Preparation of new nitrogen-bridged heterocycles. 53. Syntheses of 3-(benzylthio)thieno[3,4-b]indolizine derivatives and their intramolecular arene-arene interactions.
Various ethyl 1-arylcarbonyl-3-[(un)substituted methylthio]thieno[3,4-b]indolizine-9-carboxylates were synthesized in good yields by a novel methodology in which the S-alkylation of 5-arylcarbonyl-4-ethoxycarbonylmethyl-3-(1-pyridinio)thiophene-2-thiolates with alkyl or benzyl halides, the 1,5-dipolar cyclization of the resulting pyridinium salts in the presence of a base, and the aromatization were performed. In the X-ray analyses of some 3-(benzylthio)thieno[3,4-b]indolizine-9-carboxylates, a gauche and two anti conformers in relation to the exocyclic sulfide linkage were found. Interestingly, all of the 3-(benzylthio)thieno[3,4-b]indolizine derivatives showed significant high-field shifts (delta up to 0.3 ppm) for the 5- and 6-proton signals compared with those of the 3-methylthio derivatives in the (1)H-NMR spectra and exhibited a definite absorption band near 425 nm in their UV spectra, indicating an intramolecular arene-arene interaction between the thieno[3,4-b]indolizine and the phenyl ring.
Kakehi
Akikazu
A
Department of Chemistry and Material Engineering, Faculty of Engineering, Shinshu University, Nagano, Japan. akakehi@gipwc.shinshu-u.ac.jp
Ito
Suketaka
S
Suga
Hiroyuki
H
Miwa
Takeyuki
T
Mori
Takashi
T
Fujii
Tsuneo
T
Tanaka
Nobuaki
N
Kobayashi
Tomoshige
T
D004347:Drug Interactions; D006571:Heterocyclic Compounds / Q000138:chemical synthesis* / Q000493:pharmacokinetics; D007212:Indolizines / Q000138:chemical synthesis* / Q000493:pharmacokinetics; D015394:Molecular Structure; D017672:Nitrogen Compounds / Q000138:chemical synthesis* / Q000493:pharmacokinetics; D013678:Technology, Pharmaceutical / Q000379:methods*
D006571:Heterocyclic Compounds; D007212:Indolizines; D017672:Nitrogen Compounds