4 arms from the core was achieved in 24 h at 160°C.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Reversible Addition Fragmentation Chain Transfer (RAFT) and Hetero-Diels−Alder Chemistry as a Convenient Conjugation Tool for Access to Complex Macromolecular Designs

et al. 2008

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“…[32][33][34][35] Therefore BF 3 etherate as well as ZnCl 2 were utilized as Lewis acids with a amount of 0.5 eq per functional unit thioamide. Addition of BF 3 resulted immediately in a brown precipitation and further degradation.…”

Section: Synthesis and Characterization Of 3b5 And The Oligomeric Spementioning

confidence: 99%

Reversible oligomerization of 3-aryl-2-cyanothioacrylamides via [2_s + 4_s] cycloaddition to substituted 3,4-dihydro-2H-thiopyrans

Kötteritzsch

Bode

Yildirim

et al. 2015

Designed Monomers and Polymers

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(2015) Novel difunctional monomers are synthesized which are able to dimerize as well as oligomerize via the hetero-DielsAlder (HDA) mechanism. These monomers are based on 3-aryl-2-cyanothioacrylamides, which are used as functional units for the HDA reaction to form 3,4-dihydro-2H-thiopyrans. Different substituents of the aromatic ring are utilized to shift the equilibrium to the dimeric or oligomeric species. The HDA reaction is reversible and can be influenced by the temperature as well as the concentration. In contrast, the N,N-dimethylthioacrylamide analogues do not dimerize or the dimerization is not reversible. The most promising compound is furthermore investigated in detail by 1 H NMR spectroscopy to elucidate the dimerization kinetics. In addition, a difunctional molecule is able to oligomerize reversibly, as confirmed by means of 1 H NMR, size exclusion chromatography (SEC), and ESI MS measurements. A respective alcohol is employed as initiator for the ring-opening polymerization of L-lactide resulting in an end-functional polymer that undergoes reversible dimerization as confirmed by SEC measurements.

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“…Die resultierenden GPC-Elugramme waren identisch mit denen einer frisch präparierten Mischung aus 4 und 1 a und stimmten mit den Elugrammen der individuellen Segmente überein. Es wurde berichtet, dass der Pyridinyldithioester mit Butadienderivaten ohne Zugabe von Katalysator reagieren kann; [28] Ausgangsmaterialien 4 und 1 a zusammen mit denen der Reaktionsmischung nach 10 s sowie 1, 5 und 10 min. Eine Auswertung der Abbildung 2 zeigt eindeutig, dass der Groß-teil der Blockcopolymere innerhalb der ersten 10 s der Reaktion gebildet wird.…”

Section: Polymerunclassified

Ultraschnelle Klickkonjugation von makromolekularen Bausteinen bei Raumtemperatur

et al. 2009

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Blockcopolymere in Sekundenschnelle: Eine katalysatorfreie Klickkonjugation einzelner Polymerketten gelingt bei Raumtemperatur mithilfe neuer, durch ATRP hergestellter Polymere mit Cyclopentadienyl‐Endfunktionen. Dabei werden diese Polymere durch eine äußerst schnelle heterogene Diels‐Alder‐Cycloaddition mit durch RAFT hergestellten Makromolekülen umgesetzt, die elektronenarme Dithioester‐Endfunktionen aufweisen.

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Pyridinedithioesters as Heterodienophiles: Application to the Synthesis of Aprikalim

Cited by 41 publications

References 16 publications

Reversible Addition Fragmentation Chain Transfer (RAFT) and Hetero-Diels−Alder Chemistry as a Convenient Conjugation Tool for Access to Complex Macromolecular Designs

Reversible Addition Fragmentation Chain Transfer (RAFT) and Hetero-Diels−Alder Chemistry as a Convenient Conjugation Tool for Access to Complex Macromolecular Designs

Reversible oligomerization of 3-aryl-2-cyanothioacrylamides via [2_s + 4_s] cycloaddition to substituted 3,4-dihydro-2H-thiopyrans

Ultraschnelle Klickkonjugation von makromolekularen Bausteinen bei Raumtemperatur

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Pyridinedithioesters as Heterodienophiles: Application to the Synthesis of Aprikalim

Cited by 41 publications

References 16 publications

Reversible Addition Fragmentation Chain Transfer (RAFT) and Hetero-Diels−Alder Chemistry as a Convenient Conjugation Tool for Access to Complex Macromolecular Designs

Reversible Addition Fragmentation Chain Transfer (RAFT) and Hetero-Diels−Alder Chemistry as a Convenient Conjugation Tool for Access to Complex Macromolecular Designs

Reversible oligomerization of 3-aryl-2-cyanothioacrylamides via [2s + 4s] cycloaddition to substituted 3,4-dihydro-2H-thiopyrans

Ultraschnelle Klickkonjugation von makromolekularen Bausteinen bei Raumtemperatur

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Reversible oligomerization of 3-aryl-2-cyanothioacrylamides via [2_s + 4_s] cycloaddition to substituted 3,4-dihydro-2H-thiopyrans