الفهرس 
III. LITERATURE SURVEYOnly 14 pages are availabe for public view
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Abstract
Recognizing the importance of the application of green chemistry
principles in organic synthesis for reducing the effects of chemical
processes on environmental balance and human health, the author in this
work intended to utilize some of green chemistry principles that eliminate
or reduce solvents wherever possible or otherwise use inorganic support
in order to create various manifolds of new five and six membered ring
systems including sulfone moiety (which have expected useful
pharmacological properties) through enaminone reactions enhanced by a
green technology such as microwave irradiation in a rapidly, safely and
an environmentally friendly manner. In addition to, ultrasonic-assisted
organic synthesis as a green synthetic approach is a powerful technique.
The thesis contains two main parts; the first part is divided to three
sections;
Section 1.
Entitled “Microwave-assisted regioselective route to some novel
pyrazole and pyrazolo[3,4-d]pyridazine derivatives linked to sulfonyl
dibenzene moiety as antimicrobial agents.”
Reaction of 1-acetyl-4-(phenylsulfonyl)benzene 1 with
dimethylformamide-dimethylacetal (DMFDMA) under microwave
irradiation for 20 min. provided the corresponding E-3-(dimethylamino)-
1-(4-(phenylsulfonyl)phenyl) prop-2-en-1-one 2 in 90% yield compared
with conventional heating reaction in dry toluene for 12 hr in 70% yield
(Chart 1).
II. Summary
2
O S O
O Me
MW or reflux
+ Me2N
OMe
OMe
O S O
O
1 2
NMe2
Chart 1
In this section the reactivity of enaminones with synthesis of novel
pyrazole derivatives incorporating sulfone moiety using synthetic talc as
an efficient basic catalyst under microwave irradiation via 1,3-dipolar
cycloaddition reaction in comparing with conventional heating methods
by the action of synthetic talc as catalyst in refluxing chloroform was
investigated.
Our first efforts were the determination of the optimal conditions
on catalysts efficiency for this reaction. Initially, a model reaction of E-3-
(dimethylamino)-1-(4-(phenylsulfonyl)phenyl) prop-2-en-1-one 2 was
treated with 1-(2-phenylhydrazono)-1-chloropropan-2-one 3a in absence
or in presence of different catalysts without solvent under microwave
irradiation.
The results show that synthetic talc was the most effective among
the solid supports tested to promote the reaction highest yields and
shortest time (Chart 2).
II. Summary
3
Thus, when enaminone 2 was allowed to react with nitrilimines 4a-c
[liberated, in situ, from the corresponding 1-(2-Substituted
phenylhydrazono)-1-chloropropan-2-one 3a-c in presence of synthetic
talc under microwave irradiation or conventional heating by the action of
synthetic talc in refluxing CHCl3], afforded, in each case, the presumable
pyrazoles (6a-c) in high yields (Chart 2).
Similarly, enaminone 2 was treated with ethyl-2-(2-
Substitutedphenylhydrazono)-2-chloroacetate 10a-c or 2-(2-mtolylhydrazono)-
2-bromo-1-(thiophen-2-yl)ethanone 15 under the same
conditions of microwave irradiation and conventional heating, afforded
pyrazoles 12a-c and 17 derivatives in good to excellent yields and shorter
reaction time comparing with traditional conditions (Chart 2).
The structures of the latter products 12a-c and 17 were established
on the basis of their elemental analyses and spectral data, in addition to
further confirmed chemically via the reaction of compounds 6a-c and 17
with hydrazine under microwave irradiation in presence of ethanol or
refluxing in ethanol, to afford the pyrazolo[3,4-d]pyridazine derivatives
9a-c and 18, respectively in excellent yields by loss of two moles of
water (Chart 3).
II. Summary
4
O S O
O
2
O
Cl
N.