Maleimides 2-imino

Reaction of 3-amino-4-imino-47/-pyrido[l,2- ]pyrazines 319 with DMAD and maleimides 321 yielded 2,2 -bipyr-idine-3,4-dicarboxylates 320, and mixtures of bi- and tricyclic derivatives 322 and 323, respectively (Scheme 27) <1996JPR430>. In the cases of maleimide reactions, higher temperature (at 160°C in xylene) in an autoclave gave only 323. When pyrido[l,2- ]pyrazine 319 (Ar = 4-MeC6H4) was reacted with W-(4-methylphenyl)-maleimide 321 (R = 4-MeC6H4), 324 could be isolated. 

The reaction of 5(4H)-oxazolones (32) and miinchnones with triphenylvinylphos-phonium bromide (33) provides a mild synthesis of substituted pyrroles (34) (Scheme 11). The cycloaddition-elimination reactions of 5-imino-l,2,4-thiadiazolidin-3-ones with enamines and ester enolates produce 2-iminothiazolidines. " Chiral isomtinchnone dipoles show jr-facial diastereoselectivity with IV-phenyl- or A -methyl-maleimide in refluxing benzene. ... 

Imino-3-oxolen-5-ones (isomaleimides) (52) can be polymerized and copolymerized to produce polymers with ring structures which are isomeric with those of the poly(maleimides) (7). In contrast to their maleimide isomers (6), isomaleimides (52) displayed reactivities when copolymerized with styrene that were dominated by the resonance effects of the substituent R (77MI11103). 

A new methodology for the preparation of phenyliminothiazolidinones has been described. The reaction of maleic anhydride (61) with the thiourea 62 gave the 2-imino-l,3-thiazolidin-4-one 63. If maleimides are treated under similar conditions. 

Imino-4-thiazolidon-5-acetamides from maleimides and thioureas... 

Resin-bound maleimide has been used as a dipolarophile in the synthesis of N-substituted pyrrolidines as well (Scheme 11.2). " Cycloaddition with a-imino esters, which were generated from aryl aldehydes and amino acid esters, yielded resin-bound pyrrolidines. The compounds were bound to the acid-cleavable SASRIN resin with an ester linkage and then cleaved from the resin as carboxylic acids with highly diluted trifluoroacetic acid. 

Thermal stability measurements have been carried out on numerous other polymers including polyethylene ethylene vinyl-alcohol copolymer [12], polyaniline [13], ) 3 s-stilbene-N-substituted maleimides [14], cellulose [15-20], polystyrene [14, 16], ethylene-styrene copolymers [21,22], ST-DVB-based ion exchangers [23], vinyl chloride-acrylonitrile copolymers [24], polyethylene terephthalate [25], polyesters such as polyisopropylene carboxylate [26], polyglycollate [27-29], Nylon 6 [30], polypyromellitimides, poly-N-a-naphthylmaleimides [26,31], polybenzo-bis(amino-imino pyrolenes) [32], polyvinyl chloride [33-35], acrylamide-acrylate copolymers and polyacrylic anhydride [36-38], polyamides [39], amine-based polybenzo-oxazines [40], polyester hydrazides [41], poly-a-methyl styrene tricarbonyl chromimn [42], polytetrahydrofuran [43], polyhexylisocyanate [44], polyurethanes [45], ethylene-... 

Rhodium(I)-catalyzed [2 + 2 - - 2] cycloaddition of A(-propargyl maleimide and a 1,6-diyne followed by silver(I) acetate-mediated 1,3-dipolar cycloaddition with imino esters afforded endo cycloadducts in good yields (Scheme 4.39) [43]. 

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