Michael additions poly

Poly(vinyl alcohol) undergoes Michaels addition with compounds containing activated double bonds, including acrylonitrile (145—150), acrylamide (151—153), A/-methylolacrylamide (154—156), methyl vinyl ketone (157,158), acrolein (157), and sodium 2-acrylamido-2-methylpropanesulfonate (159). The reactions have been carried out under conditions spanning from homogeneous reactions in solvent to heterogeneous reactions occurring in the swollen powder or fiber. 

BMI was also used as a crosslinking agent for poly(iminoethylene). The Michael addition takes place with the nucleophilic nitrogen of the imino group and the double bonds of the electrophilic BMI. The Michael addition of BMI is now adopted as a crosslinking reaction for polymers with amino end groups [2]. 

A variety of routes for incorporation of the succinimide group into a polymer backbone are provided by the use of bis(maleimide) monomers (8 Scheme 5). Examples include Michael addition of diamines or dithiols (or H2S) to produce poly(imides) (9) (B-80MI11101), and photopolymerization (via the triplet state) to prepare cyclopolymers (10) (73PAC213) having molecular weights of about 30 000. 

Michael addition of amines to bis(acrylamides) has provided a versatile method for the preparation of poly(amidoamines) (70MH1102). A wide variety of piperazine-containing polyamides may be prepared by this route when a piperazine, 1,4-diacryloylpiperazine... 

The anion generated by a Michael addition can also be trapped by another Michael addition. Obviously, continued repetition of this process produces polymeric esters, nitriles, etc., in a typical anionic poly-... 

Leong et al. evaluated a hyperbranched poly(amino ester) synthesized in a novel A3+2BB B approach by Michael addition polymerization of trimethylol-propane triacrylate (TMPTA) (A3-type monomer, triacrylate), with a double molar of l-(2-aminoethyl) piperazine (AEPZ) (BB B -type monomer, trifunctional amine) (Fig. 11) [127]. To check its DNA condensation behavior and cytotoxicity, the poly(TMPTAl-AEPZ2) obtained was protonated. Due to the protonation ability of... 

Poly(amidoamine)-(PAMAM-Starburst)-Monodendrons Among the first Starburst (Cascade) syntheses we performed in the early 1980s [83] involved partially masked (differentiated) initiator cores. For example dodecyl-amine, hydroxyalkyl amines or partially protected alkylene diamines were used as initiator cores and submitted to sequential (a) Michael addition with methyl acrylate followed by (b) reaction with an excess of ethylene diamine to give in situ branch cell construction in a divergent manner. The resulting products were core functionalized monodendrons as shown below ... 

The formation of poly substituted tetrahydropyran-4-ones through a Pd-catalysed intramolecular Michael addition of (3-hydroxyenones proceeds with the retention of stereocentres in the enones. The route is simple and is particularly attractive for the synthesis of the 2,6-a ft -substituted heterocycles (Scheme 26) <06CEJ7190>. 

Copper compounds are catalysts for the Michael addition reaction (249), olefin dimerizations (245, 248), the polymerization of propylene sulfide (142), and the preparation of straight-chain poly phenol ethers by oxidation of 2,6-dimethylphenol in the presence of ethyl- or phenyl-copper (209a). Pentafluorophenylcopper tetramer is an intriguing catalyst for the rearrangement of highly strained polycyclic molecules (116). The copper compound promotes the cleavage of different bonds in 1,2,2-tri-methylbicyclo[1.1.0]butane compared to ruthenium or rhodium complexes. Methylcopper also catalyzes the decomposition of tetramethyllead in alcohol solution (78, 81). 

The reaction involves the amine-catalyzed conversion of an aldehyde into a nitroalkene by reaction with nitromethane followed by a transition-metal-catalyzed Michael addition of p-dicarbonyl compounds in the same reaction vessel. Typically, amine catalysts and nickel complexes are incompatible due to their tendency to chelate and to render each other inactive. However, microencapsulation of poly(ethyleneimine) (PEI) forms catalyst 140, which can successfully be used in tandem with the nickel-based catalyst 141 (Figure 3.6). 

Scheme 14.2 Divergent synthesis of poly(propylene imine) dendrimers (A and B) and possible side reactions resulting in defects and chain termination (C missed Michael additions D cyclisation).

Poly(4-tert-butylstyrene) copolymers containing nucleophilic catalysts or ligands can be prepared by modification of 120 and are also useful in latent biphasic catalysis [166]. For example, a triarylphosphine can be attached to a PtBS (132) support and can be used to catalyze the Michael addition of 2-ni-tropropane to methyl acrylate (Eq. 69). 

Michael addition Organo[Pg.777]

Michael additions of 2-nitropropane to methyl acrylate with soluble, diphenyl-phosphine-functionalized poly(4-tert-butylstyrene) copolymers as nucleophilic catalysts were investigated by Bergbreiter and li [Eq. (9)] [22]. The catalytic reactions were performed in a monophasic system consisting of a mixture of ethanol and heptane at room temperature. After 24 h, a small amount of water was added and phase separation occurred. With this water-induced Hquid/Hquid phase separation, the polymeric catalyst could be recycled and successfully applied again in a catalytic cycle. UV-Vis spectroscopy showed that the catalyst was quantitatively dissolved in the nonpolar, heptane-rich phase. 

The method can be illustrated by the preparation of a poly(amido amine), (PAMAM). These are synthesized using either trifnnctional ammonia (NH3) or tetrafunctional ethylene diamine (EDA), NHjCHjCHjNHj, as the core and EDA and methylacrylate (MA) as the branch monomers. The first step is the Michael addition of MA to ammonia or EDA followed by the amidation of each carboxymethyl group using EDA. 

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