Synthesis and transformations of norbornyl acrylates

Article abstract of DOI:10.1023/A:1013961731999

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.

Full text of DOI:10.1023/A:1013961731999

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

SYNTHESIS AND TRANSFORMATIONS OF NORBORNYL ACRYLATES
Table 1. H NMR spectra of compounds synthesized, , ppm
1701
H10
1
Compd.
no.
H1
H2
H3
H4
H5
H6
H7
H8
H9
I
II
VII
VIII
XIII
XIV
2.20
2.20
2.45
2.12
2.50
2.55
4.60
4.60
4.75
4.72
4.05
4.15
1.40
1.45
1.30
1.48
1.48
1.48
2.20
2.25
2.45
2.12
2.55
2.60
1.0
5.0
1.9
5.1
1.9
3.9
1.10
1.15
1.40
1.90
1.40
1.90
1.13
1.15
1.00
1.30
1.30
1.30
6.23
6.18
2.25
2.37
4.70
4.65
5.75
5.76
1.10
1.27
0.85
1.14
1.10
Table 2. Yields, physical properties and elemental analyses of norbornyl acrylates I VI
Found, %
Calculated, %
Compd.
no.
bp,
(30 mm Hg)
C
Yield, %
d240
n2D0
Formula
C
H
C
H
I
II
III
IV
V
75
68
65
59
60
54
108
1.0318
0.9966
0.9863
0.9710
0.9827
0.9821
1.4740
1.4755
1.4785
1.4792
1.4804
1.4860
72.24
73.29
74.17
74.90
74.92
75.60
8.46
8.91
9.30
9.61
9.65
9.95
C10H14O2
C11H16O2
C12H18O2
C13H20O2
C13H20O2
C14H22O2
72.26
73.30
74.19
74.96
74.96
75.63
8.89
8.94
9.33
9.67
9.67
9.97
117 118
136 137
116 117
159 160
179 180
VI
along the known procedure [10]. We obtained as a
result norbornyl propionates VII XII in 94 95%
yield and bicyclic alcohols XIII XVIII in 96 98%
yield.
As initial compounds were used the following
bicyclo hydrocarbons: bicyclo[2.2.1]hept-2-ene,
5-methyl-, 5-ethyl-, 5-isopropyl-, and 5-butylbicyclo-
[2.2.1]hept-2-enes. The compounds were obtained by
condensation of olefins with cyclopentadiene [11].
The acrylic acid applied corresponded to specifica-
tions TU 6-09.413-83.
The purity of compounds synthesized after distilla-
tion was 99 99.8%. Their isomeric composition and
structure was investigated by means GLC, IR, and
NMR spectroscopy. In the IR spectra of all acrylates
The synthesis of acrylates and their hydrogenation
were carried out in a rotating pressure reactor of
stainless steel; the hydrolysis of propionates was
performed in the common glass vessels.
1
appears a strong band in the 970 cm region char-
acteristic of an exo isomer. The absorption in the
1
region 1725 1730 and 1240 1245 cm evidences the
presence of ester groups in the molecules, and the
1
absorption bands at 815 and 890 cm in combination
2-exo-Bicyclo[2.2.1]heptyl acrylate (I). A mix-
ture of 47.1 g of norbornene, 45 g of acrylic acid,
and 0.045 g of hydroquinone was heated in the pres-
sure reactor to 170 C for 3 h. The fractional distilla-
tion of the resulting mixture afforded 61.9 g (75%) of
compound I.
1
with a band at 1640 cm prove the presence of a
vinyl group.
1H NMR spectra of some compounds synthesized
are presented in Table 1.
As seen from Table 1, in the spectra of acrylates
I, II are observed signals at 5.75 6.23 ppm character-
istic of vinyl protons; in the spectra of alcohols XIII,
XIV appear the signals of hydroxy group protons
at 4.65 4.70 ppm; the endo-protons H2 and H 5
resonate in the 4.0 5.0 ppm region.
Compounds II VI were prepared similarly
(Table 2).
2-exo-Bicyclo[2.2.1]heptyl propionate (VII).
A mixture of 33.2 g of compound I, 3.32 g of catal-
yst Ni on kieselguhr activated in a flow of hydrogen,
and 0.33 g of hydroquinone was charged in the pres-
sure reactor, and hydrogen was fed in to the pressure
of 100 atm. The reactor was heated to 120 C for
2.5 h. After the hydrogen was no long consumed the
EXPERIMENTAL
The conditions used for GLC analysis and record-
1
ing of H,13C, and IR spectra were described in our
preceding communication [8].
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 37 No. 12 2001

1702
MAMEDOV et al.
Table 3. Yields, physical properties and elemental analyses of norbornyl propionates VII XII
Found, %
Calculated, %
Compd.
no.
bp,
(30 mm Hg)
C
Yield, %
d240
n2D0
Formula
C
H
C
H
VII
VIII
IX
X
XI
94
96
98
96
97
98
109.5
119 120
137.0 137.5
145 146
156.5 157.0
177 178
0.9996
0.9894
0.9884
0.9760
0.9868
0.9876
1.4596
1.4620
1.4630
1.4600
1.4655
1.4666
71.32
72.45
73.40
74.20
74.20
75.60
9.56
9.93
10.25
10.51
10.50
10.74
C10H16O2
C11H18O2
C12H20O2
C13H22O2
C13H22O2
C14H24O2
71.39
72.49
73.43
74.24
74.24
75.63
9.58
9.95
10.27
10.54
10.54
10.78
XII
Table 4. Yields, physical properties and elemental analyses of bicyclic alcohols XIII XVIII
Compd.
no.
Found, %
Calculated, %
bp,
(30 mm Hg)
C
Yield, %
d240
n2D0
Formula
C
H
C
H
a
XIII
XIV
XV
XVI
XVII
XVIII
98
97
94
94
95
95
74.91
76.11
77.00
77.81
77.72
78.50
10.72
11.16
11.50
11.72
11.72
11.94
C7H12O
C8H14O
C9H16O
C10H18O
C10H18O
C11H20O
74.95
76.14
77.08
77.86
77.86
78.51
10.78
11.18
11.50
11.76
11.76
11.97
73 74
98 99
122 123
117 118
142 143
0.9988
0.9950
0.9875
0.9745
0.9738
1.4826
1.4836
1.4890
1.4790
1.4896
a
Melting point of compound XIII 127 C is consistent with the published data [12].
catalyst was filtered off, and the reaction mixture was
subjected to fractional distillation. Compound VII
was obtained in 94% yield.
lov, N.S., Dokl. Akad. Nauk Belarus. SSR, 1967,
vol. 2, no. 2, pp. 140 144.
3. Golding, B., Khimiya i tekhnologiya polimernykh
materialov (Chemistry and Technology of Polymeric
Materials), Leningrad: Khimiya, 1963, p. 422.
4. Japan Patent 61-53242, 1986; Ref. Zh. Khim., 1986,
9N66P.
5. Japan Patent 60-226513, 1986; Ref. Zh. Khim., 1986,
19S69P.
6. Sadykhov, Sh.G., Gumbatov, E.G., Mamedov, A.A.,
and Musaeva, F.M., Azerb. Khim. Zh., 1983, no. 3,
pp. 57 59.
Compounds VIII XII were prepared in the similar
way (Table 3).
2-exo-Bicyclo[2.2.1]heptanol (XIII). To a mix-
ture of 16.8 g of compound VII and 25 ml of ethanol
at heating to 70 C while vigorous stirring was added
within 1 h 20 ml of 20% NaOH solution. The stirring
was continued for 1 h more. The reaction mixture
was extracted with ether, the extract was dried with
anhydrous CaCl2, the solvent was distilled off. We
obtained 11 g (98%) of compound XIII.
7. Mamedov, M. K., Neftekhimiya, 1997, vol. 37, no. 1,
pp. 76 80.
8. Mamedov, M. K., Zh. Org. Khim., 1997, vol. 33,
no. 2, pp. 192 196.
9. Mamedov, M. K., Azerb. Khim. Zh., 1998, no. 3,
pp. 74 78.
Bicyclic alcohols XIV XVIII were prepared in
the similar way; their characteristics are given in
Table 4.
10. Mamedov, M. K., Zh. Org. Khim., 1998, vol. 34,
no. 2, pp. 206 210.
11. Mamedov, M. K., Neftekhimiya, 1991, vol. 31, no. 3,
pp. 350 354.
12. Komppa, G. and Beckmann, E., Lieb. Ann., 1934,
vol. 512, p. 181.
REFERENCES
1. Tekhnologiya
plasticheskikh
mass
(Plastics
Technology), Korshak, V.V., Ed., Moscow: Khimiya,
1972, pp. 50 70.
2. Emel,yanov, N.P., Naumova, L.V., and Koz-
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 37 No. 12 2001