Maleimide Functional Groups Research Articles

Controlled Diels−Alder Reactions Used To Incorporate Highly Efficient Polyenic Chromophores into Maleimide-Containing Side-Chain Polymers for Electro-Optics

Using an in situ Diels−Alder (DA) “click chemistry” strategy for reactions between anthracene and maleimide functional groups, two prototypes of novel nonlinear optical (NLO) side-chain polymers (PMI-A7 and PMI-B7) containing highly hyperpolarizable but chemically sensitive phenyltetraene-based chromophores were synthesized and their nonlinear optical and thermal properties were characterized. Through rational material design, these NLO side-chain polymers exhibited good processibility, large electro-optic (E-O) coefficients (r33, of up to 263 and 287 pm/V at 1.31 μm wavelength respectively), and excellent temporal stability. These combined properties make them promising materials for E-O device applications. Compared to PMI-B7, PMI-A7 exhibited significantly enhanced temporal stability (87% of the initial r33 values was retained after 550 h at 85 °C) and solvent resistance, which was attributed to slight cross-linking from the side reaction between maleimide and phenyltetraenic chromophore moieties. This...

Functionalized cationic (η 6-arene)ruthenium(II) complexes for site-specific and covalent anchoring to papain from papaya latex. Synthesis, X-ray structures and reactivity studies

The cationic (η 6-arene)ruthenium complexes 6– 9 containing a chloroacetamide or a maleimide functional group on the arene ligand were synthesized and successfully used to introduce ruthenium(II) species to the active site of the cysteine endoproteinase papain in a site-directed and covalent fashion as shown by enzymatic and ESI-MS studies.

Synthesis and Characterization of Polymeric Thioxanthone Photoinitatiors via Double Click Reactions

Macrophotoinitiators containing thioxanthone (TX) moieties as side chains were synthesized by using “double click chemistry” strategy; combining in-situ 1,3-dipolar azide−alkyne [3 + 2] and thermoreversible Diels–Alder (DA) [4 + 2] cycloaddition reactions. For this purpose, thioxanthone−anthracene (TX−A), N-propargyl-7-oxynorbornene (PON), and polystyrene (PS) with side-chain azide moieties (PS−N3) were reacted in N,N-dimethylformamide (DMF) for 36 h at 120 °C. In this process, PON acted as a “click linker” since it contains both protected maleimide and alkyne functional groups suitable for 1,3-dipolar azide−alkyne and Diels−Alder click reactions, respectively. This way, the aromacity of the central phenyl unit of the anthracene moiety present in TX−A was transformed into TX chromophoric groups. The resulting polymers possess absorption characteristics similar to the parent TX. Their capabilities to act as photoinitiator for the polymerization of mono- and multifunctional monomers, namely methyl methacrylate (MMA) and 1,1,1-tris(hydroxymethyl)propane triacrylate (TPTA) were also examined.

Amphiphilic polymer brushes with alternating PCL and PEO grafts through radical copolymerization of styrenic and maleimidic macromonomers

Synthesis of a novel amphiphilic polymer brush with a sequence of alternating poly(ɛ-caprolactone) (PCL) and poly(ethylene oxide) (PEO) side chains through grafting-through approach is reported. This strategy consists of two steps: first, a PCL macromonomer carrying maleimide functional group (MI-PCL) and a PEO macromonomer with vinylbenzyl group (St-PEO) were prepared; then a conventional radical copolymerization of the MI-PCL and the St-PEO macromonomers was carried out to obtain the proto-type polymer brush. The reactivity ratios of two macromonomers were studied and the alternating sequence structure was proved.

Improved synthesis of DCDHF fluorophores with maleimide functional groups

A group of dicyanodihydrofuran (DCDHF) fluorophores with thiol-reactive maleimide functionality has been synthesized. One of the methods involves aromatic nucleophilic substitution reaction between an arylfluoride containing DCDHF and an amine containing protected maleimide. An alternative and generally useful method involves combination of the Mitsunobu reaction of a DCDHF-OH with a furan or 2-methylfuran protected maleimide and then subsequent retro Diels–Alder reaction.

Anthracene−Maleimide-Based Diels−Alder “Click Chemistry” as a Novel Route to Graft Copolymers

Using the Diels−Alder (DA) “click chemistry” strategy between anthracene and maleimide functional groups, two series of well-defined polystyrene-g-poly(ethylene glycol) (PS-g-PEG) and polystyrene-g-poly(methyl methacrylate) (PS-g-PMMA) copolymers were successfully prepared. The whole process was divided into two stages: (i) preparation of anthracene and maleimide functional polymers and (ii) the use of Diels−Alder reaction of these groups. First, random copolymers of styrene (S) and chloromethylstyrene (CMS) with various CMS contents were prepared by the nitroxide-mediated radical polymerization (NMP) process. Then, the choromethyl groups were converted to anthryl groups via the etherifaction with 9-anthracenemethanol. The other component of the click reaction, namely protected maleimide functional polymers, were prepared independently by the modification of commercially available poly(ethylene glycol) (PEG) and poly(methyl methacrylate) (PMMA) obtained by atom transfer radical polymerization (ATRP) usin...

Utility of thiol-cross-linked fluorescent dye labeled terminators for DNA sequencing.

Dipivaloyl-5-carboxyfluorescein N-hydroxysuccinimidyl ester 1 and 5-propargylamino-2',3'-dideoxyuridine triphosphate 5 were modified with maleimide, haloacetamide, and sulfhydryl reactive functional groups to participate in cross-conjugation reactions via sulfide bonds to generate fluorescently labeled, thioether cross-conjugated terminators 10 and 11. Their DNA sequencing potential was compared with an amide cross-conjugated terminator 13, synthesized by directly coupling 5-carboxyfluorescein NHS ester with 18-ddUTP 9. These terminators (10, 11, and 13) in combination with the Thermo Sequenase II DNA polymerase, in thermal cycle sequencing experiments, revealed that the thioether cross-conjugated terminator 10 and amide cross-conjugated terminator 13 served as good terminating substrates, generating satisfactory single-color gel images and electropherograms, while the other thioether cross-conjugated and maleimide derived one 11 underwent unexpected pH and temperature induced decomposition without showing fluorescent signatures for incorporation.

Carbohydrate-directed conjugation of cobra venom factor to antibody by selective derivatization of the terminal galactose residues.

Cobra venom factor (CVF) can cause cell death by complement-mediated bystander cell lysis. Several studies have investigated CVF for application in cancer therapy by conjugating CVF to antibodies against tumor cell surface-specific antigens via the side-chain amino acid residues. In most cases, the activity of CVF was markedly impaired, presumably by modification of the factor B binding domain due to random derivatization. Since CVF is a glycoprotein and its oligosaccharide chains are distal to the factor B binding domain, coupling of CVF to antibodies through its oligosaccharide chains is expected to yield immunoconjugates with retention of CVF activity and elimination of the immunoreactivity of the terminal alpha-galactosyl residues. In this study, we investigated the carbohydrate site-directed conjugation of CVF to a monoclonal IgG specific to a cell-surface antigen of human ovarian cancer cells. The terminal galactosyl residues of CVF were selectively modified at C-6 by treatment with galactose oxidase, and the generated aldehyde groups were derivatized in situ with hydrazides containing either protected thiol or maleimide functional groups. The CVF derivatives were allowed to react with thiol groups introduced to the antibody by derivatization with 2-iminothiolane to yield carbohydrate site-directed CVF-antibody conjugates. In both cases, 30-40% of the antibody cross-linked to CVF to yield predominantly monovalent CVF-antibody conjugates. The purified immunoconjugates retained 70-75% of CVF activity and significant level of antigen-binding capacity. This is the first study to exploit the oligosaccharide chains of CVF for the preparation of active immunoconjugates.

Novel high temperature resins based on bis(4‐maleimido‐phenyl)methane

AbstractA novel high temperature thermosetting resin system based on the addition polymerization of bis (4‐maleimidophenyl)methane and o, o′‐diallyl‐bisphenol A is presented in this paper. This system offers the combination of easy solventless processing and the high temperature and toughness performance characteristics demanded for the fabrication of C‐fibre laminates. The mechanism of the polyaddition reaction is unusual. In a first step an ENE addition reaction of the maleimide to the allyl group occurs to give a 1:1 adduct with a propenyl phenol type of structure. This is then followed by a Diels‐Alder addition reaction of another maleimide functional group to the ENE adduct (by the so‐called Wagner‐Jauregg reaction) to give a densely crosslinked polymer with glass transition temperatures well over 280°C.

Rheokinetic studies of the synthesis and properties of elastomers based on the oligodiene dihydrazides and unsaturated dicarboxylic imides

Rheokinetic methods were used to investigate the synthesis of elastomers from oligoisoprene dihydrazide and maleic acid bis-imides. The effect of the bis-imide structure, temperature-time parameters and the ratio of initial compounds in the rheokinetics of synthesis of cured compositions and on their deformation-strength properties has been investigated. A crosslinking mechanism is proposed, taking account of the reaction between terminal hydrazide and maleimide functional groups, as well as homopolymerization of maleimide. The feasibility of reinforcement of the obtained elastometer by active fillers has been ascertained.