[Bisbenzothieno[3,2-b: 2',3'-e]pyridines].
Heating potassium 3-aminobenzo[b]thiophene-2-carboxylate (1) with ethyl propiolate or ethyl 3-ethoxyacrylate in acetic acid yielded the ethyl 2-(6,12-Dihydro-bis[1]benzothieno[3,2-b:2',3'-e]pyridin-6-yl)acetate (3) as main product and 1,4-dihydro-[1]benzothieno[3,2-b]-4-pyridone (2) as by-product. The dihydropyridine (DHP) 3 was dehydrogenated with ammonium cerium nitrate (CAN) to give the pyridine (Py) 4. The half wave potential E(1/2) = 1.64 V showed that 3 was much more stable against oxidizing agents than the reference compound nifedipine with E(1/2) = 1.15 V. Alkaline saponification of the acetic acid ester 4 did not yield the corresponding acetic acid, because decarboxylation took place to form the methylpyridine 5.
Görlitzer
K
K
Institut für Pharmazeutische Chemie der Technischen Universität Braunschweig, Germany. k.goerlitzer@tu-bs.de
Meyer
H
H
D000085:Acetates; D003653:Decarboxylation; D004095:Dihydropyridines / Q000138:chemical synthesis; D007202:Indicators and Reagents; D009682:Magnetic Resonance Spectroscopy; D009543:Nifedipine / Q000138:chemical synthesis; D016877:Oxidants; D011725:Pyridines / Q000138:chemical synthesis*; D021241:Spectrometry, Mass, Electrospray Ionization; D013055:Spectrophotometry, Infrared; D013056:Spectrophotometry, Ultraviolet; D013876:Thiophenes / Q000138:chemical synthesis*
D000085:Acetates; D004095:Dihydropyridines; D007202:Indicators and Reagents; D016877:Oxidants; D011725:Pyridines; D013876:Thiophenes; D009543:Nifedipine