2-phenyl-2-oxazoline polymerization

Poly[(i )-2-bromo-5-(tributylstannyl)-3-l4-(4-ethyl-2-oxazolin-2-yl)-phenyl]thiophene [Polymerization of (i )-2-bromo-5-(tributylstannyl)-3-[4-(4-ethyl-2-oxazolin-2-yl)phenyl]thiophene (EOPT-Br,Sn) with Pd2(dba)3 as a catalyst, the CuO-modified Stille-McCullough method] [74]. 

Oxazoline, 2-alkenyl-polymerization, 1, 282 2-Oxazoline, 2,5-dimethyl-5-phenyl-synthesis, 5, 141 Oxazolines... 

Fig. 9.30 a) Normalized MALDI TOF mass spectrum of all fractions (taken after 2 h to 72 h of polymerization time) of poly(2-phenyl-2-oxazoline) freed by dissolving the gold core with NaCN solution and collection of the polymer. The calculated mass of the monomer unit (147.17) is in good agreement with the spacing of the mass signals (AM = 146.93) of the most prominent peaks. Based on ear-... 

Hoogenboom R, Fijten MWM, Schubert US (2004) The effect of temperature on the living cationic polymerization of 2-phenyl-2-oxazoline explored utilizing an automated synthesizer. Macromol Rapid Commun 25 339-343... 

A donor-acceptor zwitterionic polymerization has been mentioned 2-ethyl-oxazoline nucleophilic monomer reacts with the electrophilic N-phenyl maleimide giving a 1 1 adduct which polymerizes upon heating (Fig. 20). A similar reaction was observed between bismaleimide and bis-oxazoline giving a crosslinked network stable up to 300 °C [72]. 

Preliminary results indicate the possibility of preparing ABA block copolymers containing polyacetal (as a middle block) and polyamine blocks 121). When N-t-butylaziridine or 2-phenyl-2-oxazoline are added to a solution of living polyDXP, further polymerization ensues and the products have considerably higher molecular weights than the original polyDXP. NMR analysis confirmed the block character of the product. 

Ring-opening polymerization reactions of several 2-substituted-2-oxazolines (i.e. 2-methyl, 2-ethyl, 2-nonyl, and 2-phenyl) in the presence of methyl tosylate as catalyst have been described by Schubert et al. (Scheme 14.14) [33-35]. The reactions were performed in the temperature range 80 to 200 °C inside a single-mode micro-wave reactor. In a typical run, 25 mL stock solutions of monomer-initiator-solvent were prepared before the polymerization. These stock solutions were divided among different reaction vials so each experiment was performed on a 1-mL scale. 

The large variation in polymerization rates among the various 2-oxazoline monomers has been exploited for the preparation of quasi-diblock copolymers, namely, gradient copolymers with a narrow and steep monomer gradient, by statistical copolymerization of selected monomer combinations exhibiting large differences in reactivity. Such a one-pot quasi-diblock copolymer synthesis was first demonstrated for the statistical copolymerization of 2-phenyl-2-oxazoline and a much less reactive 2-perfluoroalkyl-2-oxazoline [174]. This living CROP (in nitromethane at 120 °C initiated by methyl p-nitrobenzenesulfonate) revealed complete consumption of the 2-phenyl-2-oxazoline after 2 min with only minor incorporation of the fluorinated monomer. Continuation of the polymerization for another 40 h led to full conversion of the fluorinated monomer. The... 

In contrast to HA derivatives, synthesis of Ch derivatives has been less widely reported. Therefore, precise production of Ch derivatives is very important for the investigation of Ch functions and for the development of Ch-related biomaterials. Monomers with 2-ethyl, 2-n-propyl, 2-isopropyl, 2-phenyl, and 2-vinyl groups were designed and synthesized [97]. Polymerization of the 2-ethyl and the 2-vinyl oxazoline monomers effectively proceeded by OTH, providing the corresponding AT-propionyl and N-acryloyl derivatives of Ch in good yields (Table 5). The polymerization reactivity of these monomers depends mainly on the steric bulkiness of the 2-substituent in the oxazoline, i.e., 2-ethyl > 2-vinyl ) 2-n-propyl> 2-isopropyl) 2-phenyl. 

Table 9 Activation energy and frequency factor A for the polymerization of 2-methyl-, 2-ethyl-, 2-phenyl-, and 2-nonyl-2-oxazoline...

Figure 32 Structures of the polymerized oxazoline derivatives 2-(9-decen-1-yl)-1,3-oxazoline 82, 2-(9-decen-1-yl)-4,4-dimethyl-1,3-oxazoline 83, and 2-[4-(10-undecene-1-oxy)phenyl]-1,3-oxazoline 84.

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