Preparation and Identification of some new Pyrazolopyrin derivatives and their Polymerizations study

This work describes the synthesis and polymerization properties of some novel polysubstituted fused heterocyclic ring Systems namely; Pyrano [4, 3-C] Pyrazoles and pyrazolo [4, 3-C] Pyridines. Such targeted compounds where designed so as to hybridize the Pyrazole ring with the pyrone and/or pyridine moieties, respectively. The chemistry of the reactions employed in the synthesis of the target compounds together with their chemical behavior, are discussed and the structures of the newly synthesized compounds were confirmed by the IR and 1H-NMR spectral data. A series of copolymers 1-(3,6-dimethyl-4-oxo-1,4-dihydro-5H-pyrazolo [4,3-C] pyridin-5-yl)-1H-pyrrole-2,5-Dione S1, 1-[2-(3,6-dimethyl-4-oxo-1-phenyl-1, 4-dihydro-5H-pyrazolo [4,3-C] pyridin-5-yl)ethyl]-1H-pyrrole- 2,5-Dione S2 and 1-(3, 6-dimethyl-4-oxo-1-phenyl-1,4-dihydro-5H-pyrazolo[4,3-C]pyridin-5-yl)-1H- pyrrole 2,5-Dione S3 with Acrylic acid (AA) were prepared by free radical polymerization in absolute ethanol at 70C˚ using Benzoyl peroxide as initiator. The reactivity ratios of the monomers were determined by Fineman- Ross and Kelen-Tudos methods. Mean Sequence lengths of copolymers are estimated from r1 and r2 values. It shows that the AA unit increases in a linear fashion in the polymer chain as the concentration of AA increases in the monomer feed