Maleic acid imides, reaction with

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. 

MDA reacts with acid anhydrides to form amides. In the reaction with maleic anhydride both of the amino hydrogens are replaced to form the imide, A[,Ar-(methylenedi-/)-phenylene) dimaleimide [1367-54-5]... 

The partially hydrogenated phenanthrene derivative 18 (entry 4) is a very moderate diene due to the steric crowding caused by the substituents and the anulated rings, and it reacts even with highly reactive dienophiles such as maleic anhydride (MA) or N-phenylmaleic imide only at high pressure. The minor product 20 in the reaction with MA obviously stems from diene 21. This can be explained by a double-bond isomerization 18 - 21 prior to the cycloaddition, certainly catalyzed by traces of acid present in the MA. In the absence of acid only the Diels-Alder adduct 22 derived from diene 18 was observed. In the reaction of diene 23 with MA (entry 5) a similar sequence of steps was observed. A [1,5] shift of the C—O bond in 23, again certainly acid-catalyzed, produces the diene 26 followed by the Diels-Alder reaction with MA to give 24 and 25. 

An interesting approach to maleimide-terminated phenoxy resin has recently has described (42). para-Maleimidobenzoic acid was reacted with diglyci-dylbisphenol-A epoxy resin in the presence of catalyst to provide the bismale-imide of Fig. 13. Instead of diglycidyl bisphenol-A, linear epoxy resin pre-polymers can be used in this reaction to form a maleimide terminated phenoxy resin. Another suitable functionalized monomaleimide is m- or p- N-(hydroxyphenyl) maleimide which is synthesized from maleic anhydride and m-aminophenol in DMF as a solvent at 70 °C. The purified hydroxyphenyl maleimide was reacted with epoxy resin to form novel BMIs as outlined in Fig. 14. The new BMI and phenoxy oligomers polymerize at temperatures of 200-220 °C, but the cure temperatures can be significantly lowered when catalysts such as imidazoles or triphenylphosphine are added. The cured homopolymers show Tg of 140 and 230 °C for the n = 2 and the n = 1 polymer, respectively(43). 

R) - and (S)-l-phenylethylamine to the diethyl esters of fumaric and maleic acid which are carried out by heating the pure compounds, without solvent, to 115-120 °C for three days (see Table 1). The reaction mixtures are then hydrolyzed and hydrogenated to give aspartic acids in high yields (85-87%) but very low optical purities (6.3-12.2%). A number of intermediates and by-products arc isolated, especially amides and imides of the dicarboxylic acids participating in the reaction. This may explain the low overall diastereoselectivity which can be calculated from the low optical rotation of the isolated aspartic acids. However, any discussion of the reaction mechanism remains difficult because the structures of the substrates and products of the actual addition step itself are not known with certainty. It is known that... 

The sulfosuccinimdes may be of two varieties, one analogous to the previously mentioned succinic acid derivatives, where the sulfonate group is added across the double bond of maleic acid and subsequently reacted to produce the cyclic imide. The second variety requires a different synthetic approach, since the locations of their hydrophilic and hydrophobic groups are reversed from those of the succinic acid derivatives. In this case, the starting material is a 2-alkyl, alkenyl, or similar succinic anhydride, which is reacted with the appropriate sulfoalkylamine to produce the amide acid, followed by dehydration to the imide. Similar reaction schemes can be used to prepare di- and higher polyesters and amides of malonic acid, itaconic acid, and other polycarboxylic acids. 

The reactions of primary amines and maleic anhydride yield amic acids that can be dehydrated to imides, polyimides (qv), or isoimides depending on the reaction conditions (35—37). However, these products require multistep processes. Pathways with favorable economics are difficult to achieve. Amines and pyridines decompose maleic anhydride, often ia a violent reaction. Carbon dioxide [124-38-9] is a typical end product for this exothermic reaction (38). 

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%. 

Diels-Alder reactions of 341 with maleic anhydride and A-phenylmale-imide and of 344 with maleic anhydride occur quite easily at 20°C on dehydration with acetic acid the aromatized products are obtained in high yields. ... 

Other preparations of 2-iminothiazolidin-4-ones which are discussed in the review by Brown139 utilize the reactions of thiourea with a-hydroxy acids,146 ethyl diazoacetate,73 glycidic esters,74,147 cinnamic acid,148 unsaturated diacids (fumaric, maleic, and citraconic) or their esters or imides,149-152 and propiolic esters.153,154 There has been considerable controversy in the literature surrounding the propiolic ester synthesis since many workers have proposed that the products are 1,3-thiazines (see Section IV, B, 1). The pertinent papers in this controversy have been summarized by Cain and Warrener.155 Nagase158 has recently settled the argument in favor of the 2-iminothiazolidin-4-... 

Bradshaw [74] reported in 1966 that maleimide undergoes sensitized photochemical addition to benzene, producing the imide analog of the corresponding maleic anhydride photoadduct. The author observed that the reaction probably proceeds by the addition of electronically excited maleimide to benzene. The photoaddition proved successful also with toluene, /-butylbenzene, and ethylbenzene. Simultaneously, Bryce-Smith and Hems [75] reported that 2 1 photoadducts are formed from maleimide, iV-n-butyl-,. V-benzyl-, iV-o-tolyl-, and iV-2,6-xylylmaleimide with benzene.. V-Phenyl, N-p-tolyl-, and A-p-methoxyphenylmaleimide did not form photoadducts. Trifluoroacetic acid was found to be virtually without effect on the photoaddition of N-n - bulyI maleimide No phenyl-A- -butylsuccinimide was detected [36], It was concluded that a dipolar intermediate is not involved. When N-n-bulylmalcimide and benzene were irradiated in the presence of tetra-cyanoethylene, a 1 1 1 adduct was formed [37],... 

Azo compounds like esters or imides of azo dicarboxylic acid act as reactive dienophiles in normal electron demand hetero Diels-Alder reactions due to the strong activation caused by two electron-withdrawing moieties. In the last years, considerable attention has focused on alkyl and phenyl derivatives of 1,2,4-tria-zoline-3,5-diones since their cycloadditions to chiral dienes proceed with often excellent facial selectivities. Thus, when reacting an oxapropellane derived diene with N -methyltriazolinedione, Paquette et al. obtained the cycloadduct as single diastereomer, but both maleic anhydride and N-phenyl maleimide were distinctly less reactive and turned out to undergo cycloadditions with poor selectivities [289]. 

Mika and Tanaka also suggested that if reaction (10) occurs, then the retardation effect caused by maleic and phthalic acids, ketones and esters may be attributed to formation of imides, ketimines and amides. The inhibition caused by dioxane, tetrahydrofuran and diisopropyl ethers may be attributed to the fact that the (R2NH HX) reacts with ethers to yield a complex, thereby preventing the epoxides from reacting. This would be expected because the four, five and six member rings are better hydrogen donors than three component epoxy rings. 

Unsaturated poly(ester-imide) resins are known having imide structures at the end of the molecule or in the backbone. Chain termination by imide is frequently done with the tetrahydrophthalic anhydride (23) aminoethanol (9) reaction product [10,201-204]. In the synthesis of these resins, maleic anhydride is used. It is cheap and a world-wide available raw material, having the advantage of generating per mol only one mol of distillate. Patents are known where fumar-ic acid is claimed, e.g., in [205], but it is probably not frequently used in industrial processes. Anyway, under the conditions of the esterification reaction, a part of the maleate is isomerised into the fumarate [206]. To get materials with good heat resistance the use of THEIC is claimed for branching the unsaturated poly(ester-imide) resins [202]. Flexibility and heat resistance are improved when fatty acids, e.g., castor oil fatty acid [205,207], are build into the macromolecule. 

Typically, bismaleimides are synthesized by reacting a diamine with maleic anhydride in two steps [277,278]. In the first one a bismaleamic acid is formed in a fast, exothermic reaction, that is carried out at room temperature. The second step consist of the imidization of the maleamic acid, usually by chemical means, with acetic anhydride in the presence of a small amount of basic sodium acetate. This step is carried out at moderate temperature to avoid premature polymerization of the double bonds. The use or tertiary amines as catalyst is also possible but the obtained product is less pure than in the case of sodium acetate. In fact, this effect has been used to prepare bismaleimides with a lower melting point, and consequently with a wider processing window [279]. 

The important tetramethrin alcohol 323 (Reaction scheme 236) is simply made from butadiene and maleic anhydride, and then rearranged to the conjugated dicarboxyhc acid 324, selectively catalyzed by carbonyls of transition metals Uke Pd, Rh and ruthenium. Imidation with urea and hydroxymethylation produces the final product 323 [688, 689]. 

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