الفهرس 
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Abstract
This work aimed at utilization of the reactivity of 6,8-
dichloro-2-methyl-4H-chromen-4-one 2 towards nitrogen and
carbon nucleophiles to get new derivatives and evaluated them
for antifungal and antibacterial activities.
Thus, the target compound, 6,8-Dichloro-2-methyl-4Hchromen-
4-one 2 was prepared via acid-catalyzed cyclodehydration
of the β-diketone; 1-(3,5-dichloro-2-hydroxyphenyl)
butane-1,3-dione 1.
The typical active methyl functionality of 6,8-dichloro-2-
methyl-4H-chromen-4-one 2 is utilized to obtain 2-
styrylchromones 3(a-c), pyruvate ester 8 and phthalide 10 via
reactions with aromatic carboxaldehydes, diethyl oxalate and
phthalic anhydride respectively. The phthalide 10 provided
illustrative example to convert a heterocyclic compound to an
aliphatic one 11 via the effect of alcoholic sodium methoxide.
Bromination and cycloaddition reactions under Diels
Alder reaction conditions of 2-styrylchromones afforded vicinal
dibromide 4 and adducts 5(a-g) respectively. This work
presents to the art a typical example of heterocyclic systems
transformations through the conversion of the starting
chromone to coumarin 7 under the influence of thionyl chloride
to afford 2-trichloromethylchromone 6 which was transformed
to coumarin via treatment with aqueous potassium
hydroxide.But-2-enone derivative 13 was isolated from
treatment of 2-methylchromone 2 with ethereal sodium
ethoxide solution as an oxygen nucleophile [cf. Scheme 1].