Preparation of new nitrogen-bridged heterocycles. 58. Syntheses and intramolecular arene-pi interactions of 3-(allylthio)- and 3-(propargylthio)thieno[3,4-b]indolizine derivatives.
Various thieno indolizine derivatives having an allylthio or propargylthio group at the 3-position were prepared and their intramolecular arene-pi interactions were investigated. Their 1H-NMR spectra showed significant low-field shifts (delta 0.10-0.34 ppm) to the 5-proton on the thieno indolizine ring, and this effect was the reverse to that observed in 3-(arylmethylthio)thieno indolizines. However, their UV spectra exhibited a characteristic absorption band due to the arene-pi interaction near 430 nm and these values were almost similar to those for arene-arene interaction of 3-arylmethylthio derivatives though their molar extinction coefficients were largely varied by the 3-substituents. Furthermore, both types of gauche conformations in which the intramolecular arene-pi interactions are possible in one form and impossible in the other were confirmed by X-ray analyses of some compounds.
Kakehi
Akikazu
A
Department of Chemistry and Material Engineering, Faculty of Engineering, Shinshu University, Nagano, Japan. akakehi@gipwc.shinshu-u.ac.jp
Suga
Hiroyuki
H
Kaneko
Yoshikazu
Y
Fujii
Tsuneo
T
Tanaka
Nobuaki
N
D018360:Crystallography, X-Ray; D006571:Heterocyclic Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D007202:Indicators and Reagents; D007212:Indolizines / Q000138:chemical synthesis*; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008968:Molecular Conformation; D013055:Spectrophotometry, Infrared; D013056:Spectrophotometry, Ultraviolet
D006571:Heterocyclic Compounds; D007202:Indicators and Reagents; D007212:Indolizines