Isolation of ozonides from gas-phase ozonolyses of terpenes

Article abstract of DOI:10.1021/es970602r

Ozonolyses of (-)-β-pinene (1) and of (+)-sabinene (6) in the gas phase afforded the corresponding ozonides 6,6- dimethylbicyclo[3.1.1^1,5]heptane[2-spiro-3]-1,2,4-trioxolane (2) and 5- isopropylbicyclo[3.1.0^1,5]hexane[2-spiro-3]1,2,4-trioxolane (7), which were isolated as mixtures of two diastereomers each. Major products were the corresponding ketones 6,6-dimethyl-2-oxobicyclo[3.1.1^1,5]heptane (3) and 5-isopropyl-2-oxobicyclo[3.1.0^1,5]hexane (8). Additional products were the lactones 7,7-dimethyl-2-oxa-3-oxobicyclo[4.1.1^1,6]octane (4) and 7,7- dimethyl-3-oxa-2-oxobicyclo[4.1.1^1,6]octane (5) derived from β-pinene (1) as well as 6-isopropyl-2-oxa-3-oxobicyclo[4.1.0^1,6]heptane (9) and 6- isopropyl-3-oxa-2-oxobicyclo[4.1.0^1,6]heptane (10) derived from sabinene (6). Ozonolyses of (-)-β-pinene (1) and of (+)-sabinene (6) in the gas phase afforded the corresponding ozonides 6,6-dimethylbicyclo[3.1.1^1,5]heptane[2-spiro-3]-1, 2,4-trioxolane (2) and 5-isopropylbicyclo[3.1.0^1,5]hexane [2-spiro-3]-1,2,4-trioxolane (7), which were isolated as mixtures of two diastereomers each. Major products were the corresponding ketones 6,6-dimethyl-2-oxobicyclo[3.1.1^1,5]heptane (3) and 5-isopropyl-2-oxobicyclo[3.1.0^1,5]hexane (8). Additional products were the lactones 7,7-dimethyl-2-oxa-3-oxobicyclo[4.1.1^1,6]octane (4) and 7,7-dimethyl-3-oxa-2-oxobicyclo[4.1.1^1,6]octane (5) derived from β-pinene (1) as well as 6-isopropyl-2-oxa-3-oxobicyclo[4.1.0^1,6]heptane (9) and 6-isopropyl-3-oxa-2-oxobicyclo[4.1.0^1,6]heptane (10) derived from sabinene (6).

Full text of DOI:10.1021/es970602r

Environ. Sci. Technol. 1998, 32, 647-649
Experimental Section
Isolation of Ozonides from
All reagents and solvents were of commercial grade. 1H NMR
Gas-Phase Ozonolyses of Terpenes
3
spectra were obtained in CDCl with TMS as internal reference
on a Bruker AC 250 instrument. GC analyses were carried
out on a Hewlett-Packard 5890 instrument using the following
conditions: 50 m capillary column SE 54, 50-200 °C at 10
K A R L G R I E S B A U M * A N D
†
V A S I L E M I C L A U S
°
C/ min.
Ozonolysis Procedure. A 6-L two-neck round-bottom
flask, equipped with a septum and a connection to a vacuum
Engler-Bunte-Institut, Bereich Petrochemie,
Universit a¨ t Karlsruhe (TH), D-76128 Karlsruhe, Germany
-
2
I N C H A N J U N G
line was evacuated to 10 Torr at room temperature. The
vacuum line was closed, the liquid substrate was injected
with a syringe, and after ca. 30 min a O
Department of Chemistry, Hanseo University,
Seosan, Chung-Nam, 352-820 Korea
3 2
/ O mixture containing
1
mmol of O / L was slowly injected within 1 min with a gas
3
syringe. After a reaction time of ca. 10 min, the flask was
cooled in an ice-water bath, filled with nitrogen, opened,
and rinsed with ether. From the combined ether solutions
of several runs, ether was distilled off at room temperature
and reduced pressure, and the remaining residue was
separated by flash chromatography on silica gel.
Ozonolyses of (-)-â-pinene (1) and of (+)-sabinene (6)
in the gas phase afforded the corresponding ozonides
1
,5
6
,6-dimethylbicyclo[3.1.1 ]heptane[2-spiro-3]-1,2,4-triox-
1,5
olane (2) and 5-isopropylbicyclo[3.1.0 ]hexane[2-spiro-3]-
,2,4-trioxolane (7), which were isolated as mixtures of
two diastereomers each. Major products were the corre-
sponding ketones 6,6-dimethyl-2-oxobicyclo[3.1.1 ]heptane
3) and 5-isopropyl-2-oxobicyclo[3.1.0 ]hexane (8). Additional
Ozonolysis of (-)-â-Pinene (1). Treatment of 20 mg (0.15
1
mmol) of 1 with 120 mL of a O
mmol of O
0 times. From the residue, a mixture of 2a and 2b as well
3
/ O
2
mixture (containing 0.12
) and workup as described above was repeated
1,5
3
1
1,5
(
as 3-5 have been isolated (solvent: pentane/ ether, 4:1) in
amounts sufficient to get NMR spectra. GC analysis of the
residue showed the presence of 2-5 in the ratios reported.
products were the lactones 7,7-dimethyl-2-oxa-3-oxobi-
1,6
cyclo[4.1.1 ]octane (4) and 7,7-dimethyl-3-oxa-2-oxobi-
1,6
cyclo[4.1.1 ]octane (5) derived from â-pinene (1) as well
1,5
6
,6-Dim ethylbicyclo[3.1.1 ]heptane[2-spiro-3]-1,2,4-
1,6
as 6-isopropyl-2-oxa-3-oxobicyclo[4.1.0 ]heptane (9) and
1
3
trioxolanes (2a and 2b). H NMR: 2a δ 0.93 (s, CH ), 1.23
1,6
6
-isopropyl-3-oxa-2-oxobicyclo[4.1.0 ]heptane (10) de-
(s, CH ), 5.00 (s, OCH OO), 5.07 (s, OCH OO); 2b (21) δ 0.99
3
2
2
rived from sabinene (6).
(s, CH
3
), 1.25 (s, CH
3
), 5.03 (s, OCH
2
2
OO), 5.17 (s, OCH OO);
the intensity ratio of the signals for 2a and 2b was 10:1. GC
) 22.4 min for 2a + 2b. Treatment of the above mixture
t
R
1
with an excess of TPP in CDCl
3
gave 3, as shown by H NMR
Introduction
spectroscopy.
6,6-Dim ethyl-2-oxobicyclo[3.1.11,5]heptane (3). 1H
NMR: δ 0.85 (s, 3H), 1.30 (s, 3H), 1.54 (d, 1H), 1.85-2.63 (m,
Gas-phase ozonolyses of olefins is an area of active research,
particularly with respect to atmospheric ozone chemistry
(
1). Compared with the great number of publications in this
7H); GC t
R
) 22.1 min.
field, there are only very few reports about the formation of
ozonides, and they have been only detected in ozonolysis
reactions of small olefins or in co-ozonolyses of small olefins
and added small carbonyl compounds (2-5). Identifications
of these ozonides were based either on long-path FTIR
analysis by computational subtraction of contributions of
other components to the spectrum (2-4) or by GC/ MS
analysis (5), yet not by isolation and the usual methods of
characterization.
,7-Dim ethyl-2-oxa-3-oxobicyclo[4.1.11,6]octane (4). 1H
7
NMR: δ 0.89 (s, 3H), 1.30 (s, 3H), 1.83-2.02 (m, 2H), 2.11 (d,
J ) 14.09 Hz, 1H), 2.25-2.31 (m, 1H), 2.60-2.70 (m, 1H),
1
3
2.86-2.94 (m, 2H), 4.33 (dd, J ) 5.77 and 4.86 Hz, 1H);
NMR: δ 18.41, 22.19, 26.49, 27.35, 34.02, 41.23, 43.18, 84.08,
174.86; GC t ) 28.4 min.
,7-Dim ethyl-3-oxa-2-oxobicyclo[4.1.11,6]octane (5). 1H
C
R
7
NMR: δ 1.04 (s, 3H), 1.39 (s, 3H), 1.82-1.94 (m, 1H), 2.22-
2.35 (m, 2H), 2.40-2.53 (m, 2H), 2.91-2.97 (m, 1H), 4.27-
4
.35 (m, 1H), 4.70 (dt, J ) 13.09 and 3.58 Hz, 1H); 13C NMR:
Among the olefins examined in gas-phase ozonolyses,
terpenes are the most prominent class of compounds, since
they are emitted from coniferous trees (6) at an estimated
δ 19.79, 20.68, 27.57, 28.48, 40.42, 41.00, 53.34, 66.19, 174.32;
GC t ) 28.8 min.
Ozonolysis of (+)-Sabinene (6). Treatment of 42 mg (0.31
mmol) of 6 with 250 mL of a O / O mixture (containing 0.25
mmol of O ) and workup as described above was repeated
R
8
global rate of 10 t/ a (7). In particular, gas-phase ozonolyses
of â-pinene (1) (8-18) and of sabinene (6) (8, 9, 13, 19) have
been studied by a number of groups, but none of them
reported the detection of ozonides. Recently, we have
ozonized 1 and 6 in the liquid phase, and we have isolated
two diastereomers each of the corresponding stable ozonides
3
2
3
12 times. From the residue, a mixture of 7a and 7b as well
as 8-10 have been isolated (solvent: petroleum/ ether, 95:5)
in amounts sufficient to get NMR spectra. GC analysis of the
residue showed the presence of 7-10 in the ratios reported.
2
and 7 (20). With the help of these authentic samples, which
1
1,5
exhibit characteristic H NMR signals for the CH
2
groups, we
5-Isopropylbicyclo[3.1.0 ]hexane[2-spiro-3]-1,2,4-tri-
1
have now tried to find out whether such ozonides are present
oxolanes (7a and 7b). H NMR: 7a δ 5.07 (s), 5.24 (s); 7b
in the crude products from gas-phase ozonolyses of 1 and
δ 5.07 (s), 5.15 (s); from the intensities of the signals at δ 5.24
6
.
and δ 5.07, a ratio of 2:3 has been calculated. GC t ) 23.1
R
min. Treatment of the above mixture with TPP in CDCl
gave 8, as shown by H NMR spectroscopy.
3
1
*
Corresponding author fax: ++49 721 608-4881.
On leave from Babes-Bolyai University, Department of Chemistry,
5-Isopropyl-2-oxobicyclo[3.1.01,5]hexane (8). 1H NMR:
†
Cluj-Napoca, Roumania.
δ 0.93 (d, J ) 6.72 Hz, 3H), 0.99 (d, J ) 6.80 Hz, 3H), 1.05-1.10
S0013-936X(97)00602-0 CCC: $15.00
Published on Web 01/26/1998

1998 Am erican Chem ical Society
VOL. 32, NO. 5, 1998 / ENVIRONMENTAL SCIENCE & TECHNOLOGY
9
6 4 7

CHART 1
CHART 2
CHART 3
(
(
m, 1H), 1.16-1.20 (m, 1H), 1.51-1.68 (m, 2H), 1.94-2.21
m, 4H); GC t ) 22.7 min.
-Isopropyl-2-oxa-3-oxobicyclo[4.1.01,6]heptane (9). 1
R
6
H
NMR: δ 0.78 (t, J ) 6.80 Hz, 1H), 0.92 (d, J ) 6.42 Hz, 3H),
1
2
.01 (d, J ) 6.05 Hz, 3H), 0.85-1.20 (m), 1.69-1.80 (m, 1H),
.07-2.48 (m, 3H), 3.82 (dd, J ) 6.70 and 2.83 Hz, 1H); 13
C
NMR: δ 17.87, 18.81, 18.82, 21.81, 23.99, 28.68, 34.15, 61.10,
71.10; GC t ) 27.7 min.
-Isopropyl-3-oxa-2-oxobicyclo[4.1.01,6]heptane (10). 1
NMR: δ 1.01 (m, 6H), 0.83-1.31 (m, 2H), 1.60 (t, J ) 4.25 Hz,
1
R
6
H
1
6
2
H), 1.69 (dd, J ) 12.50 and 3.68 Hz, 1H), 4.28 (ddd, J ) 12.03,
13
.17 and 1.50 Hz, 1H); C NMR: δ 14.77, 18.84, 18.93, 20.76,
2.96, 30.88, 35.08, 64.40, 171.56; GC t ) 29.9 min.
R
Results
in the gas phase. The latter reactions have been reported to
give formaldehyde and the corresponding ketones 3 (8, 27-
Ozonolysis of 1 was carried out in the gas phase at room
temperature at a total pressure of 15.7 Torr and at a partial
pressure of 0.42 Torr for 1 and of 0.35 Torr for ozone. From
the reaction product, we have isolated a 10:1 mixture of the
two diastereomers of ozonide 2, designated 2a and 2b, as
well as ketone 3 and the lactones 4 and 5. GC analysis of the
crude reaction mixture revealed the following product
2
9) and 8 (8) as the predominant organic products. In the
gas-phase ozonolyis of 1, additional organic products have
been assigned structures 13 and 14 by some authors (30, 31),
whereas others described them as “unidentified carbonyl
products” (29) or “neutral” products (27).
The products that we obtained in addition to 3 or 8, viz.,
the ozonides 2 and 7, and the lactones 4, 5, 9, and 10 can
be explained by cleavage of the substrates 1 and 6 to give the
carbonyl oxide intermediates 15 and 16, respectively. In the
ozonolysis of 1 in solution, this direction of cleavage had
indeed been verified by the formation of a cross-ozonide in
the presence of acetaldehyde (20). Reactions of 15 or 16
with formaldehyde afford ozonides 2 and 7, respectively,
while intramolecular Baeyer-Villiger type reactions of 15
and 16 give the corresponding lactones 4 + 5 and 9 + 10,
respectively (Chart 3).
To our knowledge, the present paper describes the first
isolation and subsequent unequivocal structural assignment
of ozonides derived from gas-phase ozonolyses of olefins.
Furthermore, it is the first time that ozonides have been
shown to be formed in the gas-phase ozonolysis of terpenes.
distribution (22): 1% of 2, 55% of 3, 24% of 4, and 20% of
1
5
. In addition, H NMR analysis showed the presence of
small amounts each of formaldehyde (δ ) 9.67), formic acid
δ ) 8.05), and unreacted 1 (δ ) 4.62 and 4.63, dCH ).
Ozonides 2a and 2b have been assigned based on the
(
2
1
identity of the H NMR signals of the CH
CH groups at the ozonide rings (23) with those of the
authentic samples (20) and by reduction of the mixture of
a and 2b with triphenyl phosphine (TPP) to give the expected
3
groups and of the
2
2
ketone 3. Compound 3 was assigned based on the identity
1
of its H NMR data with those of an authentic sample (20),
while 4 (24) and 5 (25) have been assigned based on the
identities of their H NMR data with those published and
1
1
3
additionally based on their C NMR spectra (Chart 1).
Ozonolysis of 6 was carried out in the gas phase at room
temperature at a total pressure of 32.6 Torr and at partial
pressures of 0.88 Torr for 6 and of 0.71 Torr for ozone. From
the reaction product, we have isolated a 2:3 mixture of the
two diastereomers of 7, designated 7a and 7b, as well as
ketone 8 and lactones 9 and 10. The product distribution
Acknowledgments
Support by the Deutsche Forschungsgemeinschaft, the Korea
Science and Engineering Foundation, and the Internationales
Seminar at the University of Karlsruhe is gratefully acknowl-
edged.
(
22) in the crude reaction mixture was 1% of 7, 58% of 8, 13%
1
of 9, and 28% of 10 according to GC analysis. The H NMR
data for the CH groups in the ozonides 7a and 7b were
2
Literature Cited
identical with those of the authentic samples (20), and
reduction of the mixture of 7a and 7b gave ketone 8. The
(
(
1) Atkinson, R. Atmos. Environ. 1990, 24A, 1-141.
2) Niki, H.; Marker, P. D.; Savage, C. M.; Breitenbach, L. P. Chem.
Phys. Lett. 1977, 46, 327-330.
3) Niki, H.; Marker, P. D.; Savage, C. M.; Breitenbach, L. P.; Hurley,
M. D. J. Phys. Chem. 1987, 91, 941-946.
1
H NMR data of 8 were identical with those published (20).
1
Lactone 9 was assigned based on the similarity of its H and
(
1
3
C NMR data with those of respective structural units of the
known lactone 11 (25). Similarly, lactone 10 was assigned
(4) Neeb, P.; Horie, O.; Moortgat, G. K. Tetrahedron Lett. 1996, 37,
9297-9300.
1
13
by analogy of respective H and C NMR data with those of
lactone 12 (26) (Chart 2).
The results obtained in this study differ both from those
obtained in ozonolyses of 1 and 6 in solution (20)swhich
gave predominantly the corresponding ozonides 2 and 7sand
(
5) Fajgar, R.; Vitek, J.; Haas, Y.; Pola, J. Tetrahedron Lett. 1996, 37,
391-3394.
6) Grosjean, D. Atmospheric Chemistry of Biogenic Hydrocarbons,
Am. Chem. Soc. Prepr. Pap. 1994, 34 (1), 691-731.
3
(
(7) Graedel, T. E. Rev. Geophys. Space Phys. 1979, 17, 937-947.
6
4 8
9
ENVIRONMENTAL SCIENCE & TECHNOLOGY / VOL. 32, NO. 5, 1998

(
(
8) Hakola, H.; Arey, J.; Aschmann, S. M.; Atkinson, R. J. Atmos.
Chem. 1994, 18, 75-102.
9) Atkinson, R.; Aschmann, S. M.; Arey, J.; Shorees, B. J. Geophys.
Res. [Atmos.] 1992, 97 (D5), 6065-6073.
(23) The signals of the other structural units of 2a and of 2b
overlapped.
(
(
24) Thomas, A. F.; Rey, F. Tetrahedron 1992, 48, 1927-1942.
25) Parziale, P. A.; Berson, J. A. J. Am. Chem. Soc. 1991, 113, 4595-
(
(
10) Hewitt, C. N.; Kok, G. L. J. Atmos. Chem. 1991, 12, 181-194.
11) Simonaitis, R.; Olszyna, K. J.; Meagher, J. F. Geophys. Res. Lett.
4606.
1
991, 18, 9-12.
12) Kotzias, D.; Fytianos, K.; Geiss, F. Atmos. Environ. 1990, 24A,
127-2132.
13) Atkinson, R.; Hasegawa, D.; Aschmann, S. M. Int. J. Chem. Kinet.
990, 22, 871-887.
(
26) Doyle, M. P.; Winchester, W. R.; Hoorn, J. A. A.; Lynch, V.;
(
(
Simonsen, S. H.; Ghosh, R. J. Am. Chem. Soc. 1993, 115, 9968-
2
9
978.
(
27) Yokouchi, Y.; Ambe, Y. Atmos. Environ. 1985, 19, 1271-1276.
1
(
(
14) Yokouchi, Y.; Ambe, Y. Atmos. Environ. 1985, 19, 1271-1276.
15) Arora, P. K.; Chatha, J. P. S.; Vohra, K. G. Chem. Phys. Lett. 1983,
(28) Hatakeyama, S.; Izumi, K.; Fukuyama, T.; Akimoto, H. J. Geophys.
Res. 1989, 94, 13013-13024.
1
00, 93-98.
(
29) Grosjean, D.; Williams, E. L.; Grosjean, E.; Andina, J. M.; Seinfeld,
(
(
(
(
(
(
(
16) Gaeb, S.; Turner, W. K.; Wolff, S.; Becker, K. H.; Ruppert, L.;
Brockmann, K. J. Atmos. Environ. 1995, 29, 2401-2407.
17) Hatakeyama, S.; Izumi, K.; Fukuyama, T.; Akimoto, H. J. Geophys.
Res., D, Atmos. 1989, 94, 13013-13024.
J. H. Environ. Sci. Technol. 1993, 27, 2754-2758.
(30) Palen, E. J.; Allen, D. T.; Pandis, S. N.; Panken, S. E.; Seinfeld,
J. H.; Flagan, R. C. Atmos. Environ. 1992, 26A, 1239-1251.
18) Atkinson, R.; Winer, A. M.; Pitts, J. N. Atmos. Environ. 1982, 16,
(
31) Jay, K.; Stieglitz, L. Identifizierung chemischer photochemischer
Umsetzungsprodukte von biogenen Kohlenwasserstoffen mit
anthropogenen Luftschadstoffen; Report KfK.-PEF 53;
Kerforschungszentrum: Karlsruhe, 1989; 123 pp.
1
017-1020.
19) Atkinson, R.; Aschmann, S. M.; Arey, J. Atmos. Environ. 1990,
4A, 2647-2654.
20) Griesbaum, K.; Hilss, M.; Bosch, J. Tetrahedron 1996, 52, 14813-
4826.
21) In ref 20, we had erroneously reported the data obtained in
2
1
Received for review July 3, 1997. Revised manuscript received
November 18, 1997. Accepted November 25, 1997.
6 6
C D .
22) Formaldehyde and formic acid are not included in the material
balance.
ES970602R
VOL. 32, NO. 5, 1998 / ENVIRONMENTAL SCIENCE & TECHNOLOGY
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