Maleic anhydride substituted

Dimethyl-1,3-diphenyl Maleic anhydride, substituted olelins, bicyclic compounds 86, 104, 174, 314,315... 

Dimethyl-1,3-di-p-tolyl Maleic anhydride, substituted maleimides 100, 175... 

A dispute about the configuration of the substance formed from maleic anhydride and ketals (12) in ether at 0 C has been terminated by evidence that the products are mixtures.33 A more general study indicates that, with maleic anhydride, substituted furans almost always supply in the first stage a 1 1 adduct apparently formed by way of a charge-transfer complex.33 Detailed structural studies have established that the substituents may exert steric effects able to influence individual rates of formation the resulting endo-exo ratios have been determined.34 Rate studies with para-substituted... 

The polyispbptylenes (PIB) having molecular weights ranging from 1000 to 2000 are substituted by maleic anhydride, and the polyisobutylene succinic anhydride (PIBSA) formed is neutralized by a polyethylene-polyamine as indicated in Figure 9.10. 

Like butadiene, allene undergoes dimerization and addition of nucleophiles to give 1-substituted 3-methyl-2-methylene-3-butenyl compounds. Dimerization-hydration of allene is catalyzed by Pd(0) in the presence of CO2 to give 3-methyl-2-methylene-3-buten-l-ol (1). An addition reaction with. MleOH proceeds without CO2 to give 2-methyl-4-methoxy-3-inethylene-1-butene (2)[1]. Similarly, piperidine reacts with allene to give the dimeric amine 3, and the reaction of malonate affords 4 in good yields. Pd(0) coordinated by maleic anhydride (MA) IS used as a catalyst[2]. 

Maleic anhydride condenses with 2-aminothiazole-4-carboxylic acid giving the raaleimide 107 (269) another report claims, however, that the reaction of 2-amino-4-methylthiazole with this anhydride gives the N-substituted maleamic acid (108) (Scheme 73) (270). 

V- Alkylpyrroles react with maleic anhydride to give the electrophilic substitution product (7) and not the Diels-Alder addition product found for... 

Endo adducts are usually favored by iateractions between the double bonds of the diene and the carbonyl groups of the dienophile. As was mentioned ia the section on alkylation, the reaction of pyrrole compounds and maleic anhydride results ia a substitution at the 2-position of the pyrrole ring (34,44). Thiophene [110-02-1] forms a cycloaddition adduct with maleic anhydride but only under severe pressures and around 100°C (45). Addition of electron-withdrawiag substituents about the double bond of maleic anhydride increases rates of cycloaddition. Both a-(carbomethoxy)maleic anhydride [69327-00-0] and a-(phenylsulfonyl) maleic anhydride [120789-76-6] react with 1,3-dienes, styrenes, and vinyl ethers much faster than tetracyanoethylene [670-54-2] (46). 

Process Technology Evolution. Maleic anhydride was first commercially produced in the early 1930s by the vapor-phase oxidation of benzene [71-43-2]. The use of benzene as a feedstock for the production of maleic anhydride was dominant in the world market well into the 1980s. Several processes have been used for the production of maleic anhydride from benzene with the most common one from Scientific Design. Small amounts of maleic acid are produced as a by-product in production of phthaHc anhydride [85-44-9]. This can be converted to either maleic anhydride or fumaric acid. Benzene, although easily oxidized to maleic anhydride with high selectivity, is an inherently inefficient feedstock since two excess carbon atoms are present in the raw material. Various compounds have been evaluated as raw material substitutes for benzene in production of maleic anhydride. Fixed- and fluid-bed processes for production of maleic anhydride from the butenes present in mixed streams have been practiced commercially. None of these... 

Poly(phenylene oxide)s undergo many substitution reactions (25). Reactions involving the aromatic rings and the methyl groups of DMPPO include bromination (26), displacement of the resultant bromine with phosphoms or amines (27), lithiation (28), and maleic anhydride grafting (29). Additional reactions at the open 3-position on the ring include nitration, alkylation (30), and amidation with isocyanates (31). 

The most useful syntheses of pyridazines and their alkyl and other derivatives begins with the reaction between maleic anhydride and hydrazine to give maleic hydrazide. This is further transformed into 3,6-dichloropyridazine which is amenable to nucleophilic substitution of one or both halogen atoms alternatively, the halogen(s) can be replaced by hydrogen as shown in Scheme 110. In this manner a great number of pyridazine derivatives are prepared. 

Over the years many attempts have been made to produce commercial acrylic polymers with a higher softening point than PMMA. The usual approach was to copolymerise MMA with a second monomer such as maleic anhydride or an N-substituted maleimide which gave homopolymers with a higher Tg than PMMA. In this way copolymers with Vicat softening points as high as 135°C could be obtained. 

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 ]. 

Benz[/]isoindole (125), recently prepared from the p-toluene-sulfonyl derivative (124), proved to be too unstable for isolation, but eould be trapped in solution as the Diels-Alder adduct (127). The corresponding 1-phenyl derivative (126) was also prepared and, aecording to spectral measurements, reacts with maleic anhydride to give the product (128) derived by additive substitution. This subsequently rearranged to the adduct (129). The same behavior is observed in the reaction of (126) with V-phenylmaleimide. This provides the first clear indication that substitution products from isoindole derivatives and dienophiles can be converted into the normal addition products. 

The equilibrium between oxepin and benzene oxide created interest in performing Diels-Alder reactions trapping one or both isomeric structures.1 The reaction of maleic anhydride or maleic imide with oxepin and substituted derivatives gives products 1 derived from the addition of the dienophile to the benzene oxide structure.2-l4-126 14 9 156 158 228 231-259... 

All attempts to prepare other [2 + 4] cycloadducts of sulfoxides 115 with dienophiles such as maleic anhydride, ethyl azodicarboxylate, etc., have failed60. A method for preparing ordinary alkyl-substituted thiirene oxides (e.g. 18 R1 = R2 = alkyl) is still lacking. 

Thiophene 1,1-dioxide (61) is too unstable to isolate and dimerizes with loss of S02 to give 3a, 7a-dihydrobenzothiophene 1,1-dioxide (172) in 34%113. However, alkyl-substituted thiophene 1,1-dioxides can serve as dienes in the Diels-Alder reaction, since the aromatic properties of the thiophene nucleus are lost completely and the n-electrons of the sulfur atom are used for forming the bond with oxygen. The sulfones 173-178 are found to react with two moles of maleic anhydride at elevated temperature to give bicyclic anhydrides114. Thus, at high reaction temperature, S02 is split off to give cyclohexadiene... 

As previously discussed, solvents that dissolve cellulose by derivatization may be employed for further functionahzation, e.g., esterification. Thus, cellulose has been dissolved in paraformaldehyde/DMSO and esterified, e.g., by acetic, butyric, and phthalic anhydride, as well as by unsaturated methacrylic and maleic anhydride, in the presence of pyridine, or an acetate catalyst. DS values from 0.2 to 2.0 were obtained, being higher, 2.5 for cellulose acetate. H and NMR spectroscopy have indicated that the hydroxyl group of the methy-lol chains are preferably esterified with the anhydrides. Treatment of celliflose with this solvent system, at 90 °C, with methylene diacetate or ethylene diacetate, in the presence of potassium acetate, led to cellulose acetate with a DS of 1.5. Interestingly, the reaction with acetyl chloride or activated acid is less convenient DMAc or DMF can be substituted for DMSO [215-219]. In another set of experiments, polymer with high o -celliflose content was esterified with trimethylacetic anhydride, 1,2,4-benzenetricarboylic anhydride, trimellitic anhydride, phthalic anhydride, and a pyridine catalyst. The esters were isolated after 8h of reaction at 80-100°C, or Ih at room temperature (trimellitic anhydride). These are versatile compounds with interesting elastomeric and thermoplastic properties, and can be cast as films and membranes [220]. 

Fallis and coworkers studied Jt-facial selectivity in the reactions of series of 5-substituted 1,2,3,4,5-pentamethylcyclopentadienes Cp -X. They reported that the diene 5 (Cp -X X = SCH3) with maleic anhydride proceeded more slowly than that of the 5-oxygen substituted cyclopentadienes 6 and 7 (Cp -X X = OH, OCH3), where the HOMO of the diene 5 lies higher than those of 6 and 7 [7, 8] (Table 2). These results seemed to suggest that in the case of the reaction of 5 the NHOMO considerably contributed to the reactions. 

Several other complexes, M(CNBu )jL (L = an activated olefin), have also been reported recently (110). This group of complexes, with the ligands (L) including maleic anhydride, fumaronitrile, and tetracyano-ethylene, arises from isocyanide ligand substitution by the olefin. Less active olefins such as ethylene and diphenylacetylene, and azobenzene did not react. 

Diels-Alder cycloadditions are sensitive to steric effects of two major types in the diene. Bulky substituents on the termini of the diene hinder approach of the two components to each other and decrease the rate of reaction. This effect can be seen in the relative reactivity of 1-substituted butadienes toward maleic anhydride.19... 

Photocycloadditions of maleic anhydride and dimethylmaleic anhydride to various other substituted cyclohexadienes and to cycloheptatriene have also been reported/58,97 98 ... 

These reactions are found to be promoted by electron-donating substituents in the diene, and by electron-withdrawing substituents in the alkene, the dienophile. Reactions are normally poor with simple, unsubstituted alkenes thus butadiene (63) reacts with ethene only at 200° under pressure, and even then to the extent of but 18 %, compared with 100% yield with maleic anhydride (79) in benzene at 15°. Other common dienophiles include cyclohexadiene-l,4-dione (p-benzoquinone, 83), propenal (acrolein, 84), tetracyanoethene (85), benzyne (86, cf. p. 175), and also suitably substituted alkynes, e.g. diethyl butyne-l,4-dioate ( acetylenedicarboxylic ester , 87) ... 

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