Synthesis of deuterated 5-n-alkylresorcinols

Article abstract of DOI:10.1002/jlcr.1463

Four alternative strategies for the preparation of deuterium poly-labelled 5-n-alkylresorcinois are explored. Ring-labelled ²H ₃-alkylresorcinols synthesized by acidic H/D exchange are stable under electrospray ionization MS conditio

Full text of DOI:10.1002/jlcr.1463

Research Article
Received 7 July 2007,
Revised 16 August 2007,
Accepted 22 August 2007
Published online 9 January 2008 in Wiley Interscience
(www.interscience.wiley.com) DOI: 10.1002/jlcr.1463
Synthesis of deuterated 5-n-alkylresorcinols
Ã
¨ ¨ ¨
Kirsti Parikka and Kristiina Wahala
Four alternative strategies for the preparation of deuterium poly-labelled 5-n-alkylresorcinols are explored. Ring-labelled
2H3-alkylresorcinols synthesized by acidic H/D exchange are stable under electrospray ionization MS conditions but
scrambling occurs in electron bombardment ionization MS. Side chain-labelled H4-derivatives prepared by two different
2
total synthesis approaches are contaminated by isotopologues with varying number of deuterium labels due to H/D
redistribution and exchange during D2 gas deuterogenation. The derivative carrying an x-2H3 label is isotopically pure and
completely stable under all relevant analytical conditions encountered in quantitation work.
Keywords: 5-n-alkylresorcinols; phenolic lipids; deuterium labelling; stable isotope
found that microwave (MW)-assisted reactions provide an
efficient entry to these products, using DCl or CF3COOD and
Introduction
5-Alk(en)ylresorcinols are non-isoprenoid phenolic lipids that
carry an n-alkyl or alkenyl side chain at C-5 of the resorcinol ring.
They are present in various families of plants (e.g. Gramineae and
Anacardiaceae) and in some families of bacteria.1 The use of 5-n-
alkylresorcinols 1 (Figure 1) as biomarkers of whole grain intake
and of a healthy diet is of great potential due to their presence in
significant amounts in whole grain rye and wheat containing
foods (from 300 mg/kg in whole wheat to 3000 mg/kg in whole
rye).2 5-Alkylresorcinols have various biological effects including
antioxidant activity,3 antimutagenic activity,4 antibacterial prop-
erties5 and inhibition of enzymes,6 for example.
The preparation of an isotopically labelled long chain 5-n-
alkylresorcinol has been described only twice. 14C-heneicosylresor-
cinol (C21) was synthesized for a metabolism study7 and 13C-
dodecylresorcinol (C12) was obtained by biosynthesis starting from a
13C-labelled substrate.8 Two studies concern the labelling of short
alkyl chain (C5, C3) analogues which are substructures of tetrahy-
drocannabinols and their metabolites.9 The quantitative and
qualitative screening of 5-n-alkylresorcinols from biological fluids
has been performed using an even-chain analogue of alkylresorci-
nols as an internal standard,2,10 even though such even-chain
alkylresorcinols have been detected from grains.11 Deuterium-
labelled 5-n-alkylresorcinol analogues with varying alkyl chain
lengths would give a possibility to account more reliably for the
losses during sample preparation in various quantitative measure-
ment procedures.
short reaction times. The mass spectra of the products 2 were
run using electrospray ionization (ESI) due to scrambling
problems12 when electron bombardment ionization (EI) was
used. These compounds, with a 3 amu increase in M1 compared
with the unlabelled analogue (Figure 2) to avoid peak overlap,
should be useful as standards in LC-MS based analytical studies
for example. High-performance liquid chromatography (HPLC)
has been used in the analysis of 5-n-alkylresorcinols, but the
validation procedures appear to be incomplete.2a
To avoid scrambling problems and ensure the stability of the
labels in the various analytical and pretreatment operations that
sample preparation may require, for example, incubating under
acidic conditions or derivatization, we next studied the
introduction of four deuterium labels into the alkyl chain at
the benzylic (a) position and the b site (Scheme 2). The four D
atoms were introduced in a stepwise manner, involving the use
of C-1 deuterated aldehyde (ArCDO) and C-1 dideuterated
primary alcohol (RCD2OH) starting materials and catalytic C = C
2
reduction using D2 gas. The H2-species 7 was homogenous by
MS and NMR, but the product of the reduction (2H4-
nonadecylresorcinol dimethyl ether 8) was contaminated by
some 2H3-nonadecylresorcinol (up to 30%) and by a lesser
amount of 2H2-nonadecylresorcinol (up to 10%) according to the
mass spectra (EI, ESI). Thus, it appeared that D/H scrambling
occurred in the C = C reduction. Earlier, the exchange and
redistribution of hydrogen and deuterium have been observed
when simple alkenes were deuterogenated over a nickel catalyst
giving a mixture of alkanes with varying deuterium content,
We present here the synthesis of 2H3- or 2H4-labelled
alkylresorcinols, aiming at single isotopomers of high
isotopic purity and chemically stable labels. We have investi-
gated different labelling strategies including acid-catalysed
hydrogen/deuterium exchange (Scheme 1) or total synthesis
(Schemes 2, 4, 5 and 6) where the labels are introduced into
different parts of an alkylresorcinol structure.
2
with the H4-derivative as the main product.13
Laboratory of Organic Chemistry, Department of Chemistry, University of
Helsinki, P. O. Box 55, FIN-00014, Finland
Results and discussion
¨
¨ ¨
*Correspondence to: Kristiina Wahala, Laboratory of Organic Chemistry,
Department of Chemistry, University of Helsinki, P. O. Box 55, FIN-00014,
Finland.
2
Acid-catalysed exchange experiments gave the H3-alkylresorci-
nols 2a–d in good yields and isotopic purity (Scheme 1). We
E-mail: Kristiina.Wahala@helsinki.fi
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K. Parikka and K. Wahala
2
mixture of 2H0 up to H15 isotopologues, 2H4- and 2H5-
derivatives being the main products according to MS. There
were no differences between the products of the two catalysts.
Apparently, linoleic acid with the methylene skipped diene
structure is much more prone to scrambling and redistribution
reaction than the styrene derivative 7.
Two variations of another strategy based on the deuterogena-
tion of an alkyne to alkane were studied next (Schemes 4 and 5).
However, D/H scrambling also occurred in the reduction of the
acetylenic starting materials by D2 gas. Deuterium atoms were
introduced not only to the acetylenic carbons but also elsewhere
in the alkyl chain, resulting in a mixture of isotopologous
products (of 13 and subsequent synthetic intermediates 14–16)
according to MS and NMR. In the final alkylresorcinol derivative
17, the 2H4 species was the main product (ca. 29%) but 2H2-, 2H3-
Figure 1. 5-n-alkylresorcinols present in whole grain products. n 5 14/16/18/20/22.
2
and at least H5-2H7-derivatives were present (approximately 11,
20, 20, 12 and 7%, respectively). In the case of 20 the distribution
of the products was different and the heavier species were more
abundant compared with 17. The 2H3-, 2H4-, 2H5- and 2H6-
derivatives were the main constituents in 20 (18, 20, 20 and 19%,
respectively). The H/D exchange and redistribution have not been
reported to occur to a major degree when alkynes are reduced
selectively to alkenes,14 suggesting that the scrambling in our
case occurs at the subsequent alkene reduction stage. However
in our experiments, there was a difference between the products
of the deuterogenation of either alkenes or alkynes. In contrast
with the product 8 (and 9) with only 2H2- and 2H3-derivatives
present in addition to 2H4, in the products 17 (and 13–16) and 20
there were clearly significant amounts of 2H5- and 2H6-derivatives
in the mixture. It seems that controlling the heterogeneous
catalytic D2 reduction of any olefinic or acetylenic starting
material is problematic and specifically deuterated alkylresorci-
nols, or any long alkyl chain species for that matter, cannot be
synthesized in this way.
Scheme 1
Finally, placing D atoms at the remote end of the alkyl chain
in completely unactivating surroundings makes available
derivatives (25, Scheme 6) that are not vulnerable to any kind
of D/H exchanges whatsoever either in solution or in the mass
spectrometer. A 5-(o-methoxycarbonylalkyl)resorcinol dimethyl
ether 21y may be converted in four steps to o-2H3-alkylresorci-
nol with an isotopic purity in excess of 95% (Scheme 3). In the
first step, two D atoms are introduced by LiAlD4 reduction of the
ester. The derived tosylate is very conveniently reduced by
NaBD4 in dimethyl sulphoxide (DMSO) in 8 min under MW
irradiation (cf. the previously reported 2 h required for the
preparation of alkanes with conventional heating15).
Experimental
General
MW-assisted acid-catalysed deuterations were performed in a Teflon
tube with a thread stopper in a domestic MW oven. The reaction
with NaBD4 was performed in a CEM Discovers system. DCl (37% in
D2O), LiAlD4 (99% D) and NaBD4 (99% D) were purchased from
Aldrich. CF3COOD was prepared according to the literature.16
Figure 2. Molecular ion region in the mass spectra (M1H, ESI) of pentadecylre-
sorcinol 1a and D3-pentadecylresorcinol 2a.
Deuterated 3,5-dimethoxybenzaldehyde
3 was prepared as
described in the literature.17 The NMR spectra of the synthesized
compounds were obtained with a Varian 200 or 300 MHz spectro-
meter using tetramethylsilane as an internal standard. Mass spectra
Another alkene reduction strategy was investigated (Scheme
3). The deuterogenation of linoleic acid 10 (over Pd/C or Pd/
BaSO4), a potential starting material for alkylresorcinols, did not
furnish the 2H4-stearic acid 11 cleanly but gave instead a yParikka K and Wa¨ha¨la¨ K, unpublished work.
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K. Parikka and K. Wahala
Scheme 2
natively, 5-pentadecylresorcinol (0.07g, 0.2 mmol) and freshly
prepared CF3COOD (2.5 ml) were MW irradiated in a similar Teflon
tube for 5 min. The procedure was then repeated two times. Each
time the tube was allowed to cool down and 2.5 ml of CF3COOD
was added to replace the acid evaporated into the oven
(CAUTION). The mixture was poured into water (50 ml) and the
product extracted with EtOAc (3ꢀ 15 ml). Recrystallization from
cyclohexane gave [2,4,6-2H3]-5-pentadecylresorcinol (0.062g,
1
89%), m.p. 891C. H NMR (200 MHz, D6-acetone) d 0.86–0.96 (m,
3H, CH3), 1.20–1.35 (m, 14H, CH2), 1.54–1.58 (m, 2H, CH2), 2.45 (t,
2H, J 5 7.7 Hz, CH2Ar), 8.04 (br s, 2H, OH); MS (ESI) m/z (%) 323 (10),
324 (100) [M1H]1, 325 (20).
Scheme 3
were obtained with a JEOL JMS SX102 mass spectrometer operating
at 70 eV (EI), Varian Saturn 2000 instrument (GC-MS, EI), or with a
Mariner ESI TOF (ESI) mass spectrometer. Flash chromatography was
performed with silica gel 60.
[2,4,6-2H3]-5-Heptadecylresorcinol 2b
The reaction was performed as described for 5-pentadecylre-
sorcinol. Recrystallization from cyclohexane gave [2,4,6-2H3]-5-
heptadecylresorcinol (85%), m.p. 911C. 1H NMR (200 MHz, D6-
acetone) d 0.86–0.96 (m, 3H, CH3), 1.20–1.35 (m, 18H, CH2),
1.54–1.58 (m, 2H, CH2), 2.45 (t, 2H, J 5 7.7 Hz, CH2Ar), 8.00 (br s,
[2,4,6-2H3]-5-Pentadecylresorcinol 2a
5-Pentadecylresorcinol (0.1 g, 0.3 mmol) and DCl (2 ml) were MW 2H, OH); MS (ESI) m/z (%) 351 (12), 352 (100) [M1H]1, 353 (30).
irradiated in a Teflon tube, stopper slightly open, for 3 min. The
procedure was then repeated two times. Each time the tube was
[2,4,6-2H3]Nonadecylresorcinol 2c
allowed to cool down and 1.5 ml of DCl was added to replace
the acid partly evaporated into the oven (CAUTION). The mixture
was poured into water (50ml) and the product extracted with
EtOAc (3 ꢀ 15 ml). Recrystallization from cyclohexane afforded
[2,4,6-2H3]-5-pentadecylresorcinol (0.091 g, 91%), m.p. 891C. Alter-
The reaction was performed as described for 5-pentadecylre-
sorcinol. Recrystallization from cyclohexane gave [2,4,6-2H3]
5-nonadecylresorcinol (87%), m.p. 921C. 1H NMR (200 MHz,
D6-acetone) d 0.86–0.96 (m, 3H, CH3), 1.20–1.35 (m, 22H, CH2),
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K. Parikka and K. Wahala
Scheme 4
[1,1-2H2]-1-Bromooctadecane 5
Concentrated HBr (45 ml), H2SO4 (3 ml) and 1,1-D2-1-octadecanol
4 (0.45 g, 1.7 mmol) were refluxed for 4 h. Water was added and
the product extracted with EtOAc (3 ꢀ 20 ml). The combined
extracts were washed with saturated NaHCO3. Evaporation gave
5 as a pale brown powder, which was used in the next step
without purification (0.44 g, 79%). 1H NMR (200 MHz, CDCl3) d
0.84–0.91 (m, 3H, CH3), 1.15–1.36 (m, 30H, CH2), 1.80-1.88 (m, 2H,
CH2); MS (EI, 70 eV) m/z (%) 71 (100), 85 (75), 137 (97), 139 (90),
151 (30), 153 (30), 255 (15), 334 (5), 336 (5).
[1,1-2H2]Octadecyltriphenylphosphonium bromide 6
[1,1-2H2]-1-Bromooctadecane 5 (0.43 g, 1.3 mmol) and PPh3
(0.4 g, 1.5 mmol) were refluxed in dry toluene (10 ml) under
argon for 22 h at 1301C. The solution was allowed to cool down
and evaporated. The product 6 was crystallized from Et2O as a
white powder (0.64 g, 84%), m.p. 961C. 1H NMR (200 MHz, CDCl3)
d 0.80–0.85 (m, 3H, CH3), 1.17–1.35 (m, 30H, CH2), 1.50–1.60 (m,
2H, CH2), 7.65–7.99 (m, 15H, ArH).
Scheme 5
1.53–1.58 (m, 2H, CH2), 2.45 (t, 2H, J 5 7.7 Hz, CH2Ar), 8.00 (br s,
2H, OH); MS (ESI) m/z (%) 379 (10), 380 (100) [M1H]1, 381 (40).
[2,4,6-2H3]-5-Heneicosylresorcinol 2d
[1,2-2H2]-1-(3,5-Dimethoxyphenyl)-1-nonadecene 7
The reaction was performed as described for 5-pentadecylre-
sorcinol. Recrystallization from cyclohexane gave [2,4,6-2H3]-5-
heneicosylresorcinol (90%), m.p. 971C. 1H NMR (200 MHz, D6-
acetone) d 0.86–0.96 (m, 3H, CH3), 1.20–1.35 (m, 26H, CH2),
1.53–1.58 (m, 2H, CH2), 2.45 (t, 2H, J 5 7.7 Hz, CH2Ar), 8.00 (br s,
2H, OH); MS (ESI) m/z (%) 407 (12), 408 (100) [M1H]1, 409 (40).
The phosphonium salt 6 (0.2 g, 0.34 mmol) was stirred with n-
BuLi (0.43 ml, 1.2 M solution in hexane) in THF (10 ml) for 10 min
at 01C. 2H1-3,5-Dimethoxybenzaldehyde 3 (0.056 g, 0.34 mmol)
was added and the solution refluxed overnight. Water was
added and the product extracted with Et2O (3 ꢀ 20 ml).
Combined extracts were washed with brine and dried over
Na2SO4. The product was purified by flash chromatography
eluting with hexane/CH2Cl2 2/3 to give a colourless oil (0.092 g,
67%), a mixture of E/Z isomers (E/Z c.a. 60/40 according to GC-
[1,1-2H2]-1-Octadecanol 4
1
Octadecanoic acid (0.7 g, 2.3 mmol) and LiAlD4 (0.37 g, 8.8 mmol)
were refluxed in dry THF overnight. Water was added and the
product extracted with EtOAc (3 ꢀ 20 ml). Combined extracts
were washed with brine and dried over Na2SO4. Evaporation
gave 4 as a white powder which was used in the next step
without purification (0.49 g, 72%). 1H NMR (200 MHz, CDCl3) d
0.85–0.91 (m, 3H, CH3), 1.15–1.36 (m, 30H, CH2), 1.52–1.58 (m,
2H, CH2); MS (EI, 70 eV) m/z (%) 97 (100), 111 (70), 125 (30), 140
(20), 226 (15), 254 (30) [MꢁH2O]1.
MS and H NMR). MS (EI, 70 eV) m/z (%) 152 (30), 153 (100), 179
(20), 403 (10), 404 (65) M1, 405 (20).
[1,1,2,2-2H4]-1-(3,5-Dimethoxyphenyl)nonadecane 8
[1,2-2H2]-1-(3,5-Dimethoxyphenyl)-1-nonadecene
7
(0.025 g,
0.06 mmol) was stirred in CH2Cl2 containing 0.005 g of Pd/C
(10% w/w) and connected to a balloon containing deuterium
gas. The mixture was stirred overnight at room temperature.
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¨ ¨ ¨
K. Parikka and K. Wahala
Scheme 6
Filtration of the reaction mixture through Celites gave 8 as a (10 ml) at 721C for 1 h. 1-Bromotetradecane (0.6 g, 2.2 mmol) was
mixture of isotopologues (2H2, 10%, 2H3, 30%, 2H4, 60%, 0.022 g, added and the solution was stirred at room temperature
90%). 1H NMR (200 MHz, CDCl3) d 0.85–0.91 (m, 3H, CH3), overnight. The solution was acidified with 0.1 M HCl and
1.13–1.38 (m, 30H, CH2), 3.78 (s, 6H, OMe), 6.29 (t, 1H, J 5 2.2 Hz, extracted with Et2O (3 ꢀ 30 ml). The combined extracts were
H-40), 6.34 (d, 2H, J 5 2.2 Hz, H-20 and H-60); MS (EI, 70 eV) m/z (%) dried over MgSO4. Flash chromatography on silica gel eluting
153 (70), 154 (100), 406 (10), 407 (25), 408 (50) M1, 409 (20).
with hexane/acetone 1/1 gave 12 (0.41 g, 52%) as an amorphous
solid. 1H NMR (200 MHz, CDCl3) d 0.83–0.90 (m, 3H, CH3),
1.12–1.38 (m, 22H, CH2), 1.40–1.55 (m, 2H, CH2), 2.10–2.18 (m,
2H, H-5), 2.37–2.46 (m, 2H, H-2), 3.66 (t, 2H, J 5 6.2 Hz, H-1); 13C
NMR (200 MHz, CDCl3) d 15.4, 20.0, 24.0, 24.5, 30.2, 30.3, 30.5,
30.6, 30.8, 31.0, 33.2, 62.7, 77.5, 84.1; MS (EI, 70 eV) m/z (%) 55
(100), 69 (97), 84 (100), 97 (100), 107 (73), 109 (67), 121 (50), 135
(30), 153 (30), 223 (20), 237 (10), 265 (8), 266 (15).
[1,1,2,2-2H4]-1-(3,5-Dihydroxyphenyl)nonadecane 9
[1,1,2,2-2H4]-1-(3,5-Dimethoxyphenyl)nonadecane
8
(0.02 g,
0.05 mmol) was stirred with BBr3 (0.44 ml, 1 M solution in
CH2Cl2) in CH2Cl2 (5 ml) under argon at 01C until the reaction
was complete according to TLC. Water was added and the
product extracted with EtOAc (3 ꢀ 10 ml). The combined
extracts were washed with saturated NaHCO3 and dried over
Na2SO4. Flash chromatography on silica gel eluting with MeOH/
EtOAc/CH2Cl2 1/2/7 gave 9 as a mixture of isotopologues (2H2,
Deuterated octadecanol 13
3-Octadecyn-1-ol 12 (0.14 g, 0.53 mmol) was stirred in CH2Cl2
containing 0.015 g of Pd/C (10% w/w) and connected to a
balloon containing deuterium gas. The mixture was stirred
overnight at room temperature. Filtration of the reaction
mixture through Celites gave a mixture of isotopologues
(2H2-2H7, 2H3-2H5 as the main products, 0.13 g, 93%). 1H NMR
(200 MHz, CDCl3) d 0.84–0.90 (m, 3H, CH3), 1.12–1.37 (m, ca. 26H,
CH2), 1.50–1.56 (m, 2H, CH2), 3.62 (t, 2H, J 5 6.6 Hz, H-1).
2
2
1
10%, H3, 40%, H4, 50%, 0.015 g, 79%). H NMR (200 MHz, D6-
acetone) d 0.86–0.96 (m, 3H, CH3), 1.20–1.35 (m, 30H, CH2), 6.18
(s, 3H, H-20, H-40 and H-60), 8.14 (s, 2H, OH); MS (EI, 70 eV) m/z (%)
125 (65), 126 (100), 378 (7), 379 (25), 380 (37) M1, 381 (10).
Deuteration of linoleic acid
Linoleic acid (0.5g, 1.8 mmol) was stirred in CH2Cl2 containing
0.05 g of Pd/C (10% w/w) and connected to a balloon containing
deuterium gas. The mixture was stirred overnight at room
temperature. Filtration of the reaction mixture through Celites
gave a mixture of deuterated stearic acids (2H0-2H15, 2H4 and 2H5
the main isotopologues) (0.51 g, 98%). A similar mixture (2H0-2H15)
was obtained using Pd/BaSO4 (0.1 g, 5% w/w) instead of Pd/C
Deuterated bromooctadecane 14
Concentrated HBr (15 ml), H2SO4 (1 ml) and 13 (0.092 g,
0.34 mmol) were refluxed for 4 h. Water was added and the
product extracted with EtOAc (3 ꢀ 20 ml). The combined
extracts were washed with saturated NaHCO3. Evaporation gave
14 as a pale yellowish powder, which was used in the next step
without purification (isotopologues 2H2-2H7, 2H3-2H5 as the main
products, 0.087 g, 77%). 1H NMR (200 MHz, CDCl3) d 0.85–0.91
(m, 3H, CH3), 1.13–1.38 (m, ca. 26H, CH2), 1.79–1.89 (m, 2H, CH2),
3.40 (t, 2H, J 5 6.6 Hz, H-1).
1
(0.51 g, 99%). H NMR (200MHz, CDCl3) d 0.85–0.91 (m, 3H, CH3),
1.15–1.40 (m, c.a. 24H, CH2), 1.60–1.67 (m, 2H, CH2), 2.34 (t, 2H,
J 5 7.2 Hz, H-2); MS (EI, 70eV) m/z (%) 97 (25), 98 (40), 99 (25), 115
(30), 116 (20), 129 (90), 130 (40), 131 (17), 284 (10), 285 (27), 286
(60), 287 (80), 288 (92), 289 (92), 290 (85), 291 (75), 292 (65), 293
(55), 294 (47), 295 (40), 296 (33), 297 (25), 298 (20), 299 (15).
3-Octadecyn-1-ol 12
Deuterated octadecyltriphenylphosphonium bromide 15
3-Butyn-1-ol (0.3 g, 0.0043 mmol), HMPA (2.3 g, 12.9 mmol, Deuterated bromooctadecane 14 (0.087 g, 0.26 mmol) and PPh3
2.3 ml) and n-BuLi (1.2 M in hexane, 7.2 ml) were stirred in THF (0.074 g, 0.29 mmol) were refluxed in dry toluene (5 ml) under
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K. Parikka and K. Wahala
argon for 20 h at 1301C. The solution was allowed to cool down 107.2, 144.9, 161.3; MS (EI, 70 eV) m/z (%) 152 (100), 191 (25), 203
and evaporated. The product was crystallized from Et2O as a (10), 217 (12), 259 (7), 274 (5) M1.
white powder (isotopologues 2H2-2H7, 2H3-2H5 as the main
products, 0.11 g, 71%). 1H NMR (200 MHz, CDCl3) d 0.82–0.87 (m, Deuterogenation of 19
3H, CH3), 1.18–1.36 (m, ca. 26H, CH2), 1.56–1.66 (m, 2H, CH2),
1-(3,5-Dimethoxyphenyl)-4-decyne (19) (0.024g, 0.087 mmol) was
3.66–3.86 (m, 2H, H-1), 7.54–7.88 (m, 15H, ArH).
stirred in CH2Cl2 containing 0.003 g of Pd/C (10% w/w) and
connected to a balloon containing deuterium gas. The mixture
was stirred overnight at room temperature. Filtration of the
Deuterated 1-(3,5-dimethoxyphenyl)-1-nonadecene 16
reaction mixture through Celites gave 20 (isotopologues 2H3,
The phosphonium salt 15 (0.10 g, 0.17 mmol) was stirred with n-
18%; 2H4, 20%; 2H5, 20%; 2H6, 19% as the main products; 0.023 g,
BuLi (0.15 ml, 1.2 M solution in hexane) in THF (10 ml) for 10 min
95%). MS (EI, 70eV) m/z (%) 151 (10), 152 (90), 153 (100), 154 (60),
under argon at 01C. 3,5-Dimethoxybenzaldehyde (0.028 g,
155 (20), 281 (11), 282 (14), 283 (13), 284 (13), 285 (9), 286 (6).
0.17 mmol) was added and the solution refluxed overnight.
Water was added and the product extracted with Et2O
[1,1-2H2]-12-(3,5-Dimethoxyphenyl)dodecan-1-ol 22
(3 ꢀ 20 ml). Combined extracts were washed with brine and
dried over Na2SO4. The product was purified by flash
Methyl 12-(3,5-dimethoxyphenyl)dodecanoate 21 (0.075 g,
chromatography eluting with hexane/CH2Cl2 2/3 to give a
0.21 mmol) and LiAlD4 (0.040 g, 0.84 mmol) were refluxed in
2
2
2
2
colourless oil (isotopologues H2, 10%; H3, 21%; H4, 31%; H5,
13%; 2H6, 17%; 2H7, 6%; 0.045 g, 65%). MS (EI, 70 eV) m/z (%) 151
(20), 152 (100), 153 (50), 154 (20), 179 (25), 404 (15), 405 (35), 406
(50), 407 (35), 408 (25), 409 (15).
dry THF for 3 h. Water was added and the mixture was acidified
with 0.1 M HCl. The product was extracted with EtOAc
(3 ꢀ 10 ml). Combined extracts were washed with brine and
dried over Na2SO4. Evaporation gave 22 as a white powder
which was used in the next step without purification (0.070 g,
93%). 1H NMR (300 MHz, CDCl3) d 1.26–1.35 (m, 16H, CH2),
1.53–1.60 (m, 4H, CH2), 2.54 (t, 2H, J 5 7.6 Hz, CH2Ar), 3.78 (s, 6H,
OMe), 6.29 (t, 1H, J 5 2.1 Hz, H-40), 6.34 (d, 2H, J 5 2.1 Hz, H-20
and H-60); 13C NMR (300 MHz, CDCl3) d 25.7, 29.3, 29.4, 29.6, 31.3,
31.8, 32.6, 36.3, 55.2, 97.6, 106.5, 145.4, 160.7.
Deuterated 1-(3,5-dimethoxyphenyl)nonadecane 17
The nonadecene 16 (0.01 g, 0.025 mmol) was hydrogenated by
H2 gas in CH2Cl2 containing 0.001 g of Pd/C (10% w/w) under
atmospheric pressure and room temperature. Filtration of the
reaction mixture through Celites gave 17 (isotopologues 2H2,
2
2
2
2
2
11%; H3, 20%; H4, 29%; H5, 20%; H6, 12%; H7, 7%; 0.009 g,
89%). MS (EI, 70 eV) m/z (%) 151 (20), 152 (100), 153 (60), 154
(25), 406 (12), 407 (25), 408 (30), 409 (25), 410 (20), 411 (10).
[1,1-2H2]-12-(3,5-Dimethoxyphenyl)dodecyl toluenesulpho-
nate 23
[1,1-2H2]-12-(3,5-Dimethoxyphenyl)dodecan-1-ol 22 (0.06 g,
0.18 mmol), toluenesulphonyl chloride (0.041 g, 0.22 mmol) and
Et3N (0.04 ml) were stirred in CH2Cl2 (5 ml) at room temperature
overnight. Water was added and the product extracted with
CH2Cl2 (3 ꢀ 10 ml). Combined extracts were washed with brine
and dried over Na2SO4. Flash chromatography on silica gel
1-Decen-4-yne 18
1-Heptyne (0.50 g, 0.52 mmol, 0.68 ml), n-BuLi (4.2 ml, 1.25 M
solution in hexane) and THF (7 ml) were stirred at ꢁ721C under
argon for 1 h. 1-Bromopropene (0.63 g, 0.52 mmol, 0.44 ml) was
added and the solution stirred at room temperature overnight.
Water was added and the product extracted with hexane
(2 ꢀ 30 ml). The combined extracts were dried over MgSO4.
Distillation under reduced pressure gave 18 as a colourless oil
(0.3 g, 43%), b.p. 72–731C/22 mmHg (Lit. 73–741C/22 mmHg18).
1H NMR (200 MHz, CDCl3) d 0.85–0.93 (m, 3H, CH3), 1.31–1.55 (m,
6H, CH2), 2.10–2.25 (m, 2H, H-6), 2.90–2.97 (m, 2H, H-3), 5.05–5.15
(m, 1H, H-1), 5.25–5.35 (m, 1H, H-1), 5.75–5.95 (m, 1H, H-2).
1
eluting with CH2Cl2 gave 23 (0.053 g, 62%). H NMR (300 MHz,
CDCl3) d 1.21–1.29 (m, 16H, CH2), 1.53–1.64 (m, 4H, CH2), 2.44 (s,
3H, CH3), 2.54 (t, 2H, J 5 7.6 Hz, CH2Ar), 3.78 (s, 6H, OMe), 6.29 (t,
1H, J 5 2.1 Hz, H-40), 6.34 (d, 2H, J 5 2.1 Hz, H-20 and H-60), 7.34
(d, 2H, J 5 8.0 Hz, ArH), 7.79 (d, 2H, J 5 8.0 Hz, ArH); 13C NMR
(300 MHz, CDCl3) d 21.6, 25.3, 28.6, 28.9, 29.4, 29.5, 31.3,
36.3, 55.2, 97.6, 106.5, 127.9, 129.8, 145.4, 160.7; MS (EI, 70 eV)
m/z (%) 91 (45), 151 (45), 152 (100), 194 (10), 306 (10), 478 (20)
M1, 479 (5).
1-(3,5-dimethoxyphenyl)-4-decyne 19
1-Decen-4-yne 18 (0.05 g, 0.37 mmol), 9-BBN (1.5 ml, 0.5 M
solution in THF) and dry THF (11 ml) were stirred under argon
[12,12,12-2H3]-1-(3,5-Dimethoxyphenyl)dodecane 24
at room temperature for 2.5 h. NaOMe (0.046 g, 0.86 mmol), [1,1-2H2]-12-(3,5-Dimethoxyphenyl)dodecyl toluenesulphonate
PdCl2 (dppf) (0.016 g, 0.02 mmol) and 3,5-dimethoxyphenol 23 (0.050 g, 0.1 mmol) and NaBD4 (0.009 g, 0.21 mmol) were
trifluoromethanesulfphonate (0.19 g, 0.66 mmol) were added stirred under MW irradiation (100 W, 851C) for 8 min in DMSO
and the mixture refluxed for 2 h. Water was added and the (2 ml). Water was added and the product extracted with Et2O
product extracted with Et2O (3 ꢀ 20 ml). The combined extracts (3 ꢀ 10 m). The combined extracts were dried over Na2SO4. Flash
were washed with brine and dried over Na2SO4. The product chromatography on silica gel eluting with CH2Cl2 gave 24
was purified by flash chromatography eluting with CH2Cl2/ (0.019 g, 63%). 1H NMR (300 MHz, CDCl3) d 1.26–1.31 (m, 18H,
hexane 2/1 to give a colourless oil (0.024 g, 24%). 1H NMR CH2), 1.53–1.64 (m, 2H, CH2), 2.54 (t, 2H, J 5 7.8 Hz, CH2Ar), 3.78
(200 MHz, CDCl3) d 0.88–0.94 (m, 3H, CH3), 1.34–1.57 (m, 6H, (s, 6H, OMe), 6.30 (t, 1H, J 5 2.1 Hz, H-40), 6.35 (d, 2H, J 5 2.1 Hz,
CH2), 1.75–1.85 (m, 2H, CH2), 2.14–2.20 (m, 4H, CH2), 2.66 (t, 2H, H-20 and H-60); 13C NMR (300 MHz, CDCl3) d 13.9, 22.4, 29.4, 29.5,
J 5 7.6 Hz, CH2Ar), 3.78 (s, 6H, OCH3), 6.30 (t, 1H, J 5 2.2 Hz, H-4), 29.7, 31.3, 31.9, 36.3, 55.2, 97.6, 106.5, 145.5, 160.7; MS (EI, 70 eV)
6.36 (d, 2H, J 5 2.2 Hz, H-2 and H-6); 13C NMR (200 MHz, CDCl3) d m/z (%) 121 (10), 151 (55), 152 (100), 165 (40), 194 (10), 308 (5),
14.6, 18.9, 19.3, 22.8, 29.5, 31.1, 31.7, 35.7, 55.8, 80.2, 81.5, 98.4, 309 (30) M1, 310 (5).
J. Label Compd. Radiopharm 2008, 51 12–18
Copyright r 2008 John Wiley & Sons, Ltd.
www.jlcr.org

¨ ¨ ¨
K. Parikka and K. Wahala
[12,12,12-2H3]-1-(3,5-Dihydroxyphenyl)dodecane 25
References
[12,12,12-2H3]1-(3,5-Dimethoxyphenyl)dodecane 24 (0.016 g,
0.05 mmol) was stirred with BBr3 (0.21 ml, 1 M solution in
CH2Cl2) in CH2Cl2 (5 ml) under argon at 01C until the reaction
was complete according to TLC. Water was added and the
product extracted with EtOAc (3 ꢀ 10 ml). The combined
extracts were washed with saturated NaHCO3 and dried over
Na2SO4. Flash chromatography on silica gel eluting with MeOH/
CH2Cl2 1/9 gave 25 (0.012 g, 80%). 1H NMR (300 MHz, D6-
acetone) d 1.20–1.35 (m, 18H, CH2), 1.54–1.58 (m, 2H, CH2), 2.44
(t, 2H, J 5 7.6 Hz, CH2Ar), 6.18 (s, 3H, H-20, H-40 and H-60), 7.96 (s,
2H, OH); 13C NMR (300 MHz, D6-acetone) d 13.7, 23.0, 29–30
(overlapping with acetone), 32.0, 32.5, 36.5, 100.9, 107.6, 145.7,
159.2; MS (EI, 70 eV): m/z (%) 88 (30), 123 (30), 124 (100), 138 (60),
149 (10), 280 (3), 281 (20) M1, 282 (5).
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Jenny and Antti Wihuri Foundation, the Academy of Finland
(205781) and the Graduate School of Bio-organic and Medicinal
Chemistry are gratefully acknowledged for partial financial support.
www.jlcr.org
Copyright r 2008 John Wiley & Sons, Ltd.
J. Label Compd. Radiopharm 2008, 51 12–18