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Synthesis and preliminary spectroscopic studies into the tautomerism of 3-(arylamino) phthalides
Author
Shah Jahan Mohamed Iqbal
Supervisor
Khoo, Lian Ee
Abstract
A series of 3-(ary1amino)phthalides of the type RC6H4NH-CHC6H4COO, (R=H; 2-OH; 4-OH; 2-OCH3; 4-OCH3; 2-CH3; 4-CH3; 2-Cl; 4-Cl; 2-NO3; 4-NO2) were synthesized and characterized by 'H, "C NMR and IR spectroscopies. Seven of these phthalides are new compounds.
A convenient method for synthesizing the phthalides is by condensation reaction of 2-formylbenzoic acid with the appropriate substituted aromatic amines in methanol.
IR spectroscopic analysis using KBr disc suggest, in the solid state, that the condensation products exist in the phthalide (closed) form instead of a Schiff base (open form).
'H and 13C NMR spectroscopic analysis of the compounds in CDC1, and DMSO-d, confirm that the phthalide form is the predominant form.
In liquid CHCI3, IR spectroscopy was able to detect both the open and close forms of 3-(0-hydroxyani1ino)phthalide and 3-(0-methoxyani1ino)phthalide thus indicating the presence of both ring and chain tautomers. It has been shown qualitatively that these two compounds exist as a form of ring-chain tautomerism with the ring tautomer being more predominant.
A convenient method for synthesizing the phthalides is by condensation reaction of 2-formylbenzoic acid with the appropriate substituted aromatic amines in methanol.
IR spectroscopic analysis using KBr disc suggest, in the solid state, that the condensation products exist in the phthalide (closed) form instead of a Schiff base (open form).
'H and 13C NMR spectroscopic analysis of the compounds in CDC1, and DMSO-d, confirm that the phthalide form is the predominant form.
In liquid CHCI3, IR spectroscopy was able to detect both the open and close forms of 3-(0-hydroxyani1ino)phthalide and 3-(0-methoxyani1ino)phthalide thus indicating the presence of both ring and chain tautomers. It has been shown qualitatively that these two compounds exist as a form of ring-chain tautomerism with the ring tautomer being more predominant.
Date Issued
1996
Call Number
QD471 Sha
Date Submitted
1996