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Correlation of dihedral angles with 13 C chemical shifts of quaternary carbon atoms of some phenothiazine derivatives
Author(s) -
Jovanovic Misa V.,
Biehl Edward R.
Publication year - 1987
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570240111
Subject(s) - dihedral angle , chemistry , phenothiazine , ring (chemistry) , crystallography , molecular geometry , chemical shift , carbon 13 nmr , computational chemistry , stereochemistry , molecule , organic chemistry , hydrogen bond , pharmacology , medicine
A direct relationship between the 13 C nmr chemical shifts of the quaternary carbon atoms of the central ring of phenothiazine and the dihedral angle of the respective derivatives has been observed. This correlation allows for the useful and quick estimation of the dihedral angles of novel phenothiazines from readily obtainable 13 C nmr solution measurements. In addition, the change in the dihedral angle appears to be directly related to the S‐C 4 a ‐C 10 a bond angle; however, the C 4 a ‐S‐C 5 a bond angle is not affected by changes in the dihedral angle. This indicates that the “flattening” of the phenothiazine tricyclic ring system is compensated for by the vertical displacement of the sulfur atom, by changes in hybridization of N 10 , and by other angular distortions of the middle ring.