Oligomerization and Polymerization of NCAs: Chemical Aspects

Kricheldorf, Hans R.

doi:10.1007/978-3-642-71586-0_3

Cited by 10 publications

(9 citation statements)

References 237 publications

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“…The water‐ and alcohol‐tolerant property of polymerizations of AA‐NPCs is proved by experimental data, though contradicting with the nucleophile‐sensitive nature of AA‐NCAs, the in situ generated intermediate of AA‐NPCs. Hydroxyl groups are reported to be able to initiate the ROPs of AA‐NCAs . Thus, mechanism study is further conducted to confirm the hydroxyl tolerance of AA‐NPCs.…”

Section: Resultssupporting

confidence: 66%

“…Hydroxyl groups are reported to be able to initiate the ROPs of AA-NCAs. [25][26][27] Thus, mechanism study is further conducted to confirm the hydroxyl tolerance of AA-NPCs. Amine, water, and alcohol form six-member ring with AA-NPC monomers (1a and 1b in Scheme S1).…”

Section: Mechanism Of Hydroxyl Tolerance Of Aa-npcsmentioning

confidence: 99%

“…The highly activated nature of AA‐NCA ensures its ROP highly productive and precisely controllable on molecular weights (MWs), however, which also makes AA‐NCA very sensitive to nucleophiles. Articles have been reported that water and alcohols are capable to initiate the ROPs of AA‐NCAs, which leads to ill‐controlled polymerizations . Hence, there are very limited results about the synthesis of AA‐NCAs containing unprotected hydroxyl group(s), including phenolic hydroxyl group(s), let alone their controlled polymerizations.…”

Section: Introductionmentioning

confidence: 99%

“…Articles have been reported that water and alcohols are capable to initiate the ROPs of AA-NCAs, which leads to ill-controlled polymerizations. [25][26][27] Hence, there are very limited results about the synthesis of AA-NCAs containing unprotected hydroxyl group(s), including phenolic hydroxyl group(s), let alone their controlled polymerizations. To achieve the synthesis of functional polypeptides aforementioned, two strategies are widely applied, which are postfunctionalization and protection/deprotection of the active side groups.…”

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confidence: 99%

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Hydroxyl‐tolerated polymerization of N‐phenoxycarbonyl α‐amino acids: A simple way to polypeptides bearing hydroxyl groups

Yang

Bai

Ling

et al. 2019

J. Polym. Sci. Part A: Polym. Chem.

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Differing from the moisture‐sensitive α‐amino acid N‐carboxyanhydrides (AA‐NCAs) monomers, N‐phenoxycarbonyl α‐amino acids (AA‐NPCs) can be prepared and stored in open air. In this contribution, we report that the controlled polymerizations of AA‐NPC monomers of O‐tert‐butyl‐dl‐serine (BRS‐NPC), Nε‐benzyloxycarbonyl‐l‐lysine (ZLL‐NPC) and Nε‐trifluoroacetyl‐l‐lysine (FLL‐NPC) initiated by amines are surprisingly able to tolerate common nucleophilic impurities such as water and alcohols at a level of monomer concentration. The structures of polypeptides synthesized in the presence of water or alcohols agree well with the designed ones in the case of repeated chain extensions. Detailed mechanism study and density functional theory calculation reveal that the low concentration of AA‐NCA and the high activity of amines are the key factors to the controllability of AA‐NPC polymerizations. The water‐ and alcohol‐tolerant property in polymerizations of AA‐NPCs encourages the following studies on unprotected (phenolic) hydroxyl groups containing AA‐NPCs. The controllable polymerizations of N‐phenoxycarbonyl l‐tyrosine (LT‐NPC) and N‐phenoxycarbonyl S‐(3‐hydroxypropyl)‐l‐cysteine (HLC‐NPC) initiated by amines are confirmed and reported for the first time, which extends the library of AA‐NPCs and polypeptides as well. All the universality of library, the convenience of monomer preparation, and the controllability and water‐ and alcohol‐tolerant property of polymerization of AA‐NPCs significantly enhance the feasibility of polypeptide synthesis, making AA‐NPC approach a promising synthetic method of polypeptides. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 907–916

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Section: Resultssupporting

confidence: 66%

Section: Mechanism Of Hydroxyl Tolerance Of Aa-npcsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

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Hydroxyl‐tolerated polymerization of N‐phenoxycarbonyl α‐amino acids: A simple way to polypeptides bearing hydroxyl groups

Yang

Bai

Ling

et al. 2019

J. Polym. Sci. Part A: Polym. Chem.

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“…Nevertheless, a brief explanation will be provided. On the one hand, the polymerization via the “amine mechanism” (which is also known under the name “protic mechanism”) is initiated by protic nucleophiles such as primary amines and was first reported by Wessely and by Watson et al [ 57 ]. In this mechanism, shown in Figure 8 , the primary amine reacts with the C-5 in the NCA monomer.…”

Section: Polymerization Of α-Amino Acid N -Carbmentioning

confidence: 99%

Strategies to Fabricate Polypeptide-Based Structures via Ring-Opening Polymerization of N-Carboxyanhydrides

2017

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Abstract:In this review, we provide a general and clear overview about the different alternatives reported to fabricate a myriad of polypeptide architectures based on the ring-opening polymerization of N-carbonyanhydrides (ROP NCAs). First of all, the strategies for the preparation of NCA monomers directly from natural occurring or from modified amino acids are analyzed. The synthetic alternatives to prepare non-functionalized and functionalized NCAs are presented. Protection/deprotection protocols, as well as other functionalization chemistries are discussed in this section. Later on, the mechanisms involved in the ROP NCA polymerization, as well as the strategies developed to reduce the eventually occurring side reactions are presented. Finally, a general overview of the synthetic strategies described in the literature to fabricate different polypeptide architectures is provided. This part of the review is organized depending on the complexity of the macromolecular topology prepared. Therefore, linear homopolypeptides, random and block copolypeptides are described first. The next sections include cyclic and branched polymers such as star polypeptides, polymer brushes and highly branched structures including arborescent or dendrigraft structures.

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Divergent Synthesis of γ‐Amino Acid and γ‐Lactam Derivatives from meso‐Glutaric Anhydrides

Smith

Craig

Connon

2020

Chemistry A European J

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The first divergents ynthesis of both g-amino acid and g-lactam derivativesf rom meso-glutaric anhydrides is described. The organocatalytic desymmetrisation with TMSN 3 relies on controlled generation of an ucleophilic ammoniuma zide species mediated by ap olystyrene-bound base to promote efficients ilylazidation. After Curtiusr earrangemento ft he acyl azide intermediatet o access the corresponding isocyanate, hydrolysis/alcoholysis provided uniformlyh igh yields of g-aminoa cids and their N-protected counterparts. The same intermediates were shown to undergo an unprecedented decarboxylation-cyclisation cascade in situ to provide synthetically useful yields of g-lactamd erivatives without using anyf urther activating agents. Mechanistic insights invoke the intermediacy of an unconventional g-N-carboxyanhydride (g-NCA) in the latter process. Among the examples prepared using this transformation are 8APIs/moleculeso f considerable medicinali nterest.

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Oligomerization and Polymerization of NCAs: Chemical Aspects

Cited by 10 publications

References 237 publications

Hydroxyl‐tolerated polymerization of N‐phenoxycarbonyl α‐amino acids: A simple way to polypeptides bearing hydroxyl groups

Hydroxyl‐tolerated polymerization of N‐phenoxycarbonyl α‐amino acids: A simple way to polypeptides bearing hydroxyl groups

Strategies to Fabricate Polypeptide-Based Structures via Ring-Opening Polymerization of N-Carboxyanhydrides

Divergent Synthesis of γ‐Amino Acid and γ‐Lactam Derivatives from meso‐Glutaric Anhydrides

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