Russian Journal of Organic Chemistry, Vol. 37, No. 12, 2001, pp. 1700 1702. Translated from Zhurnal Organicheskoi Khimii, Vol. 37, No. 12, 2001,
pp. 1781 1783.
Original Russian Text Copyright
2001 by Mamedov, Nabieva, Dzhafarova.
Synthesis and Transformations of Norbornyl Acrylates
M. K. Mamedov, E. K. Nabieva, and E. N. Dzhafarova
Institute of Petrochemical Processes, Academy of Sciences of Azerdaidzhan, Baku, 370025 Azerdaidzhan
Received September 26, 2000
Abstract A simple and more environmentally friendly procedure than that traditionally used was developed
for preparation of esters consisting in acrylic acid addition to bicyclo[2.2.1]hept-2-ene and its 5-alkyl
derivatives. The acrylates obtained were subjected to hydrogenetion followed by hydrolysis of propionic acid
esters. A number of new compounds was obtained; some among them possess a pleasant odor.
Esters of cyclic alcohols and acrylic acid are
successfully used as monomers for plastics [1, 2],
efficient adhesive for dental prostheses [3], com-
pounds for protection from the action of UV light and
paint binder at electronic printing [4], and also in
preparation of nonaqueous polymer materials [5].
prevent the radical polymerization of the acrylic acid
at heating. The conditions of reaction and reagents
ratio were optimized for ester formation; the best
conditions were as follows: temperature 170 C,
molar ratio of bicyclic olefins to acrylic acid 1: 1.25,
reaction time 3 h, hydroquinone in amount of
0.1 wt% to acrylic acid. Under these conditions the
yields of acrylates reach 54 75%.
We developed a simple and more environmentally
friendly procedure than that traditionally used for
preparation of acrylic acid esters by thermal addition
of the acid to bicyclo[2.2.1]hept-2-ene and its 5-exo-
alkyl derivatives. The initial bicycloolefins were
obtained by isomerization of a mixture of the endo
and exo isomers in the presence of AlCl3 in dichloro-
methane solution.
Alkyl substituents in the 5-position negatively
affect the reactivity of the -bond in the bicyclo-
[2.2.1]hept-2-ene ring. The longer is the hydrocarbon
chain of the alkyl substituent, the lower is the yield of
the corresponding acrylate:
H> CH3> CH3CH2> CH3CH2CH2> (CH3)2CH
>CH3(CH2)3CH2.
Aiming at preparation of propionic acid esters
with saturated bicyclic alcohols hydrogenation of
acrylates I VI was perfomed in the presence of Ni on
kieselguhr as catalyst. The hydrogenated esters were
also subjected to hydrolysis by 20% NaOH solution
R = H (I), Me (II), Et (III), i-Pr (IV), Pr (V),
Bu (VI).
Acrylic acid same as saturated monocarboxylic
acids [7 9] stereoselectively adds at heating without
catalyst to bicyclo[2.2.1]hept-2-ene to yield an exo
isomer of ester I. Compound I smells of pleasant
odor with fruit tint and may be used as a component
of synthetic perfumes.
The investigation of the composition and purity of
the esters obtained by GLC revealed that the thermal
addition of acrylic acid to the 5-exo-alkyl derivatives
of norbornene resulted in formation of 5-exo-alkyl-
bicyclo[2.2.1]hept-2-yl exo-acrylates (II VI) as
92 94% of the product and 6-exo-alkylbicyclo[2.2.1]-
hept-2-yl exo-acrylates as 6 8% in the ratio 93: 7.
We used in reaction hyroquinone as inhibitor to
R = H (I, VII, XIII), Me (II, VIII, XIV), Et (III,
IX, XV), i-Pr (IV, X, XVI), Pr (V, XI, XVII), Bu
(VI, XII, XVIII).
1070-4280/01/3712-1700$25.00 2001 MAIK Nauka/Interperiodica