Poster presentation
256
SYNTHESIS OF 6H(Br)-2,4-DICHLOROQUINAZOLINES AND
DIRECTION OF NUCLEOPHILE SUBSTITUTION REACTIONS
R.Z Khudoykulova, I.S. Ortikov, B.J. Elmuradov
S.Yu. Yunusov Institute of the Chemistry of Plant Substances Academy of sciences of the
Republic of Uzbekistan st. Mirzo-Ulugbek, 77, 100170 Tashkent
Currently, the increase in drug resistance of various disease-causing microorganisms
requires the creation of new classes of drugs [1]. Among derivatives of quinazoline and
quinazolinones with different functional groups, it is known from the literature that they
exhibit high activity against harmful microorganisms. In addition,
compounds of this
class are used for anti-obesity, pain relief, and anti-cancer [2,3].
In our study, we obtained the corresponding 2,4-dichloro-6H(bromo)quinazolines
(
3,4
) by reaction of 6H(bromo)quinazoline-2,4-diones (
1,2
)
with chlorinating agents
(POCl
3
+PCl
5
). We carried out nucleophilic substitution reactions with secondary
heterocyclic amines: imidazole, benzimidazole and 2-methylbenzimidazole. In our
previous studies, experiments were conducted with aliphatic
and cyclic secondary
amines in ethanol, and 2,4-disubstituted quinazoline derivatives were obtained. In these
experiments, when we studied the obtained products, we saw that the active chlorine
atom in position 4 was not replaced by amine, but replaced
by ethanol obtained as a
solvent, forming the 4-ethoxy group. and it was observed that the heterocyclic amine
was replaced by the chlorine atom in position 2. We can explain this by the low basicity
of heterocyclic amines and the high activity of the chlorine atom in position 4 for
ssubstitution.
Reactions of 2,4-dichloro-derivatives were carried out in 3,4:Nu - 1:2 ratio in ethanol
(80
0
C) by heating for 6 hours, and new products were obtained in good yields (
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