Synthesis of selected pyrazine derivatives and their photopyhsical characteristics

2-Phenoxypyrazine, 2-o-methyphenoxypyrazine, 2-m-methylphenoxypyrazine, and 2-p-methylphenoxypyrazine were obtained when 2-chloropyrazine was treated with phenol, o-cresol, m-cresol and p-cresol respectively. Reactions of 2-choropyrazine-5-carboxylic acid methyl ester with phenol, 3-methylphenol and 3-nitrophenol gave 5-phenoxypyrazine- 2-carboxylic acid, 5-m-tolyoxyprazine-2-carboxyclic acid methyl ester and 5-(-3-nitrophenoxy) pyrazine-2-carboxyliic acid methyl ester respectively. 2.5-Dimethyl-3-phenoxypyrazine was obtained when phenol was reacted with 3-chloro- 2,5-dimethylpyrazine. Naphthalenyloxy derivatives were obtained when 2- chloropyrazine reacted with 1 and 2- naphtol respectively. The structures of newly synthesized compounds were spectroscopically characterized. Fluorescence studies showed that compounds 2, 4 and 8 quenched in the presence of oxygen. Compounds 1 and 7 showed the highest fluorescence intensity in alkaline condition. Compound 1, 4 and 8 exhibit the highest emission wavelength in non-polar solvents and falls drastically in polar aprotic solvents. Highest fluorescence intensity was recorded with compounds which have electron donating substituents and has rigid structure