1-t-Butylaziridine

Triflic anhydride is an efficient initiator used in thfe living polymerization of oxolane 60), and bifunctional poly-THF oligomers can be further employed to initiate the polymerization of t-butylaziridine yielding polymers with aziridinium sites at both ends of their chain61 which can be reacted with methacrylic acid. 

Monofunctional polymers of A -t-butylaziridine containing polymerizable group (macromonomers) were prepared by initiation of the polymerization with methyltriflate and termination with methacrylic acid [168]. 

The choice of monomers is limited not only by the order of nucleophilicity. The first block should carry a living end capable to initiate the polymerization of the second monomer by addition. Up to now, only a few systems are known to meet these requirements. Thus, in the presence of stable counterions, living polymerization of DXL 109), DXP 109), XHF 110,111,112), N-t-butylaziridine 113), 1,3,3-trimethylazeti-dine 1W), conidine 115) and l-(2-phenylethyl)-2-methylaziridine 116) may proceed. The last four monomers are highly nucleophilic cyclic amines and there is not too much chance that the active species derived from this class of monomers would initiate polymerization of other, less nucleophilic monomers. Thus, attempts directed toward the preparation of block copolymers of cyclic ethers or acetals were employed... 

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. 

This method requires not only strictly living conditions but also the quantitative conversion of the living growing centers into reactive end-groups. At present, living polymerization of THF and 1-t-butylaziridine have been used for this purpose, e.g. ... 

Alkyl-l-t-butylaziridines. These 1,2-disubstituted aziridines (3) can be obtained by chlorination of imines of aldehydes (1) with 2 eq. of NCS to form (2) followed by reduction with lithium aluminum hydride. ... 

Termination of the cationic ring-opening polymerization of N-t-butylaziridine with methacrylic acid irields macromonomers (531). 

Cycloadditions t-Butylsulfonylamine 75 reacts with the diazoalkane derivative 76 at —78 C to give 2,3-di-t-butylaziridine 1,1-dioxide 77 in 43 % yield . 

Termination of the cationic ring-opening polymerization of iV-t-butylaziridine with methacrylic acid yields macromonomers according to equation (20). Because N-t-butylaziridine is sterically hindered, polymerization is not complicated by the transfer reaction of two growing chains that results in one chain growing in two directions and one dead chain. 

The three-membered aziridine rings and the four-membered azetidine rings can only be polymerized by a cationic mechanism." Although triflic anhydride initiation does not lead to bifunctional polymers, monofunctional telechelics can be obtained from t-butylaziridine (TBA) using... 

Poly(methyl methacrylate -block-t-butylaziridine) ABA type copolymer with MW 12000 butylaziridine (B) and MW 16000 Ambient to 600 CO, CH4, CO2, ethene, propene, isobutene, aziridine, methanol, methyl methacrylate, cc-methylstyrene, 2-phenyl-2-butene, 1 -t-butylamino-2-isopropenylamino-ethane, 2-r-butylaminoethyl-ethyl-isopropenylamine, 2-aminoethyl-2-r-butylaminoethyl-isopropenylamine, oligomers - principally butylaziridine based 287... 

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