1H, 13C, and 15N nuclear magnetic resonance studies on the tautomerism of the Schiff's bases of 3-acetyl-6-methyl-2H-pyran-2,4(3H)-dione and 3,5-diacetyltetrahydropyran-2,4,6-trione

1982 ◽  
pp. 513 ◽  
Author(s):  
Sau-Fun Tan ◽  
Kok-Peng Ang ◽  
H. L. Jayachandran ◽  
Alan J. Jones ◽  
William R. Begg
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Schiff’S Bases ◽  
Magnetic Resonance Studies ◽  
Schiff's Bases ◽  
Nuclear Magnetic

A series of Schiff's bases and secondary amine derivatives from 3-formyl-10-methylphenothiazine

1967 ◽  
Vol 45 (7) ◽  
pp. 745-749 ◽  
Author(s):  
W. Kremers ◽  
J. W. Steele
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Infrared Spectra ◽  
Model Compound ◽  
Secondary Amines ◽  
Schiff’S Bases ◽  
Schiff's Bases ◽  
Nuclear Magnetic Resonance Spectra ◽  
Group A ◽  
Nuclear Magnetic

The various recorded methods of synthesizing 10-methylphenothiazine were reviewed, and an improved process is suggested which gives consistent yields of 50–60% purified product. A series of bis-Schiff's bases was prepared by condensation of 3-formyl-10-methylphenothiazine with a number of diamines, and reduction of this series yielded a corresponding series of bis-secondary amines. The secondary amines did not show an NH absorption band in the infrared spectra unless considerably higher than normal concentrations were used, but nuclear magnetic resonance studies in deuteriochloroform confirmed the existence of the ―CH2NH― group. A model compound of the same type (namely, 3-phenyliminomethylene-10-methyl-phenothiazine) was synthesized, and it was found to exhibit exactly the same effects in the infrared spectra and in the nuclear magnetic resonance spectra in deuteriochloroform. In dimethyl sulfoxide-d6, the model compound showed clear evidence of coupling between the NH and the adjacent methylene group, an effect which is rarely seen.Quaternization of the secondary amines was unsuccessful in all but a few cases.

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