2011 - Europe Direct Iasi
2011 - Europe Direct Iasi
2011 - Europe Direct Iasi
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EUROINVENT <strong>2011</strong><br />
R.26.<br />
Title Post-doctoral research<br />
Authors Vasilichia Bejan, Ionel I. Mangalagiu<br />
Institution “Al.I. Cuza” University<br />
Innovation lies in using ultrasound as environmentally<br />
friendly method for the synthesis of new azaheterocyclis<br />
analogous to natural steroids, by [3+2] cycloaddition<br />
reactions via cycloimmonium ylides, being the first study<br />
in the class of this type of ylides.<br />
Biological activity of steroids is closely linked to the<br />
existence of four condensed nuclei and anionic groups on<br />
their skeleton. Starting from this hypothesis, the main<br />
objective was the obtaining of new azasteroids with<br />
phthalazinic, pyridazinic respectively benzo[f]quinolinic<br />
moiety, whose synthesis was made using conventional and<br />
nonconventional (ultrasonication) methods, using<br />
cycloimmonium ylides as reactive species in organic<br />
chemistry. The reaction pathway involves quaternization<br />
of different heterocycles, fallowed by cycloaddition<br />
reactions of ylides (generated in situ from the<br />
corresponding cycloimmonium salts) to variously<br />
Description<br />
dienophiles. In the first step were performed<br />
quaternization reactions of starting heterocycles with<br />
different halogenated derivatives with increased reactivity:<br />
iodoacetamide, methyl and ethyl bromoacetate or allyl<br />
bromide, obtaining the corresponding quaternary salts,<br />
which in alkaline medium (triethylamine) generated in situ<br />
the cycloimmonium ylides.<br />
The [3+2] cycloaddition reactions of phthalazinium ylides<br />
at symmetrical activated cyclic alkene (N-phenyl-and Nethyl-<br />
maleimide, 1,4-naphthoquinone) were studied. For<br />
pyridazinium ylides 1,4-naphthoquinone was used as<br />
dipolarophile, and for benzo[f]quinolinium ylides was<br />
used symmetrical and non-symmetrical activated alkynes<br />
(dimethyl acetylendicarboxylate and ethyl propiolate). All<br />
the reactions were carried out under classical conditions<br />
and ultrasounds irradition. Use of ultrasound in the<br />
synthesis of new azaheterocyclic derivatives proved to be<br />
a direct and effective method, also being an<br />
environmentally friendly method, by reducing the solvent<br />
and energy consumption.<br />
Innovative Researches<br />
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