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Über Pterinchemie 51. Mitteilung [1] CNDO‐Rechnungen an Pterin, 6,7‐Dimethyl‐7,8‐dihydropterin und 5‐Formyl‐6, 7‐dimethyl‐5,6,7,8‐tetrahydropterin
Author(s) -
Bieri Jost H.,
Geiger Rudolf E.
Publication year - 1975
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19750580424
Subject(s) - cndo/2 , chemistry , pterin , computational chemistry , chemical shift , electronegativity , stereochemistry , molecule , organic chemistry , cofactor , enzyme
The 13 C‐NMR.‐spectra of 7,8‐dihydropterines and 5,6,7,8‐tetrahydropterines show a large difference in the chemical shifts of the 4a‐ and 8a‐sp 2 ‐carbon atoms. From the CNDO calculations it is apparent that there is a considerable difference in electron density at C(4a) and C(8a) atoms, which leads to a strong polarity of the CC‐Bond. The electron distribution in the highest occupied molecular orbital (HOMO) is discussed.