Organizing co mmittee

BIOSYNTHESIS OF FLEXIMER ANALOGUES OF PURINE NUCLEOSIDES
,
 BY
-
PRODUCTS OF TRANSGLYCOSYLATION
 
Barbara Z. Eletskaya
1
, Anton F. Mironov
1,2
, Elena S. Matyugina
3
, Anastasya L. 
Khandazhinskaya
3
, Sergey N. Kochetkov
3
, and Irina D. Konstantinova
1
1
Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Moscow, Russian 
Federation 
2
Peoples’ Friendship University of Russia (RUDN University), Moscow, Russian 
Federation 
3
Engelhardt Institute of Molecular Biology, Moscow, Russian Federation 
Fleximer nucleosides are modified nucleosides in which the purine base is divided 
into two heterocyclic fragments with a C-C bond. The flexibility of the heterocyclic 
base allows the molecule to bind better in the active center of the target enzyme. A 
series of six new fleximer nucleosides with carbohydrate residues of two types (ribose 
and 2-deoxyribose, 
4
– 
9
) was obtained using the transglycosylation reaction. The 
reactions were catalyzed by 
E. coli
purine nucleoside phosphorylase
.
It was found that the principle of regioselectivity of transglycosylation in the case of 
fleximer base 
1
is not implemented. For the fleximer base, the formation of
4-aminopyridin- and bis-glycosylation products of the reaction mixture was observed in 
the case of riboside synthesis. Only one minor bis-glycosylation product was formed in 
the synthesis of 2’-deoxyriboside. 
Minor compounds were isolated and the structures were characterized by NMR 
spectroscopy data. Using 
ab initio
and Molecular Modeling methods, it was found that 
due to the non-planarity of the cyclic systems of 4-aminopyridine and pyrazole 
glycosylation of the nitrogen of the pyrimidine ring becomes possible. 
This research was supported by the Russian Science Foundation Project No. 21-13-
0042. 

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Oral presentation
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