Synthesis and basicity of 2,6-di-[2-(heteroaryl)vinyl]pyridines
摘要:
The synthesis and spectroscopic characterization of 2,6-di-[2-(heteroalyl)vinyl]pyridines (heteroaryl = 2-furyl, 2-thienyl, 2-pyridyl, 2-thiazolyl) is reported. The pKa of the above pyridine derivatives measured spectrophotometrically are coincident with those measured spectrofluorimetrically, indicating no acid-base re-equilibration in the excited state. NMR spectroscopy provides evidence for the central pyridine ring nitrogen as the site of first protonation in the tri-pyridine derivative. (C) 1998 Elsevier Science Ltd. All rights reserved.