2- methyl-2-oxazoline

Dihydrofuran (376) and 2,5-dihydrofuran (377) react with nitrile oxides to give furo[2,3-6 ]isoxazoles (378) and furo[3,4-rf]isoxazoles (379), respectively, as cycloadducts. The double bonds of furan, pyrrole and thiophene also react when the nitrile oxide is generated in situ. Thus furan and benzonitrile oxide gave (380), and with 2-methyl-2-oxazoline the cycloadduct (381) was obtained (71AG(E)810). These and related cycloadditions are discussed in Chapter 4.36. 

Typical examples of organic polymers satisfying the above requirements are as follows poly (2-methyl-2-oxazoline) (2), poly(N-vinylpyrrolidone) (3), or poly(N,N-... 

Ring-opening polymerization of 2-methyl-2-oxazoline produces poly( V-acetyl-ethylenimine) (Scheme 2) [24-27], The resulting polymer can be regarded as a... 

The polymerization of 2-methyl-2-oxazoline is a clean reaction, which is not disturbed by chain transfer and termination. In this polymerization, the propagating species having the structure of an oxazolinium salt is not fragile, which is conveniently utilized for syntheses of block copolymers and end-reactive polymers [28],... 

Thus, the ring-opening polymerization of 2-methyl-2-oxazoline followed by the treatment of the resulting oxazolinium propagating end group with 3-aminopropyltriethoxysilane produced successfully triethoxysilyl-terminated poly-oxazoline as shown in Scheme 3 [29]. 

DOL 1.3-Dioxolane, OX oxetane, THF tetrahydrofuran. DMT 3.3-Dimethylthietane, MOXZ 2-methyl-2-oxazoline. 

As previously seen for other POSS derivatives, compounds Ts[(CH2)3X]8 (X = Cl, Br, 1, or SCN) react in the presence of base to give Tio and T12 homologs by cage rearrangement. The iodide, T8[(CH2)3l]8, reacts with 2-methyl-2-oxazoline to give a precursor that can be used for polymer blending (Figure 45). ... 

Symmetric triblock copolymers of the ABA type, where B was PTHF and A poly(2-methyl-2-oxazoline), PMeOx, were prepared by cationic polymerization with trifluoromethanesulfonic anhydride as a difunctional initiator [58]. Subsequent hydrolysis of the PMeOx blocks with HC1 in a methanol/ water mixture resulted in the formation of the corresponding polyethylen-imine blocks (Scheme 20). Samples with relatively low molecular weight distributions were obtained. 

The grafting from methodology was also utilized for the synthesis of poly(4-methylphenoxyphosphazene-g-2-methyl-2-oxazoline) graft copolymers [187]. The synthetic approach involved the thermal polymerization of hexachlorophosphazene, in the presence of aluminum chloride, to give low molecular weight poly(dichlorophosphazene). The chloro groups were subsequently replaced by 4-methylphenoxy groups, followed by partial bromi-... 

Much research has already been devoted in the past couple of years to (i) the immobilization of ATRP active metal catalysts on various supports to allow for catalyst separation and reycycling and (ii) ATRP experiments in pure water as the solvent of choice [62]. A strategy to combine these two demands with an amphiphilic block polymer has recently been presented. Two types of polymeric macroligands where the ligand was covalently linked to the amphiphilic poly(2-oxazo-line)s were prepared. In the case of ruthenium, the triphenylphosphine-functiona-lized poly(2-oxazoline)s described in section 6.2.3.2 were used, whereas in the case of copper as metal, 2,2 -bipyridine functionalized block copolymers were prepared via living cationic polymerization [63] of 2-methyl-2-oxazoline and a bipyridine-functionalized monomer as shown in Scheme 6.8. 

More recently, the scope of using hyperbranched polymers as soluble supports in catalysis has been extended by the synthesis of amphiphilic star polymers bearing a hyperbranched core and amphiphilic diblock graft arms. This approach is based on previous work, where the authors reported the synthesis of a hyperbranched macroinitiator and its successful application in a cationic grafting-from reaction of 2-methyl-2-oxazoline to obtain water-soluble, amphiphilic star polymers [73]. Based on this approach, Nuyken et al. prepared catalyticaUy active star polymers where the transition metal catalysts are located at the core-shell interface. The synthesis is outlined in Scheme 6.10. 

Parallel Optimization and High-Throughput Preparation 2-Methyl-2-oxazoline... 

The sequential addition method also allows the synthesis of many different block copolymers in which the two monomers have different functional groups, such as epoxide with lactone, lactide or cyclic anhydride, cyclic ether with 2-methyl-2-oxazoline, imine or episul-Hde, lactone with lactide or cyclic carbonate, cycloalkene with acetylene, and ferrocenophane with cyclosiloxane [Aida et al., 1985 Barakat et al., 2001 Dreyfuss and Dreyfuss, 1989 Farren et al., 1989 Inoue and Aida, 1989 Keul et al., 1988 Kobayashi et al., 1990a,b,c Massey et al., 1998 Yasuda et al., 1984]. 

Synthesis of a Linear, iV-Acylated Polyethyleneimine Through Cationic Polymerization of 2-Methyl-2-Oxazoline in Bulk... 

In a 100 ml three-necked flask with stirrer and thermometer 1 mol% of p-toluenesul-fonic acid methyl ester (methyl tosylate) are added to 3 g (0.03 mol) of anhydrous 2-methyl-2-oxazoline.The reaction mixture is stirred under nitrogen at 100-120 °C.The bulk polymerization sets in immediately. After 30 min. the viscous polymer melt is poured in a dish where it solidifies within minutes. After cooling to room temperature about 2 grams are dissolved in 20 ml ethanol and precipitated in 500 ml THF.The collected precipitate is dried under vacuum. 

Tsubokawa et al. (44) have reported the grafting of polymeric cationic species of vinyl butyl ether or 2-methyl-2-oxazoline onto aminated silica particles via the termination. However, it is ordinarily difficult to apply the surface termination reac-... 

Another common process involves reaction with C=C or C=N species having adjacent CH2 or CH, groups. Initial attack of the isocyanate is on the electron-rich center of the double bond with subsequent migration and insertion of the CONR group into the CH bond. Suitable reagents include N-alkylated acetamidines, 1-methyl dihydroisoquinoline, and 2-methyl-2-oxazoline [1120-64-5] (35). 

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