Maleic-imide groups

Such compounds are treated as hydroxyl compounds even if their dominant tautomeric form is the keto tautomer. Reduction usually takes place either in the nucleus or at the carbonyl group. Simple examples of the first type are maleic imide [393, 394] and hydra-zide [395] in many other examples a second reduction leads to a ring contraction. Reduction of the keto group leads to a hydroxyl group in many cases water is eliminated and a further reduction takes place. An example of this is the reduction of AT-methylsuc-cinimide to AT-methylpyrrolidone [396]. Oxidation of hydroxy-substituted dihydrohetero-cycles may introduce a double bond an example is the oxidation of 1,2-dihydro-3-methoxycarbonyl-4-hydroxyquinoline in AcOH/7-BuOH to 1,4-dihydro-4-oxo-3-methox-ycarbonylquinoline [397]. The use of pyrrolidone as a probase is discussed in Chapter 30 [398]. 

Remarkably N-phenyl maleic imide (34) reacted completely stereoselectively in the one-pot three-component reaction with 14 and 31a resulting in the formation of nitroso acetal (35) as one single diastereomer in 90 % yield (Scheme 9.12). This diastereomer arose from a completely endo-selective [4 + 2] and a completely endo-selective [3 + 2] cycloaddition following an anti approach with respect to the pyr-idyl group. 

The structure of EPDM grafted onto polyamide 66 was analysed by FTIR spectroscopy. Evidence indicated the presence of cyclic imide groups, derived from grafted maleic anhydride groupings (229). 

With the polyimides produced in situ, the imide group is simultaneously formed with the polymer. Synthesis and processing difficulties with polyimides formed in situ have led to the development of monomers and prepolymers with preformed imide groups. For example, maleic anhydride converts to what is known as bismaleimides with suitable diamines... 

Various polymerization route with unique starting monomer [64] have been developed, e.g., topochemical poly(diacetylene) synthesis with pyrrole-, thiophene-, -Si-groups dienophilic addition of maleic imides, Diels-Alder polymers via cyclopentadienone derivatives. 

Another example relates to the plasma polymerization of maleic anhydride on silicon substrates [55]. After functionalization of the anhydride groups of the polymer with dienophile groups such as allyl amine groups, bicyclo[2.2.1]hept-2-ene groups are attached to the surface via the Diels-Alder cycloaddition of a diene. The cycloaddition of cyclopentadiene or [(trimethylsilyl)methyl]cydopentadiene to the cyclic imide-functionalized plasma polymer is shown in Scheme 1.17. In this case, the extent to which maleic anhydride groups are converted is controllable, such that the number density of functionalized groups can be tailored to comply with the adhesion between different types of solid surface. 

Supemucleophilic polymers containing the 4-(pyrro-lidino)pyridine group were synthesized from the corresponding maleic anhydride copolymers and also by cyclopolymerization of N-4-pyridyl bis(methacryl-imide). The resulting polymers were examined for their kinetics of quaternization with benzyl chloride and hydrolysis of pj-nitrophenylacetate. In both instances, the polymer bound 4-(dialkylamino)pyridine was found to be a superior catalyst than the corresponding low molecular weight analog. 

Maleic acid imides (maleimides) are derivatives of the reaction of maleic anhydride and ammonia or primary amine compounds. The double bond of a maleimide may undergo an alkylation reaction with a sulfhydryl group to form a stable thioether bond (Chapter 2, Section 2.2). Maleic anhydride may presumably undergo the same reaction with cysteine residues and other sulfhydryl compounds. 

Crosslinking of amine- or hydroxy-terminated PAMAM dendrimers using cyclic anhydride - amine or cyclic anhydride - hydroxy addition reactions was employed for preparation of crosslinked thin films of very low permeability [73], Polyanhydrides, such as maleic anhydride-methyl vinyl ether copolymers, were used as crosslinking components. In the case of amine-terminated PAMAM, crosslinking and chemical stability were further increased by imidization of the maleamic acid groups retro-Michael eliminations were followed by Michael additions to further crosslink the film. 

The monomer 91 was prepared in a multistep process and the authors did not quote the yield obtained for the final product (Fig. 41). In the first step the dianhydride 87, was reacted with m-nitroaniline 88 to form the mono imide anhydride 89 without any of the bis imide product being reported. Once this material was isolated the remaining anhydride functionality was reacted with 4-aminobenzocyclobutene 60 to form the JV-benzocyclobutenyl imide, 90. The nitro group was reduced to the amine (H2,10% Pd/C) which in turn was reacted with maleic anhydride to afford the final AB monomer, 91. Polymerization of 91 was carried out in a DSC (10 °C/min to 450 °C) [14]. Monomer 91 had a melting point of 99 °C and the final homopolymer had a Tg of257 °C [14]. A TGA of the homopolymer indicated that at 508 °C the polymer suffered a 10% weight loss. 

Monomers 111 (a -d), were prepared from the common starting material 15 by a potassium phenate displacement of the aromatic nitro group. The yields of the keto-ether amine products ranged from 90 to 100% and were of sufficient purity after extractive work up to be utilized directly in the synthesis of the various maleimide monomers. Imidization of the aminobenzocyclobutenes was accomplished using standard reaction conditions (maleic anhydride to form the amic acid followed by cyclodehydration with acetic anhydride and triethyla-mine) and provided the maleimide products in yields ranging from 60 to 90%. 

The sulfenyl phthalimides are one of the oldest groups of fungicides and are effective, safe and persistent (B-77MI10706). Captan (59) is cheaply made from the Diels-Alder adduct of butadiene and maleic anhydride, followed by conversion to the imide and reaction with trichloromethanesulfenyl chloride. Folpet (60) and captafol (61) are similar in structure. 

A15.1.1.9 Imides. Compounds that have two acyl groups bonded to a single nitrogen are known as imides (R—CO—NH—CO—R ). The most common imides are cyclic ones (maleimide). Maleimide will convert to maleic acid under water and acid/base. Another example of imide hydrolysis is pheno-barbital in which phenobarbital (a cyclic imide) is hydrolyzed to form urea and a-ethylbenzeneacetic acid. 

A sequence of bromination of a 3-indolyl acyl group followed by azide displacement and reduction, provides an effective route to 3-(a-aminoacyl)indoles <88JHC469>. Indoles react readily with oxalyl chloride at C-3 and the products have been used in combination with aryl acetic acid derivatives to generate indolyl-substituted maleic anhydrides and imides, as precursors for indolocarbazole antibiotics <90TL2353,93TL5623>. 

Since the mono-azo intermediates and 3,3 -DCB all contain reactive amine functionalities, decomposition products could be trapped using chemically reactive polyolefin resins added to the color concentrate formulation. In principle, commercially available maleic anhydride-modified polyethylene resins and waxes possess the necessary functionality to react with amine compounds as they are produced. Potentially harmful 3,3 -DCB decomposition products would then be immobilized as pendant groups on the polymer backbone in the form of imide or amide/carboxylic acid pairs (Figure IB). 

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