6-Aryl- and 6,7-diaryl-1,3-dimethyl-1H-perimidin-2(3H)-ones: synthesis, conformational stability, crystal structure and optical properties

Abstract

6-Bromo- and 6,7-dibromo-1,3-dimethyl-1H-perimidin-2(3H)-ones were arylated with arylboronic acids under Suzuki–Miyaura reaction conditions to afford 6-aryl-, 6-bromo-7-aryl- and 6,7-diaryl-1,3-dimethyl-1H-perimidin-2(3H)-ones. A comparison of the X-ray structural parameters of peri-diaryl derivatives of 1,3-dimethyl-1H-perimidin-2(3H)-one, naphthalene and 1,8-bis(dimethylamino)naphthalene (proton sponge) was performed. Based on the data of dynamic 1H NMR spectroscopy and quantum-chemical calculations, barriers to syn/anti-isomerization of 6,7-diaryl-1,3-dimethyl-1H-perimidin-2(3H)-ones were estimated. The optical properties of 6-aryl- and 6,7-diaryl-1,3-dimethyl-1H-perimidin-2(3H)-ones as structural analogs of fluorophoric 6-aryl- and 6,7-diaryl-1,8-naphthalimides were studied.