Organizing co mmittee

AN APPROACH TO THE OXO-, EPOXY- AND HYDROXY-
DERIVATIVES OF 2E-BENZYLIDENE-24-NOR-ALLOBETULIN 
 
Liana Marselevna Zakirova
1
, Irina Petrovna Baikova
1 
 
1
Ufa Institute of Chemistry of the Ufa Federal Research Centre of the Russian 
Academy of Sciences, Ufa, 450054, Prospekt Oktyabrya, 71, Russian Federation; 
e-mail: [e-mail] 
 
Allobetulin is a natural origin oleanane-type pentacyclic triterpenoid being a part of 
the extractive substances of birch bark. Allobetulin and its derivatives are potent 
bioactive triterpenes with a wide spectrum of biological activities, such as cytotoxic, 
antiviral, antifeedant, immunotropic, antimicrobial and anti-inflammatory combined 
with low toxicity [1]. 
We have modified 3-oxo-24-nor-allobetulin with obtaining 3β-hydroxy-, oxime-, 
methoxyoxime- and lactame- derivatives. The screening of α-glucosidase inhibitory 
activity has shown that 24-nor-allobetulins are more active than allobetulins [2]. 
Reactions and conditions: (a) 4-bromobenzaldehyde, 40% KOH/EtOH, EtOH, r.t., 24 
h.; (b) 40% KOH/EtOH, EtOH, r.t., 24 h. 
Making the Claisen-Schmidt reaction of 3-oxo-24-nor-allobetulin 
1
with 4-
bromobenzaldehyde for several times we have noticed that depending on the reaction 
time two byproducts 
3 
(32 %)
 
and 
4 
(19 %)
 
were formed among the expected 2
E
-
p
-
bromobenzylidene derivative 
2 
with the yield of 49%
. 
When compound 
2
was kept in a 
40% solution of KOH/EtOH without the addition of aldehyde, we observed the 
formation of a mixture of compounds
3
and