Ethyl-methyl-maleimide

Further breakdown to mono-pyrrolic oxygenation products as further remains of Chls have also been considered (3, 102). These studies received further support from recent work by Shioi and coworkers, who obtained evidence for the presence of hematinic acid (4-methyl-2,5-dioxo-2,5-dihydropynole-3-propionic acid), ethyl-methyl-maleimide and a putative bicyclic degradation product of the ring-C-E section of Pheo a (103). 

O-Methylisourea hydrogen sulphate (2-methylpseudourea sulphate) [29427-58-5] M 172.2, m 114-118 , 119 . Recrystd from MeOH-Et2O (327g of salt dissolved in IL of MeOH and 2.5L of Et20 is added) [Fearing and Fox JACS 16 4382 1954 ]. The picrate has m 192° [Odo et al. JOC 23 1319 1958]. iV-Methyl maleimide [930-88-1] M 111.1, m 94-96 . Crystd three times from ethyl ether. 

A-Methyl maleimide [930-88-1] M 111.1, m 94-96°. Crystd three times from ethyl ether. 

In 2012, Keglevich and coworkers reported the catalyst-free synthesis of a series of new >P(0)-substituted maleic derivatives (62) via microwave-assisted phospha-Michael addition of diall l phosphites, ethyl phenyl-H-phosphinate, and diphenylphosphine oxide to Al-phenyl and N-methyl maleimide (61), in most of the cases without any solvent, in good yields (71-98%) and within 3 h (Scheme 29). This method is advantageous over the previously reported method of Jiang et al. in terms of using no solvent or catalyst. 

A microsomal O -methyltransI erase that methylates a number of alkyl-, methoxy-, and halophenols has been described from rabbit liver and lungs. These methylations are inhibited by SKF-525, A-ethyl-maleimide and /->-chloromercuribenzoate. A hydroxyin-dole O-methyItransferase, which methylates A -acetyl-serotonin to melatonin and, to a lesser extent, other 5-hydroxyindoles and 5,6-dihydroxyindoles, has been described from the pineal gland of mammals, birds, reptiles, amphibians, and fish. 

A further example of the use of 2//-thiopyrans as surrogates for m-substituted dienes involves the use of the protected 3,4-dihydio-3-(3-oxobutyl)A//-thiopyranA-onc, 3-[2-(2-methyl-l,3-dioxolan-2-yl)ethyl]-4-[tris(l-methy-lethyl)silyl)oxy-2//-thiopyran 328 as an equivalent of l-ethenyl-2-methylcyclohexene in Diels-Alder reactions. The thiopyran reacted with various maleimides to yield the endo cycloadducts and with methyl propenoate to give the exo adduct under either thermal or Lewis-acid-catalyzed conditions. In the latter case concomitant release of the protected ketone functions occurs, acid-catalyzed cyclization of which generates a fused cyclohexenone ring (Scheme 67). Desulfurization, preferably before the aldol cyclization, leads to derivatives of 2,3,4,4a,5,6,7,8-octahy-dro-4a-methylnaphthalenes < 1997CJC681 >. 

More or less similar behavior has been observed (8) in the blends of the copolymer or the terpolymer with the following bis-A polycarbonate, polyvinyl chloride, poly (ethyl methacrylate), and a terpolymer made from methyl methacrylate, N,N -dimethyl acrylamide, and N-phenyl-maleimide. Because of this unique miscibility characteristic of the a-methyl styrene interpolymers, an attempt was made at compati-bilizing polyarylethers with the interpolymers by attaching pendant chemical groups known to exist in systems with which the interpolymers are miscible. 

Inhib. abbrev. DTT = dithioghreitol E64D = epoxysuccinyl-L-leucyl-amido-3-methyl-butane ethyl ester EDTA = ethylene-diamine-tetra-acetic acid EGTA = ethylen-glycol-tetra-acetic acid LHVS = morpholinurea-leucine-homophenyl-alanine-vinylsulfone-phenyl NEM = N-ethyl-maleimide PAI = plasminogen activator inhib. PMSF = phenil-methyl-sulfonil fluoride SBTl = soybean trypsin inhib. TIMP = tissue inhib. of metalloproteinases TPCK = tosyl-L-phenyl-alanyl-chloro-methane Al.so termed stephins. 

From the reactions of l,3-dithiolylium-4-olates, for example, (115), with alkenes like A(-phenyl maleimide, acrylonitrile, ethyl acrylate, azirines, a-methyl-styrene, methyl cinnamate, tetra-cyanoethylene, or 2,3-dimethylbut-2-ene, the stable 1 1 adducts, such as (116), are obtained (Equation (15)) <76JOC1724, 78CB3029, 79HCA1236, 79LA360>. 

Fig. 2. Accumulation of medicarpin in Ladino clover callus elicited with N-ethyl maleimide. Data are from three separate experiments. 1) Callus was prepared as described (19) and divided into vials containing the indicated concentrations of NEM (one vial for each NEM concentration). After 24-hour incubation period, callus was extracted with methyl ethyl ketone, and medicarpin concentrations determined in the extracts by HPLC (19) - . 2) Same as experiment 1,...

Some polymerization systems progress without initiators of polymerization. Those systems are not influenced by oxygen. A combination of bis-maleimide (bis[l-(2-ethyl-4,6-dimethylphenyl)pyrrolidine-2,5-dion]) and vinylether (l,4-bis[(ethenyloxy)methyl]cyclohexane) is polymerized under high reaction speed without an initiator. Those molecules are shown in Figure 1.6. No inhibition by oxygen is found in this polymerization system. 

A somewhat different alkylation (arylation) mechanism involves the reactions of GSH with unsaturated compounds like divinylsulfone, fV-ethyl-maleimide (51a, b), and several quinones. The adducts with 1,4-naphthoquinone and also 2-methyl—1,4-naphthoquinone have been prepared (52). 

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