Ketene acetal monomers: Synthesis and characterization

Crivello, James V.; Malik, Ranjit; Lai, Yi‐Chun

doi:10.1002/(sici)1099-0518(19961115)34:15<3091::aid-pola1>3.0.co;2-0

Cited by 27 publications

(18 citation statements)

References 15 publications

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“…This step was carried out following procedures described previously. 22,23,25 The PTSA catalyzed reaction cleanly produced at room temperature the diorthoester 11 (32%). To avoid extensive purification on silica gel that induced orthoester hydrolysis, we performed the last reduction step in the presence of a resin-supported triphenylphosphine that accomplished the Staudinger's azide reduction in a quantitative yield affording the pH-sensitive tetraether 3.…”

Section: Resultsmentioning

confidence: 99%

Synthesis of a novel archaeal tetraether-type lipid containing a diorthoester group as a helper lipid for gene delivery

Barbeau

Belmadi

Montier

et al. 2016

Tetrahedron Letters

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International audienceAs an alternative to recombinant virus, synthetic carriers are widely developed for providing efficient and safe DNA delivery. To reach the nucleus where nucleic acid (NA) constructs are transcripted, chemical complexes have to overcome serious cellular traps such as endosomal escape and intracellular trafficking. Here, the design and the multi-step synthesis of a stabilizing tetraether lipid analogue of archaeal counterparts containing a diorthoester moiety in the middle of the bridging chain were described. The key step involved a double coupling reaction between two diether alcohols and a diketene acetal. Under aqueous acidic conditions, the diorthoester function of the tetraether lipid can be hydrolysed to yield two monopolar diether lipids. Applied to gene delivery in association with a cationic lipid, this new helper bipolar tetraether lipid led to lipid-DNA complexes with sizes and potential zeta values depending on the charge ratios (+/-). In addition, preliminary in vitro transfection assays supported the interest of these novel bipolar lipid-based lipoplex formulations compared to standard Lipofectamine-based formulations. © 2016 Elsevier Ltd. All rights reserved

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Section: Resultsmentioning

confidence: 99%

Synthesis of a novel archaeal tetraether-type lipid containing a diorthoester group as a helper lipid for gene delivery

Barbeau

Belmadi

Montier

et al. 2016

Tetrahedron Letters

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“…The following general connections can be given: a) the ring-opening tendency increases with the ability of the substituents in 4-and 5-position to stabilize cations (Ph A Et A Me A CH 2 Cl), b) bulky substituents on the exo-methylene group favor ring-opening (Et A Me) but will simultaneously cause decreasing yields and lower molecular weights, c) resonance stabilization always increases the chance for ring-opening. However, all of the above mentioned factors can work against each other, as it has also been shown in a very clear way [51].…”

Section: -Methylene-13-dioxolanesmentioning

confidence: 93%

“…Recently Crivello and coworkers have found access to a series of five-and six-membered ketene acetals (33 a -e, 34 a -f) with alkyl-groups attached to the exo-methylene group [51,52]. As it is further known, ketene acetals having outer substitution shouldn't be able to undergo radical induced polymerizations or the radical attack should at least be retarded.…”

Section: -Methylene-13-dioxolanesmentioning

confidence: 99%

“…Crivello et al have reported the photopolymerization of 2-ethylidene-1.3-dioxane 82 and 2-ethylidene-4-methyl-1.3-dioxane 83, respectively [51,52]. Beside the general considerations given there concerning the role of outer substituents on the polymerization ability both monomers were found to undergo 45% (for 82) and 81% ring-opening (for 83).…”

Section: 3-dioxanesmentioning

confidence: 99%

“…Whenever substances with outer substitution on the methylene group have to be synthesized, the standard methods of elimination tends to fail in most cases. A more favorable synthetic method has recently been described by Crivello et al [51]. Triphenylphosphine ruthenium dichloride (Ph 3 P) 3 RuCl 2 was found to be a suitable catalyst for the isomerization of substituted vinyl acetals into ketene acetals similar to the rearrangement reactions of: allyl ethers r 1-propenylethers CH 2 2CH1CH(R9)1OR e CH 3 1CH2C(R9)OR crotyl ethers r 1-butenylethers CH 3 1CH2CH1CH (R9)1OR e CH 3 1CH 2 1CH2C(R9)1OR…”

Section: Synthetic Aspectsmentioning

confidence: 99%

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Ring-opening polymerization of heterocycles bearing substituted and unsubstituted exo-methylene groups - a review

Klemm

Schulze

1999

Acta Polym.

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Monocyclic monomers bearing exo‐methylene groups are likely to undergo ring‐opening polymerization under the conditions of radical or cationic initiation. Several structural features will determine the course of reaction after initiation by species that exclusively attack the exo‐methylene functionality. Reviewing some of the most common classes of monocyclic heterocycles it becomes obvious that a monomer has to meet certain structural preconditions that makes them suitable for isomerizations. Among the considered heterocycles there are some types of monomers possessing an outstanding ring‐opening behavior following polymerization mechanisms free from side‐reactions. The combination of strain release due to ring‐opening isomerization, an energy decrease in the transition state caused by the formation of carbonyl‐functionalities and an appropriate stabilization of the growing chain end by steric and electronic effects may lead to clear ring‐opening mechanisms. However, this property remains restricted to only some special monomers with simple aromatic substituents being attached to the cycle. Hence a variety of cyclic ketene acetals, enolethers, (meth)acrylates, carbonates, lactones and lactames have been chosen in order to demonstrate both the possibilities and limits of ring‐opening.

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