Poly(1,3,4-oxadiazoles). IV. Poly(1,3,4-oxadiazoles) containing pyridine rings was written by Iwakura, Yoshio;Uno, Keikichi;Hara, Shigeyoshi. And the article was included in Makromolekulare Chemie in 1967.SDS of cas: 15420-02-7 This article mentions the following:
Poly(1,3,4-oxadiazoles), which have both thermostability and solubility in organic solvents, are formed by the polycondensation of pyridine dicarboxylic dihydrazides in fuming H2SO4 or polyphosphoric acid (I). The resulting polymers contain pyridine rings and have low mol. weight Thus, 4 g. isocinchomeronic dihydrazide was dissolved with gradual heating in 60 g. I. Heating was continued for 2 hrs. at 120° and 6 hrs. at 180°. The mixture turned dark brown in color. The product was precipitated and washed in H2O, allowed to stand overnight in dilute Na2CO3 solution, H2O-washed, and vacuum dried at 70° to yield 3.2 g. poly(pyridine-5,2-diyl-1,3,4-oxadiazole-2,5-diyl) (II), sp. viscosity 0.16 (0.2 g./100 ml. 95% H2SO4, 30°). [TABLE OMITTED] Similar polymers were prepared from the solution polycondensation of dinicotinic, 2,6-dimethyldinicotinic, dipicolinic, and dipicolinic terephthalic dihydrazides. Polycondensation in fuming H2SO4 gave considerably lower yields. Differences were observed between the ir spectrum of II and that of authentic II prepared by the cyclodehydration of poly(isocinchomeronic hydrazide) in fuming H2SO4. The ir spectrum of II relatively agreed with that of a model compound, 2,5-di-3-pyridyl-1,3,4-oxadiazole, m. 185-5.5°, prepared by condensing nicotinic acid with hydrazine sulfate in fuming H2SO4. Another model compound, 2,5-di-4-pyridyl-1,3,4-oxadiazole, m. 184.5-5°, was similarly prepared from isonicotinic acid. Brittle films of the various polymers were cast from ClCHCO2H and showed moderate solubility in H2SO4 and HCO2H. In the experiment, the researchers used many compounds, for example, 2,5-Di(pyridin-4-yl)-1,3,4-oxadiazole (cas: 15420-02-7SDS of cas: 15420-02-7).
2,5-Di(pyridin-4-yl)-1,3,4-oxadiazole (cas: 15420-02-7) belongs to pyridine derivatives. Pyridine’s the lone pair does not contribute to the aromatic system but importantly influences the chemical properties of pyridine, as it easily supports bond formation via an electrophilic attack. Pyridine, its benzo and pyridine-based compounds play diverse roles in organic chemistry. Pyridine-based materials are valued for their optical and physical properties as well as their medical potential. SDS of cas: 15420-02-7