الفهرس | Only 14 pages are availabe for public view |
Abstract The thesis aiming to synthesis of some new coumarins which might have biological activity and the chemical behaviours toward different nucleophilic and electrophilic reagents under different reaction conditions. The thesis divided into two parts The first part Dealing with the synthesis of 4-hydroxy 6-methyl coumarin (1) and it’s reactivity towards aromatic aldehydes namely p-anisaldehyde and piperonal to give compounds (2 & 3) . Base catalyzed addition of carbanion on 3-arylidine and bis coumarin (2a) & (3b) afford the coumarin derivatives (4-6) . Also the stability of pyrone ring has been investigated under action of methoxide , ammonium acetate , methyl amine , p-toludine , hydrazine , phenyl hydrazine and hydroxyl amine to give compounds (7-14) respectively. The second part Deals with the behaviour of 4-hydroxy 6-methyl coumarin toward electrophilic reagents under phase transfer catalysis conditions such as allyl chloride , benzyl chloride , p-nitrobenzyl chloride and ethyl bromoacetate to give the o-alkylated a.1d /or acylated compounds (16-19) . One pot phase transfer catalysis reaction of coumarin (1) with benzoyl chloride and p-nitrobenzoyl chloride in the presence of carbon disulphide affords dithiolate derivatives (20-22) . Reaction of coumarin (1) with phenyl isothiocyanate in different equimolar amount affords the coumarin and quinolone derivatives (23&24) The structure of all new products have been established by elemental analysis , infrared , nuclear magnetic resonance and mass spectra. |