1,2 , D.A. Narbutaeva 1 , A.M. Karakulova 1 , F.M. Tursunkhodzhaeva 1 , V.I. Vinogradova 1 1) S.Yu. Yunusov Institute of the Chemistry of Plant Substances Academy of sciences of the Republic of Uzbekistan st. Mirzo-Ulugbek, 77, 100170 Tashkent e-mail: j.sherzod.78@mail.ru
2) National University of Uzbekistan named after Mirzo Ulugbek, Universitetskaya st., 4, 100174 Tashkent, Uzbekistan Plant flavonoids have antibacterial, anti-inflammatory, anticancer, capillary-
stabilizing properties associated with antioxidant, membrane-stabilizing effects, and
other properties, which makes them quite valuable synthons for chemical modifications,
biological activity studies, and development of new drugs.
The best known and available flavonoids are quercetin (QV,
1 ) and dihydroquercetin
(DHQ). Continuing our work on the synthesis of bimolecular compounds containing
fragments of flavonoids and isoquinolines, it was studied the Mannich reaction QV (
1 )
involving formaldehyde and 6,7-dimethoxy-1,2,3,4-tetrahydroisoquinolines of various
structures.
The interaction of quercetin (QV) with 1-aryl-(or H)-6,7-dimethoxy-1,2,3,4-
tetrahydroisoquinolines
by
the
Mannich
reaction
synthesized
heterocyclic
monosubstituted conjugates of QV in 75-96% yield. It should be noted that, in contrast
to a similar reaction with dihydroquercetin, that use of quercetin-isoquinoline-
formaldehyde in a ratio of 1:2:2 leads to the reaction progress only at the position 8.
Scheme. Reaction of QV with 6,7-dimethoxy-1,2,3,4-tetrahydroisoquinolines
2 a-k. The structure of the obtained substances was proved on the basis of IR, mass,
1
Н and
13
С NMR spectra.
Among the synthesized conjugates, compounds
3d–3g were found much more
effective in hypoxia and antioxidant than the initial substances, including quercetin, which
indicates the prospects for further obtaining such conjugates and studying their biological
properties.
O
O
OH
OH
OH
HO
OH
CH
2
O
