Mesoionic 5-alkyl-4,6-dioxo-l,3-diphenyl-2-(3-vinylbenzylthio)-l,3-diazine (6) was prepared by condensation of alkylmalonic acid (5) with 1,3-diphenyl-2-(3-vinylbenzyl)isothiourea (4) by use of dicyclohexylcarbodiimide (DCC). Homopolymerization of 6 led to new polystyrene derivatives (7) with mesoionic 4,6-diox0-1,3-diazines as pendant groups. UV irradiation of 7 yielded polystyrene derivatives with bis(8-lactam) moieties as pendant groups (8). The change of some physical properties during the irradiation is discussed. 5-Heptyl-4,6-dioxo-l,3-diphenyl-2-(3-methylbenzylthio)-l,3-diazine (11) and 4-heptyl-l-(3-methylbenzylthio)-3,5-dioxo-2,6-diphenyl-2,6-diazabicyclo[2.2.0]hexane (12) as low-molecular-weight model compounds were synthesized for structural analysis.
Mesoionic 5-methyl-4,6-dioxo-3-phenyl-1 -(4-vinylphenyl)-1,3-diazine ( 5 ) was obtained by condensation of 3-phenyl-l-(4-~inylphenyl)formamidine (3) with methylmalonic acid (4). This vinyl-substituted mesoionic heterocyclic compound was polymerized by usual radical initiation and, additionally, by thermally controlled polycycloaddition in solution, yielding two different types of polymers, 6, 7. According to the X-ray diffraction analysis, the structure of a low molecular weight model proves the regioselectivity of the polycycloaddition.
The syntheses of some novel furan-containing monomers, N-[w-(furfurylcarbamoyl)aIkyl]methacrylamide (2) and N-furfurylmethacrylamide (3), and their corresponding polymers are described. Time-conversion measurements of their Diels-Alder reactions with dimethyl butynedioate by means of 'H NMR spectroscopy showed a deviation from pseudo-first-order kinetics. The influence of spacer length on the reaction velocity is explained by steric hindrance and neighboring group effects. No deviations from pseudo-first-order kinetics were observed during the Diels-Alder reaction of the low-molecular-weight model compounds N-[w-(furfurylcarbamoyl)alkyI]isobutyramide (8) and N-furfurylisobutylamide (9) under the same reaction conditions. MS (70 eV): m/z238 (M+), 210 (MC -CO), 142 (M+ -C4H30-CH,-NH-), 96 (Mf -CH-CO-NB-, J = 5,4 Hz, 1 H), 840 (t; --NH-CHz-C4H30, J = 5,
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