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Nicotinamide Coenzyme Models, II. Bis(methoxycarbonyl)‐ N,N ′‐dimethyl[2.2](2,5)pyridiniophane Diiodides: Preparation, Structure, and Reduction to Semi‐Reduced Systems
Author(s) -
Hasselbach HansJoachim,
Krieger Claus,
Decker Matthias,
Staab Heinz A.
Publication year - 1986
Publication title -
liebigs annalen der chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 0170-2041
DOI - 10.1002/jlac.198619860415
Subject(s) - chemistry , sodium dithionite , intramolecular force , adduct , reagent , medicinal chemistry , redox , nmr spectra database , pyridinium , dithionite , aniline , proton nmr , maleic anhydride , stereochemistry , spectral line , inorganic chemistry , organic chemistry , polymer , copolymer , physics , astronomy , enzyme
Abstract From the pyridinophanes 1 – 4 (1) which consist of two nicotinic ester units in the four different orientations possible, by diquaternization the corresponding pyridiniophane diiodides 7 – 10 were obtained. UV and 1 H NMR spectra of these [2.2]paracyclophanes with two positive ring charges are discussed; the molecular structure of the diperchlorate derived from 7 was determined by X‐ray structure analysis. — By sodium dithionite reduction the pyridinium salt 5 with an analogous substitution pattern as 7 – 10 was reduced to the corresponding 1,4‐dihydro compound 6 . 7 reacted with sodium dithionite, however, to the double 1,2‐dihydropyridine system 15 which yielded with maleic anhydride the 1:2‐adduct 16 . Access to the wanted series of semi‐reduced 1,4‐dihydro derivatives 11 – 14 was obtained by the reaction with 6 as the reducing reagent. For 11 and 14 the UV/VIS and 1 H NMR spectra are reported. From first spin saturation transfer 1 H NMR experiments it is concluded that in 14 an intramolecular exchange of redox‐equivalents occurs whereas for the isomer 11 this is not observed under the same conditions.