Synthesis and Polymerization Studies of New Azaethylene Monomers Carrying Electron-Acceptor Groups on Nitrogen.

摘要

To explore the polymerizability of C=N monomers, the following compounds were synthesized: 2-phenylazaethylenecarbonitrile (benzylidenecyanamide; (1), 2-tert-butylazaethylenecarbonitrile (pivalidenecyanamide; (2), Methyl 2-phenylazaethylenyl sulfone (N-(methylsulfonyl)benzylideneamine; (3), ethyl 2-phenylazaethylenecarboxylate (N-carbethoxybenzylideneamine; (4), and ethyl 2-tert-butylazaethylenecarboxylate (N-carbethoxypivalideneamine; (5). Their electrophilic character was appraised using hydrolysis rates and NMR data. Monomer 1 homopolymerized in high yield under both anionic and free-radical conditions to yield a low molecular weight polymer (DP=8). Monomer 2 polymerized poorly anionically and free radically. Monomer 4 oligomerized in low yield with weak bases. Compounds 3 and 5 did not polymerize. Low polymerizability of these compounds is ascribed to the required bulky substituent on carbon, and only the most electrophilic imine with a small cyano substituent on nitrogen and a phenyl substituent on carbon is able to oligomerize effectively. Reprints.(JS)