Maleimides preparation

Free Radical Copolymerization of 4,7-Dihydro-1,3-dioxepins with Maleic Anhydride and Maleimides Preparation of Head-to-Head Poly(4-hydroxycrotonic acid) and Poly( -crotonolactone)... 

Imides are diacyl derivatives of ammonia or primary amines. The reaction is similar in its scope and mechanism to the acetylation of aniline or 1,4-phenylene-diamine presented in Experiments [23A] and [23B], As illustrated in the present experiment, cyclic anhydrides produce cyclic imides. Cyclic anhydrides are prepared in Experiments [25A] and [25B], Derivatives of imides have been suggested for use in the treatment of arthritis, tuberculosis, and epilepsy. Several also have been found to be growth stimulants. Imide-based polymers are used in many applications, including fire-resistant woven fabrics. The N-phenyl-maleimide prepared in this experiment is also a good dienophile in the Diels-Alder reaction (see Experiments [14] and [15]), and in fact has been used as a reagent to characterize 1,3 dienes. 

Bis(maleimides) prepared from aromatic diamines (benzidine, p-phenylcne-diamine, o-tolidine, o-anisidine) were condensed with 1,8-diphenyloctatetraene and related bis(dienes). Polymers that softened above 300°C with molecular weights of approximately 3000 were obtained (18). A Diels-Alder polymerization has been described that yields a ladder polymer. The cyclic oligomeric esters [13] and [14] give low molecular weight polymer when heated in toluene (7). p-Benzoquinone has also been polymerized with [14]. A chloroform-soluble product with a molecular weight of about 2000 was obtained (7). 

V-Alkyl or A/-aryl succinimides can be prepared from the corresponding amines (107) or from succinic anhydride, ammonia, and the corresponding alcohol (108). Succinimides are also obtained by vapor-phase hydrogenation of the corresponding maleimides ia the presence of a catalyst (109). 

The original compound, maleimide (2,5-dioxo-A -pyrroline), is synthesized by the cyclo-condensation of ammonia and maleic acid. Similarly, primary amine is added to maleic anhydride, followed by cyclocondensation, to form N-substituted maleimide (Fig. 2). This reaction is applied to the preparation of bis-maleimides (BMl) [1]. At first, BMI was used as a crosslinking agent for natural rubber (NR). An o-dichlorobenzene solution of NR was crosslinked by BMI at I08-150°C in the presence of peroxides. The radicals generated from peroxides react with the double bonds of both BMI and NR [ 1 ]. 

As already mentioned, aromatie polymers are thermally stable but aliphatic portions of them are not as thermally stable. Typical maleimide resins have aliphatic units. This is inevitable because the Michael addition was used to prepare the maleimide-based oligomers. On the other hand, if an adhesive consists of a linear thermoplastic polymer, it is not usable at temperatures above its softening temperature. Introdueing chemical crosslinking is one way to prevent thermal weakening of a material. 

Phosphorus containing poly(maleimide-amines) were synthesized from N,N -bisdichloromaleimido-3,3 -diphenyl alkylphosphine oxides and aromatic diamines or piperazine [144]. The polymers prepared from piperazine are soluble in DMF, DM AC, DMSO, etc., but have poor thermal stability and flame retardancy. 

The procedure described here for the preparation of succinimide silver salt is a modification of one reported for the formation of the silver derivative of maleimide. The alkylation step is modeled after the procedure of Comstock and Wheeler/ who prepared 2-ethoxypyrrolin-5-one in unspecified 3deld, and is an improvement over a later procedure developed in the laboratories of the submitters/ The general scheme has been successfully applied to the preparation of a variety of 2-ethoxypyrrolin-5-ones (Table 1) as well as 6-ethoxy- and 6-propoxy-4,5-dihydro-2(3H)-pyridone from the corresponding five- and six-membered cyclic imides/... 

The aqueous Diels-Alder reaction has also been used for bioconjugate studies. A Diels-Alder reaction of diene oligonucleotides with maleimide dieneophiles was used to prepare oligonucleotide conjugates in aqueous media under mild conditions (Eq. 12.39).102 A Diels-Alder-type cycloaddition of an electronically matched pair of saccharide-linked conjugated dienes and a dienophile-equipped protein was the... 

A library of fifteen 6,7,9,9a-tetrahydro-57/-pyrazolo[l,2-tf]pyrrolo[3,4-ir]pyrazole-l,3,5(2/7,3a7/)-triones 712 was prepared by combinatorial stereoselective cycloadditions of compounds 320 to A-substituted maleimides. 

Fused octahydrocycl[3.2.2]azines of the type 392 are obtained by tandem cycloadditions of pyridinium phenacylide with iV-substituted maleimides <1989JOC420>, and other types of fused octahydrocyclazines, viz. 394, result from the attempted preparation of the enamines 393, since these are unstable and undergo intramolecular acylation <1999T1763> (Scheme 114). 

Houseman BT, Gawalt ES, Mrksich M (2003) Maleimide-functionalized self-assembled monolayers for the preparation of peptide and carbohydrate biochips. Langmuir 19 1522-1531... 

Dissolve BMPA in DMSO or DMF to prepare a stock solution at a higher concentration such that adding an aliquot of this solution to the protein solution will result in the desired molar excess of the maleimide over the concentration of thiols present. 

Add at least a 10-fold molar excess of NEM over the amount of sulfhydryls present in the reaction. Alternatively, add an equal mass of NEM to the amount of macromolecule present. To facilitate the addition of a small quantity of reagent, a more concentrated stock solution may be prepared in buffer and an aliquot added to the reaction medium. Make the stock solution up fresh, and use it immediately to prevent loss of activity due to maleimide group breakdown. 

Dissolve NHS-PEGg-maleimide (MW 601.6) into DMSO at a concentration of 20mM. Short, PEG-type crosslinkers often exist as a thick oily mass, and preparing the solution typically involves dissolving an entire vial of the compound into DMSO to determine accurately the required concentration. Use only dry DMSO to avoid hydrolysis of the NHS ester. 

Coupling of affinity molecules to surfaces also can be enhanced by the use of discrete PEG linkers. Nishimura et al. (2005) modified an amino surface with a NHS-PEG -maleimide crosslinker to create a hydrophilic self-assembled monolayer (SAM) surface that was thiol reactive for the conjugation of sulfhydryl-modified RNAs. This array then was used to investigate the binding specificity of synthetic kanamycins with selected RNA sequences to prove the specific interaction of ribosomal RNA with this molecule. The PEG linkers on surfaces provide lower nonspecific binding character than alkyl linkers, when preparing SAM surfaces for affinity interactions. 

In a fume hood, dissolve the NHS-PEG -maleimide compound of choice in a dry, water-miscible organic solvent to make a concentrated stock solution. For instance, to prepare a lOOmM solution of the NHS-PEGg-maleimide reagent (MW 601.6), dissolve an entire 100 mg vial of the crosslinker in 1.66 ml of DMAC (dry DMSO or DMF work well, too). 

Prepare a stock solution of the maleimide-PEG -biotin compound in DMAC, DMSO, or DMF (pure and dry solvents only) at a concentration of 10-20 mM. 

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