Maleimide phenylmaleimide

Nitrones derived from cyclic acetals of D-erythrose (479) and (689) and of D-threose (480) and (690), reacted with N -phenylmaleimide D15a to afford the corresponding diastereomeric isoxazolidines (691-706) (Scheme 2.295). The stereoselectivity is dependent on the substituents in the nitrone. In the case of nitrones (479) and (689) the cycloaddition is exo-selective. It was observed that microwave irradiation decreased the reaction times of the cycloadditions dramatically. For example, for nitrone (689) and dipolarophile D15a the reaction time decreased from 11 h to 8 min and for nitrone (690) and D15a it decreased from 3 h to 10 min. Moreover, microwave irradiation reversed the ratio of erythro-frans/erythro-r/.v adducts from 63 37 to 39 55, see compound (689). Cycloadditions of the chiral maleimides D15b and D15c are less stereoselective (817). 

C, A-diphenyl nitrones (p-XC6H4CHN(0)Ph, X = NO2, Cl, H, Me and MeO) with N-phenylmaleimide to form 2,3,6-triaryl derivatives of l-oxa-2,6-diazabicyclo[3.3.0]octane-5,7-dione. No enthalpy of formation data are available for A-phenylmaleimide or for maleimide itself. However, it is available for the corresponding A-methyhnaleimide along with some other imides. The gas phase enthalpy of hydrogenation of this species (derived as the difference between its enthalpy of formation and that of N-methylsucc-inimide ) is 133.7 2.2 kJmoC. This value is essentially the same as for ethylene (derived as the difference between its enthalpy of formation and that of ethane) of 136.3 0.4 kJmoH. Therefore, let us assume the reaction of the above parent nitrone with ethylene to form the diphenylated isoxazolidine, shown in equation 12, has very much the same exothermicity as with A-phenylmaleimide, namely ca 82 kJmol . If so, the enthalpy of formation of 2,3-diphenylisoxazolidine would be 233 kJmol . Now, is this value plausible ... 

The procedure described here is based on a method outlined in U. S. patent 2,444,536.2 N-Phenylmaleimide has also been prepared by the dry distillation of the aniline salt of malic acid, 4 by treating the aniline salt of malic acid with phosphorus pent-oxide,5 and by treating maleanilic acid with phosphorus trichloride or with phosphorus pentoxide.5 Ring-substituted N-phenylmaleimides, viz., N-(/>-methoxyphenyl)-, N-(p-ethoxy-phenyl)-, and N-(/>-nitrophenyl)maleimide, have been prepared by treatment of the appropriate maleanilic acids with acetic anhydride and fused potassium acetate.7... 

Substituted 2-vinylindoles yield the di- and tetra-hydrocarbazoles with JV-methyl-maleimide and maleic anhydride, and with DMAD, respectively (81UP30500, 82CJC419) and the expected cycloadducts are obtained from the reaction of 4-(2-indolyl)-l,2,5,6-tetrahy-dropyridines with iV-phenylmaleimide and with acrylonitrile (68HCA264). Both l-(l-methyl-... 

N-Phenylmaleimide Maleimide, N-phenyl- 1H-Pyrrole-2,5-dione, 1-phenyl- (941-69-5), 67, 133... 

The most commonly used commercial monomers that increase the Tg of ABS are maleimides (most recent commercial addition), maleic anhydrides (MA), and substituted styrenes. The majority of ABS produced in North America and Europe relies on a-methylstyrene (aMeS) or /V-phenylmaleimide (PMI) as... 

The generation of the carbcxi-carbon double bond of unsaturated nitrogen heterocycles by the rDA reaction of cycloadducts that act as protected ethylenes has been accomplished. Azetines have been prepared by this method. Another example is the synthesis of l-methyl-3-pyrroline (201). By protecting the ethylene of N-methylmaleimide (199) with furan and then reducing with lithium aluminum hydride, adduct (200) was obtained (equation 86). Pyrolysis of adduct (200) at 250-300 C gave l-methyl-3-pyrroline (201) in 60% isolated yield. The ethylene moiety of N-substituted maleimides can also be generated via rDA reactions. Examples include the generation of N-phenylmaleimide (equation 87) and of N-acetoxymaleimide (equation 88). ... 

Padwa and coworkers found that a-cyanoaminosilane 12a is a convenient synthon for azomethine ylide 15 which is extensively used in heterocyclic synthesis [7]. AgP has been adopted to generate the ylide 15 from 12a for the preparation of pyrrolidine derivative 14 (Sch. 4). Various dipolarophiles including A-phenylmaleimide (13) can be used for the cycloaddition. When iV-[(trimethylsilyl)methyl]-substituted indole 16 is reacted with AgP in the presence of maleimide 13, pyrrolo[l,2-a]indole 17 is formed in good yield, retaining the CN group [8]. A silver-bonded carbonium ion is assumed to be a reactive intermediate. Reaction of a cyano-substituted azomethine ylide, derived from (silylmethylamino)malononitrile 12b and AgP, with methyl propiolate (18) provides 3-carbomethoxy-A-benzylpyrrole (19) [9]. Epibatidine, a novel alkaloid, was successfully synthesized by employing the [3 + 2] cycloaddition of azomethine ylide with electron-deficient alkenes as a key step [10]. 

Vinylimidazoles participate in Diels-Alder reactions with a wide variety of dienophiles <2006SL965>. Thus, cycloadduct 508 is obtained at room temperature on reaction of compound 506 with A -phenylmaleimide 507 in 91% yield. A similar reaction occurs between natural product oroidin 509 and maleimide 510 to give cycloadduct 512 with catalysis by Y(OTf)3 511 (Scheme 116) <20060L819>. 

Decarboxylative condensation of N-unsubstituted tx-amino acids with benzaldehyde as an aromatic aldehyde requires somewhat harsher conditions. Benzaldehyde and oc-amino acids are heated under reflux in DMF together with N-phenylmaleimide. The azomethine ylides 108 generated can be captured as mixtures of several stereoisomeric cycloadducts (84CC180). 1-Aminocyclopentane-l-carboxylic acid undergoes a similar reaction with pyridine-3-carbaldehyde in the presence of N-phenylmaleimide to afford a spirocyclic cycloadduct, the maleimide cycloadduct of azomethine ylide 109 (84CC182). 

Because of the results found with p-(chloromercuri)benzoate and because /3-galactosidase is believed to be a sulfhydryl enzyme, it seemed advisable to investigate the effects of other sulfhydryl reagents. Virtually no inhibition of /3-galactosidase was found in the presence of iodoacetam-ide (9 X 10 M) over a period of 7 hours. A -Phenylmaleimide, at concentrations as high as 8.7 X 10 M, produced less than 10 % inhibition over a 20-hour period. However, when the concentration of V-phenyl-maleimide was raised to 9.1 X 10 M, assay of the incubation mixture revealed that 50% inhibition of /3-galactosidase occurred within a 2-hour period when the experiment was performed in 2-amino-2-(hydroxymethyl)-1,3-propanediol— acetic acid buffer, pH 8.0. Virtually no activity was lost when the latter experiment was repeated in phosphate buffer (Na salts) at the same pH. 

DiallyIphthalate, which has been converted under radical conditions to a low polymer, photocrosslinks in the presence of N-phenylmaleimide and Michler s ketone sensitizer (.2 ). Possibly the cross I inking involves copolymerization of unreacted ally I groups with the maleimide. 

Dienopyranosides 27. 33, 36 and 42 are less selective than diene 15 and add to maleimide (28) to give mixtures of cycloadducts with d.r. s of 80 20, 82 18 and 75 25, respectively. Diene 33 gives cycloadducts with iV-phenylmaleimide in a d.r. 86 14. The best results are achieved for dienes 27 (maleimide as dienophile) and 42 (iV-phenylmaleimide as dienophile) which both give single adducts 29 and 43, respectively19. 

---