Design, synthesis and photoactivation studies of fluorous photolabels

Article abstract of DOI:10.1039/c1ob05748k

Two fluorous diazirine photolabels were designed, synthesized and subjected to photoactivation studies. The photoactivation studies revealed an unexpected photoreaction when the fluorous tag was directly connected to the diazirine ring, leading to the formation of a fluorous alkene. The more efficient photolabel of the two was identified as a flexible precursor for target specific photoaffinity labels for fluorous proteomics by adding appropriate ligands depending on the target protein subset. As a proof of feasibility, mannose residues were added to the photolabel making it a potential photoaffinity label to tag proteins that bind mannose.

Full text of DOI:10.1039/c1ob05748k

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PAPER
Design, synthesis and photoactivation studies of fluorous photolabels†
Arun Babu Kumar, Jordan Micheal Anderson and Roman Manetsch*
Received 12th May 2011, Accepted 13th June 2011
DOI: 10.1039/c1ob05748k
Two fluorous diazirine photolabels were designed, synthesized and subjected to photoactivation studies.
The photoactivation studies revealed an unexpected photoreaction when the fluorous tag was directly
connected to the diazirine ring, leading to the formation of a fluorous alkene. The more efficient
photolabel of the two was identified as a flexible precursor for target specific photoaffinity labels for
fluorous proteomics by adding appropriate ligands depending on the target protein subset. As a proof
of feasibility, mannose residues were added to the photolabel making it a potential photoaffinity label
to tag proteins that bind mannose.
been limited research in the development of fluorous photoaffinity
Introduction
probes. Song and Zhang reported the synthesis of the first class of
In proteomics, fractionation techniques are widely applied and
fluorous photolabeling agents, in which the photoreactive diazirine
ring is incorporated on the fluorous tag (Fig. 1).15 Meanwhile,
Burkard and coworkers reported the design and synthesis of
fluorinated photoaffinity probe attached to V-ATPase inhibitors.16
Although these previous works showed the efficiency of fluorous
probe–fluorous stationary phase interaction, its use in protein
labeling experiments has not been reported thus far.
usually involve an affinity-based enrichment step prior to
mass spectrometry analysis. Biotin is one of the most com-
mon affinity tags taking advantage of the very strong biotin–
streptavidin interaction.1 Immobilized metal ion affinity chro-
matography (IMAC),2 lectin affinity chromatography3 and en-
richment of an alkyne-tagged proteome via the Huisgen 1,3-
dipolar cycloaddition4 are alternative affinity-based separations
which have recently found broad use. Nevertheless, there is a dire
need for additional fractionation techniques complementing the
current ones that suffer from shortcomings such as impermeability,
incomplete elution from affinity column5 and complication of
MS/MS spectral interpretation due to undesired fragmentation
of the affinity tag.6
Fig. 1 Previously reported fluorous photolabel.15
Fluorous tags have emerged as
a useful purification
tool in catalysis,7 combinatorial chemistry,8 natural product
synthesis,9,10 microarrays,11 peptide labeling, peptide purification
and proteomics.12,13 Fluorous tags are commercially available,
relatively inexpensive, highly inert to most reaction conditions
and do not complicate MS/MS spectral interpretation due to
their stability against fragmentation in the mass spectrometer.13
Recently, the concept of fluorous proteomics has been introduced
since fluorous tags have proven to be an effective enrichment
moiety for peptides, proteins and small molecules of biological
origin.11–14
Herein, we describe the design and synthesis of two diazirine-
containing fluorous photolabels, 1 and 2 (Fig. 2). Photolabel 1,
which is closely related to the previously reported photolabel,15
consists of a diazirine ring directly installed in the fluorous tag,
while in probe 2, the diazirine ring and the fluorous tag are apart
from each other.
Photoaffinity labeling has been a valuable biochemical tool
for studying the interaction between a ligand and its receptor.
Although there has been significant success in the use of fluorous
tags in the enrichment of peptides12,13 and proteins,11 there has
Fig. 2 Design of fluorous photolabels 1 and 2.
Department of Chemistry, University of South Florida, CHE205, 4202
East Fowler Ave, Tampa, Florida, USA, 33620. E-mail: manetsch@usf.edu;
Fax: +1-813-974-3203; Tel: +1-813-974-7306
† Electronic supplementary information (ESI) available: General infor-
mation, experimental procedures and spectral characterization of all
compounds. See DOI: 10.1039/c1ob05748k
Furthermore, we report photoactivation studies of diazirines 1
and 2. These studies demonstrate that fluorous probe 1 unexpect-
edly eliminates to form a fluorous alkene as the major product
when the fluorous chain is directly connected to the diazirine ring.
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These results suggest that probe 1 or a fluorinated photoaffinity
probe design similar to the probe developed by Song and Zhang
probably leads to deactivation upon UV irradiation, rendering it
unavailable to tag the protein. In contrast, photolabel 2 with its
fluorous tag remote from the diazirine ring undergoes photoac-
tivation cleanly to the desired product. Therefore, photolabel 2
can serve as a flexible precursor for the synthesis of fluorous and
target-specific photoaffinity labels by attaching suitable ligands to
the benzyl alcohol groups. As proof of principle, the synthesis and
characterization of potential target-specific, mannose-containing
photolabel 3 is discussed.
8 with ammonia failed. The bulky nature of the two TBS groups
and the fluorous tag in 8 could be the possible reason for the
unexpected failure. Thus a synthetic route was devised involving
a TBS deprotection prior to the diaziridine ring formation. The
tosyloxime 8 was treated with HF for TBS deprotection. Then,
the cyclization step with ammonia yielded the desired diaziridine,
which was oxidized using iodine to give the diazirine 1 in 49% yield
over three steps.
The synthesis of photolabel 2 began with the preparation of aryl
iodide 9 through the diazo intermediate derived from dimethyl 5-
aminoisophthalate. The aryl iodide 9 was subjected to Miyaura
borylation followed by hydrolysis to give the boronic acid 10
(Scheme 2). In parallel, 3-bromo-5-iodobenzoic acid was refluxed
with diphenyl phosphoryl azide (DPPA) and triethylamine to
generate the corresponding aryl isocyanate, which underwent
Curtius rearrangement with t-butyl alcohol to give the Boc-
protected amine 11. The boronic acid 10 was coupled with the
iodide 11 via Suzuki cross-coupling reaction, followed by Boc
deprotection under acidic condition to give amine 12 in good
yield over two steps. Amine 12 was converted to its corresponding
arenediazonium salt using sodium nitrite and HBF4, which was
followed by Heck coupling of the arenediazonium salt with
(perfluorohexyl)ethylene to give the alkene 13.17
Results and discussion
Design of fluorous photolabels
In photoaffinity labeling, a ligand linked to a photoreactive group
is bound non-covalently to a specific receptor in the proteome.
Upon exposure to light, a covalent bond is formed between the
photoreactive group and the receptor. The labeled protein is then
separated from the unlabeled proteins using the affinity tag that the
photolabel is equipped with. Analogously, the design of fluorous
photolabels 1 and 2 includes the integration of three essential
moieties in one molecule (Fig. 2): (a) alcohol functions for the
attachment of ligands that specifically bind to the receptor of
interest in a proteome mixture, (b) a diazirine ring for the photo-
induced covalent cross linking between the photolabel and its
receptors and (c) a fluorous tag for the straightforward isolation of
the photolabeled targets from the proteome mixture. Two alcohol
residues were incorporated in photolabels 1 and 2 to induct avidity
effect by covalent attachment of two ligands.
Synthesis of photolabels
For the synthesis of photolabel 1 (Scheme 1), diol 4 was protected
as its tert-butyldimethyl silyl (TBS) ether 5. Lithiation of 5 by
n-butyllithium followed by the addition of methyl perfluoro-
heptanoate gave ketone 6 in moderate yield. Ketone 6 was
converted to the corresponding oxime 7 and subsequently to-
sylated to the tosyl oxime 8 in good yield. The attempts to
form the diaziridine via direct nucleophilic attack of tosyloxime
Scheme 2 Synthesis of alkene 13.
The next crucial step was the selective reduction of the electron-
deficient carbon–carbon double bond of the aryl bromide 13
via catalytic hydrogenation. Alkenyl-substituted aryl bromides
undergo debromination under the widely used hydrogenation
conditions of hydrogen and palladium on charcoal (Pd/C).
Catalytic hydrogenation of perfluorinated alkenyl-aryl bromides
to the corresponding saturated aryl bromides has been previously
reported to succeed with rhodium on charcoal (Rh/C) only
at high hydrogen pressure of 50 bar.17 Alternatively, alkenyl-
substituted aryl bromides have been reported to be hydrogenated
with Adam’s catalyst (Pt2O).18 However, previous attempts to
reduce perfluorinated alkenes under similar reaction conditions
failed due to the electron-deficient double bond.17 After exploring
a number of reaction conditions, Pt2O in ethyl acetate at 40
psi (2.75 bar) hydrogen pressure was found to provide the
Scheme 1 Synthesis of photolabel 1.
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Scheme 3 Synthesis of photolabel 2.
maximal yield of 14. Other combinations of solvent and hydrogen
pressures resulted in the formation of debrominated product or the
unreacted alkene. This catalytic hydrogenation is an interesting
find due to the aforementioned importance of the molecules
with fluorous tags and aryl-bromide residues that help in further
derivatization. Using these optimized reaction conditions, alkene
13 was hydrogenated to the diester 14 in 83% yield. Diester
14 was subjected to LAH reduction and the resulting diol was
protected as the TBS ether 15 in good yield. Compound 15 was
reacted with n-butyllithium followed by methyl trifluoroacetate
to furnish ketone 16 in moderate yield. Treatment of ketone 16
with hydroxylamine hydrochloride and sodium acetate followed
by tosylation furnished tosyl oxime 17 in moderate yield. The tosyl
oxime 17 was cyclized with liquid ammonia to the diaziridine 18 in
good yield. Oxidation of the diaziridine 18 using AgO followed by
TBS deprotection yielded the desired photolabel 2 in good yield
(Scheme 3).
19. 19F-NMR and LCMS (Fig. 4, A—right and B—bottom) of the
final sample indicated that ether 19 was the only major product.
Further purification and analysis of the photo irradiated final
sample confirmed the formation of one single product 19. The
photoactivation of photolabel 1, which has structural similarity
with the work reported by Song and Zhang,15 was investigated
next (Scheme 4). Close observation of the chemical shift of the
trifluoromethyl group in 19F-NMR (Fig. 4, A—left) over the course
of the photoreaction suggested the decomposition of photolabel
1 into multiple products. HPLC analysis (Fig. 4, B—top) of the
photoirradiated sample identified three distinct peaks. The two
most abundant photoproducts were isolated by reverse phase
HPLC and subjected to HRMS. The mass of one of the minor
products matched the predicted photoactivation product, ether
21. However, the major product had a mass corresponding to a
molecular formula of C16H9D3F12O3, which led to the conclusion
that it was 21 - DF. Further characterization using 1D and 2D
NMR (19F-gCOSY, 19F-NOESY, Fig. 5) indicated that the major
photoactivation product with the mass equal to 21 - DF is the
polyfluorinated alkene 22. In recent literature, a combination of
19F-gCOSY and 19F-NOESY has proved to be an efficient method
for structural analysis of perfluorinated straight chains.21 19F-
Photoactivation studies of photolabels 1 and 2
The photoactivation reactions were conducted in deuterated
methanol with UV light irradiation (l > 320 nm) and the
reactions were monitored by 19F-NMR at various time intervals.
As expected from previous studies,19,20 upon irradiation, diazirine
2 cleanly reacted within 5 min to methyl ether 19 and linear
diazo compound 20 (Fig. 3). On further exposure to UV light,
the linear diazo compound 20 was converted to the methyl ether
4
gCOSY shows the JFF correlations where as 19F-NOESY shows
4
3
both JFF and JFF correlations. By using these two techniques
in tandem, sequencing of straight chain fluorous tag is made
straightforward and reliable. As shown in Fig. 5, 19F-NOESY
4
3
of 22 gives JFF and JFF correlations while19F-gCOSY shows
4
only the JFF correlations except for the vinyl fluorine due to its
connection to a sp2 carbon.21 The third minor photoproduct was
not characterized due to its very low availability.
It has been suggested that photoaffinity labeling is highly
dependent on the generation of a reactive intermediate ideally
undergoing clean insertion reactions. If the lifetime of the reactive
intermediate is too long and the ligand–protein exchange rate is
high, then the photolabel dissociates from the binding site and
possibly attaches to parts of the protein other than the binding
site or even other proteins, resulting in an unspecific labeling
also termed pseudo-affinity labeling.22 In order to avoid pseudo-
affinity labeling, the photochemically generated intermediate
should be highly reactive, very short lived and not susceptible to
intramolecular rearrangements to much less reactive species.22 The
unexpected outcome of the photoreaction of probe 1 suggests that
the predicted carbene-insertion reaction is not the major pathway
and thus probe 1 has potential for pseudoaffinity labeling.23 These
Fig. 3 Formation of 19 and 20 from 2 during the course of photoactiva-
tion in relative percent distribution, as estimated by 19F-NMR.
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Fig. 4 (A) 19F NMR (zoomed at CF3 signal of fluorous tag) of 1 (left) and 2 (right) at different time intervals of UV irradiation (B) HPLC trace of 1
(top) and 2 (bottom) before (left) and after (right) UV irradiation.
Scheme 4 Photoactivation pattern of the photolabel 1 and 2.
using mannose ligands. To achieve glycosylation of the diol 2
with a glycosyl-donor like mannose pentaacetate, it is essential to
use boron trifluoride etherate to activate the glycosyl donor. The
glycosylation reaction yielded the desired bis-glycosylated product
with the intact diazirine ring as the major product. Subsequently,
the crude material was subjected to acetate deprotection using
sodium methoxide and purified by preparative HPLC to obtain
Fig. 5 The correlations observed with 19F-gCOSY and 19F-NOESY of
photoproduct 22.
the desired fluorous photolabel 3 in moderate yield over two
steps (Scheme 5). The coupling constants and 2D NMR indicated
that the bis-glycosylation was diastereoselective, yielding the a-
anomer exclusively. The alcohols in the photolabel can be further
converted to amine and carboxylic acid groups as reported by Song
and Zhang,15 for efficient attachment of various ligands targeting
different receptors.
results clearly distinguish compound 1 from the conventional
trifluoromethyldiazirine probe 2.
Synthesis of mannose photoaffinity probe 3
The photoactivation studies suggest that photolabeling agent 1
and the previously reported photolabels (Fig. 1), in which the
diazirine ring is directly incorporated on the fluorous chain, would
possibly lead to poor and/or nonspecific protein labeling and
consequently to erroneous or misleading data interpretations.
Therefore, for deriving target specific photoaffinity probes, it is
essential to use a predictable photolabel like 2. Since proteins that
bind to mannose residues occupy a central role in glycobiology,24
we decided to assess the derivatization capacity of photolabel 2
Enrichment of photoaffinity probe 3 by FSPE
To evaluate the enriching ability of the photolabel using fluorous
interactions a mixture of peptide along with the photolabel 3 was
loaded on to a bed of fluorous silica gel in a pipette column
(fluorous bed: 40 ¥ 6 mm) (Fig. 6). Initially the loaded fluorous
short column was flushed with water to elute out the peptide
(Fig. 6, B) and followed by elution with methanol to get the
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directly incorporated in the fluorous tag, mainly undergoes a self-
deactivating elimination to yield a polyfluorinated alkene. This
potential self-deactivation of the transient carbene suggests that
photoprobe 1 is not ideal for specific photolabeling of protein or
proteome samples. Conversely, photolabel 2 was found to be a
reliable photolabel for derivatization with target specific ligands.
As a proof of feasibility to derivatize photolabel 2, mannose-
containing photoaffinity probe 3 was synthesized and its efficacy
in fluorous enrichment was evaluated. On the route to synthesize
photolabel 2, we have optimized an efficient and low hydrogen
pressure method to hydrogenate a carbon-carbon double bond on
a perfluorinated alkenyl-aryl bromide.
Scheme 5 Synthesis of fluorous photoaffinity label 3.
Experimental section
General information
All NMR experiments were performed on a Varian Inova
400 MHz spectrometer (1H at 400, 13C at 100 and 19F at 376 MHz).
Chemical shifts (in ppm, d scale) are reported using solvent peak
as internal standard. The ESI high resolution mass spectra were
recorded using Agilent G1969A mass detector with time-of-flight
(TOF) analyzer. Thin layer chromatography was performed on
EMD silica gel 60-F plates and the spots were visualized with
UV light or iodine stain. Purification of reaction crude was done
by flash chromatography using EMD silica gel (230–400 mesh).
The elemental analysis were carried out at Atlantic Microlab,
Inc., Georgia. The melting points of compounds were measured
on Electrothermal Mel-Temp 3.0. The photoactivation studies
were done using Orel Instruments housing with Osram 150 W
XBO xenon short-arc lamp. The light source was fitted with a
Schott filter WG-320 to eliminate UV lights below 320 nm. The
photoactivation studies were done as reported by Brunner and
Richards.19
(5-Bromo-1,3-phenylene)bis(methylene)bis(oxy)bis(tert-butyldi-
methylsilane) (5). To a solution of (5-bromo-1,3-phenylene)-
dimethanol25 4 (1.21 g, 5.57 mmol) in dry dichloromethane
(35 mL), TBSCl (2.10 g, 13.9 mmol) and imidazole (1.13 g,
16.6 mmol) were added and stirred at room temperature for 16 h.
The reaction mixture was quenched with sat. ammonium chloride
solution and extracted with dichloromethane. The organic layer
was dried over anhydrous sodium sulfate and concentrated. The
resulting crude was purified by silica column chromatography
(19 : 1, hexanes and ethyl acetate) to give 5 (2.33 g, 94%) as
a colorless oil. Rf 0.72 (19 : 1 hexanes and ethyl acetate). dH
(400 MHz; CDCl3) 7.32 (2H, s), 7.19 (1H, s), 4.70 (4H, s), 0.93
(18H, s), 0.09 (12H, s). dC (100 MHz; CDCl3) 143.8, 127.7, 122.5,
122.3, 64.5, 26.1, 18.6, -5.0. Elemental analysis (CHN) calculated
for C20H37BrO2Si2 (%) C, 53.9; H, 8.4; N, 0.0; found C, 54.15; H,
8.4; N, 0.0.
Fig. 6 Separation of fluorous photolabel 3 from unlabeled peptide using
fluorous silica gel: HPLC trace of (A) mixture of peptide and photolabel 3
(B) fraction eluted by 100% water (C) fraction eluted by 100% methanol.
fluorous photolabel 3 (Fig. 6, C). These data show the potency
of fluorous separation just by using a short plug of fluorous
silica gel. Further it has already been demonstrated that short
fluorous tags can be used for the efficient enrichment of peptides
and proteins using fluorous derivatized silica gel or fluorous
derivatized glass plates.12,13,11 These previous reports coupled
with the aforementioned enrichment data show that 3 and the
derivatives of 2, with different ligands, can prove to be efficient
enrichment moieties in specific photolabeling of macromolecules
of biological origin.
1-(3,5-Bis((tert-butyldimethylsilyloxy)methyl)phenyl)-2,2,3,3,4,
4,5,5,6,6,7,7,7-tridecafluoroheptan-1-one (6). To a solution of
5 (1.94 g, 4.35 mmol) in dry diethyl ether (30 mL) under
argon, n-butyllithium (4.35 mL of 2.5 M soln in hexane) was
added dropwise at -40 ◦C. The reaction mixture was warmed
to 10 ◦C and stirred for 2 h, then cooled back to -50 ◦C
and methyl perfluoroheptanoate (6.57 g, 17.4 mmol) was added
dropwise. The solution was warmed to room temperature and
Conclusions
Wehave designedandsynthesized two multifunctionalphotolabels
1 and 2. Photoactivation studies with labeling agents 1 and
2 revealed that photolabel 1, in which the diazirine ring is
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stirred for 4 h. Later the reaction mixture was quenched with
saturated ammonium chloride solution and extracted with ether.
The organic layer was dried over anhydrous sodium sulfate and
concentrated. The resulting crude was purified by silica column
chromatography (100% hexanes) to yield 6 (1.76 g, 57%) as a
colorless oil. dH (400 MHz; CDCl3) 7.91 (2H, s), 7.62 (1H, s), 4.79
(4H, s), 0.94 (18H, s), 0.11 (12H, s). dC (100 MHz; CDCl3) 183.6
(t, J = 25.8 Hz), 142.9, 130.6, 128.3, 126.5, 120.9–104.9 (m), 64.4,
26.1, 18.6, -5.2. dF (376 MHz; CDCl3) -81.3 (3F), -113.1 (2F),
-121.3 (2F), -121.6 (2F), -123.2 (2F), -126.6 (2F).
sulfate and concentrated under vacuum. This crude was dissolved
in methanol (1.5 mL) and triethylamine (60 mg) was added
to it, followed by the dropwise addition of iodine solution in
methanol (30 mg mL-1) until the color of iodine persisted. The
reaction proceeded for another 30 min and the solvent was
evaporated, followed by the addition of water and extraction
with ethyl acetate. The organic layer was dried over anhydrous
sodium sulfate, concentrated and the resulting crude was purified
using silica column chromatography (97 : 3, dichloromethane and
methanol) to give 1 (18.9 mg, 49%) as a white solid. Rf 0.51 (23 : 2,
dichloromethane and methanol). Mp: 69–70 ◦C. dH (400 MHz;
CD3OD) 7.43 (1H, s), 7.33 (2H, s), 4.85 (2H, s), 4.61 (4H, s). dC
(100 MHz; CD3OD) 144.9, 130.4, 128.3, 126.3, 119.6–109.0 (m),
64.5, 29.1 (t, J = 28.6 Hz). dF (376 MHz; CD3OD) -82.85 (3F),
-110.95 (2F), -121.50 (2F), -123.39 (2F), -124.28 (2F), -127.77
(2F). HRMS (ESI+) for [M + Na]+; calculated: 519.03487, found:
519.03391 (error = -1.84 ppm).
1-(3,5-Bis((tert-butyldimethylsilyloxy)methyl)phenyl)-2,2,3,3,4,
4,5,5,6,6,7,7,7-tridecafluoroheptan-1-one oxime (7). A suspen-
sion of hydroxylamine HCl (0.687 g, 9.88 mmol) and sodium
acetate trihydrate (2.02 g, 14.8 mmol) in ethanol (7.5 mL) was
stirred for 15 min and allowed to settle. The supernatant from this
mixture was added dropwise to a solution of 6 (1.76 g, 2.47 mmol)
in ethanol (7.5 mL) and refluxed for 16 h. The reaction was cooled
and solvent was evaporated under vacuum. The resulting residue
was extracted with ether, washed with water and concentrated after
drying the organic layer over anhydrous sodium sulfate. The crude
was purified by silica column chromatography (19 : 1, hexanes and
ethyl acetate) to give 7 (0.788 g, 44%) as a colorless oil. Rf 0.36
(9 : 1, hexanes and ethyl acetate). dH (400 MHz; CDCl3) 9.53 (1H,
s), 7.38 (1H, s), 7.22 (2H, s), 4.77 (4H, s), 0.93 (18H, s), 0.09 (12H,
s). dC (100 MHz; CDCl3) 149.0 (t, J = 24.7 Hz), 141.9, 126.8, 125.9,
125.4, 118.8–108.1 (m), 64.9, 26.0, 18.6, -5.1.
tert-Butyl 3-bromo-5-iodophenylcarbamate (11). To a solution
of 3-bromo-5-iodobenzoic acid (5.0 g, 15.3 mmol) in t-butanol
(25 mL), triethylamine (2.01 g, 19.9 mmol) and diphenylphos-
phorylazide (4.63 g, 16.8 mmol) were added and refluxed for
24 h under argon. The reaction mixture was concentrated under
vacuum, extracted with diethyl ether, and washed with 10% NaOH
solution, water (2 times) and then brine solution. After drying over
anhydrous sodium sulfate, the organic layer was concentrated and
the crude was purified using silica column chromatography (9 : 1,
hexanes and ethyl acetate) to give 11 (4.57 g, 75%) as a white
solid. Rf 0.72 (4 : 1, hexanes and ethyl acetate). Mp: 97–98 ◦C. dH
(400 MHz; CDCl3) 7.65 (1H, s), 7.54 (1H, s), 7.48 (1H, s), 6.44
(1H, s), 1.49 (9H, s). dC (100 MHz; CDCl3) 152.2, 140.7, 134.2,
125.8, 123.2, 120.8, 94.3, 81.7, 28.5. HRMS (ESI+) for [M + H]+;
calculated: 397.92471, found: 397.92424 (error = -1.17 ppm).
1-(3,5-Bis((tert-butyldimethylsilyloxy)methyl)phenyl)-2,2,3,3,4,
4,5,5,6,6,7,7,7-tridecafluoroheptan-1-one O-tosyl oxime (8). To
a solution of 7 (0.207 g, 0.28 mmol) in dichloromethane
(0.5 mL), diisopropylethylamine (44.1 mg, 0.34 mmol) and 4-
dimethylaminopyridine (2.6 mg, 21 mmol) were added under
argon. The reaction mixture was cooled to 0 ◦C and tosyl chloride
(65 mg, 0.34 mmol) was added in small portions. The solution
was warmed to room temperature and stirred for 40 min and
the reaction mixture was quenched with water and extracted
with dichloromethane. After being dried over anhydrous sodium
sulfate, the organic layer was concentrated. The resulting crude
was purified using silica column chromatography (19 : 1, hexanes
and ethyl acetate) to give 8 (0.210 g, 84%) as a colorless oil. Rf
0.65 (9 : 1, hexanes and ethyl acetate). dH (400 MHz; CDCl3) 7.84
(2H, d, J = 8.3 Hz), 7.40 (1H, s), 7.35 (2H, d, J = 8.3 Hz), 7.10
(2H, s), 4.75 (4H, s), 2.45 (3H, s), 0.92 (18H, s), 0.09 (12H, s).
dC (100 MHz; CDCl3) 155.9 (t, J = 26.2 Hz), 146.2, 142.6, 131.6,
129.9, 129.5, 126.5, 125.0, 124.5, 118.8–105.7 (m), 64.5, 26.1, 21.8,
18.5, -5.1.
Dimethyl 3¢-amino-5¢-bromobiphenyl-3,5-dicarboxylate (12).
To an argon back-flushed flask, tetrahydrofuran (150 mL), 2 M
sodium carbonate solution (45 mL), 10 (10.95 g, 46.0 mmol),
11 (11.5 g, 28.8 mmol) and bis(triphenylphosphine)palladium(II)
dichloride (1.01 g, 1.44 mmol) were added and refluxed for
24 h. The reaction mixture was cooled, extracted with ethyl
acetate and washed with water. The organic layer was dried
with anhydrous sodium sulfate and concentrated. The resulting
crude was dissolved in dichloromethane (60 mL) followed by
the addition of trifluoroacetic acid (20 mL) and stirred for an
hour. The reaction mixture was concentrated and purified by silica
column chromatography (7 : 3, hexanes and ethyl acetate) to give
the product 12 (5.97 g, 57%). Rf 0.37 (4 : 1, hexanes and ethyl
acetate). Mp: 195–197 ◦C dH (400 MHz; CD3OD) 8.59 (1H, t, J =
1.4 Hz), 8.38 (2H, d, J = 1.5 Hz), 7.03 (1H, t, J = 1.5 Hz), 6.93 (1H,
t, J = 1.6 Hz), 6.90 (1H, t, J = 1.7 Hz), 3.98 (6H, s). dC (100 MHz;
CD3OD) 167.55, 151.93, 142.95, 142.84, 133.03, 132.74, 130.46,
124.72, 119.49, 118.35, 113.23, 53.18. HRMS (ESI+) for [M +Na]+;
calculated: 385.99984, found: 385.99896 (error = -2.29 ppm).
(5-(3-(Perfluorohexyl)-3H-diazirin-3-yl)-1,3-phenylene)dimetha-
nol (1). To a solution of 8 (68 mg, 77.1 mmol) in acetonitrile,
50% aqueous solution of HF (0.3 mL) was added slowly and
stirred for 4 h. The reaction was quenched with saturated
sodium bicarbonate solution, extracted with ethyl acetate and
concentrated after drying over anhydrous sodium sulfate. The
crude was dissolved in dry ether (1 mL) under argon and cooled
to -50 ◦C. Ammonia (around 2 mL) was condensed in the cooled
flask and left to stir at this temperature for 8 h. Ammonia was
evaporated by warming the reaction mixture to room temperature
followed by the addition of water and extraction with ethyl
acetate. The organic layer was dried with anhydrous sodium
Dimethyl 3¢-bromo-5¢-(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooct-
1-enyl)biphenyl-3,5-dicarboxylate (13). To a 50% aqueous solu-
tion of tetrafluoroboric acid (70 mL) and water (70 mL) at 0 ◦C,
12 (5.97 g, 16.4 mmol) was added. A solution of sodium nitrite
(1.69 g, 24.6 mmol) in water (10 mL) was added dropwise to the
reaction mixture over 10 min and warmed to room temperature.
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After 16 h the reaction mixture was filtered and washed with
5% tetrafluoroboric acid followed by diethyl ether. Upon drying
the residue under argon, it was suspended in degassed methanol
(160 mL) followed by the addition of palladium(II) acetate (55 mg,
245 mmol) and perfluorohexylethylene (7.94 g, 22.9 mmol). The
was dried over anhydrous sodium sulfate and concentrated under
vacuum. The resulting crude was purified using silica column
chromatography (97 : 3, hexanes and ethyl acetate) to yield 15 (1.38
g, 86%) as a colorless oil. Rf 0.68 (19 : 1, hexanes and ethyl acetate).
d
H (400 MHz; CDCl3) 7.61 (1H, s), 7.37 (2H, s), 7.34 (1H, s), 7.33
◦
suspension was warmed to 40 C and stirred until gas evolution
(2H, s), 4.80 (4H, s), 3.06–2.84 (2H, m), 2.55–2.27 (2H, m), 0.96
(18H, s), 0.12 (12H, s). dC (100 MHz; CDCl3) 144.2, 142.5, 141.8,
139.4, 130.2, 128.9, 126.1, 123.7, 123.6, 123.3, 121.6–107.0 (m),
65.1, 33.1 (t, J = 22.2 Hz), 25.3–27.5 (m), 18.7, -5.1. dF (376 MHz;
CDCl3) -81.24 (3F), -115.03 (2F), -122.29 (2F), -123.29 (2F),
-123.89 (2F), -126.58 (2F).
ceased and then stirred for an additional 30 min. The reaction
mixture was concentrated, extracted with ether and washed with
water followed by drying the organic layer over anhydrous sodium
sulfate and concentration under vacuum. The crude was purified
using silica column chromatography (17 : 3, hexanes and ethyl
acetate) to give the product 13 as a white solid (7.7 g, 68%). Rf 0.53
(4 : 1, hexanes and ethyl acetate). mp: 156–157 ◦C. dH (400 MHz;
CDCl3) 8.68 (1H, s), 8.39 (2H, s), 7.77 (1H, s), 7.65 (1H, s), 7.60
(1H, s), 7.17 (1H, d, J = 16.0 Hz), 6.36–6.22 (1H, m), 3.97 (6H, s).
dC (100 MHz; CDCl3) 166.1, 142.0, 139.9, 138.20 (t, J = 9.3 Hz),
136.3, 132.4, 131.9, 131.8, 130.5, 130.0, 125.6, 124.0, 123.0–107.3
(m), 117.0 (t, J = 23.3 Hz), 52.8. dF (376 MHz; CDCl3) -81.24 (3F),
-111.85 (2F), -121.99 (2F), -123.27 (2F), -123.44 (2F), -126.56
(2F). Elemental analysis (CHN, F) calculated for C24H14BrF13O4
(%) C, 41.6; H, 2.0; N, 0.0; F, 35.6; found C, 41.9; H, 1.9; N, 0.0;
F, 35.9.
1-(3¢,5¢-Bis((tert-butyldimethylsilyloxy)methyl)-5-(3,3,4,4,5,5,6,
6,7,7,8,8,8-tridecafluorooctyl)biphenyl-3-yl)-2,2,2-trifluoroetha-
none (16). To a solution of 15 (2.64 g, 3.05 mmol) in dry diethyl
ether (13 mL), n-butyllithium (3.0 mL of 2.5 M solution in
hexane, 7.5 mmol) was added dropwise at -50 ◦C under argon
and warmed to 0 ◦C. After 2 h the reaction was cooled back
to -50 ◦C and a solution of methyl trifluoroacetate (975 mg,
7.62 mmol) in dry diethyl ether (1.5 mL) was added dropwise and
stirred for another 3 h. The reaction was quenched with saturated
ammonium chloride solution and extracted with diethyl ether.
The organic layer was dried over anhydrous sodium sulfate and
concentrated under vacuum. The resulting crude was purified
using silica column chromatography (9 : 1, hexanes and ethyl
acetate) to yield 16 (1.69 g, 63%) as a pale yellow oil. Rf 0.57
(17 : 3, hexanes and ethyl acetate). dH (400 MHz; CDCl3) 8.21
(1H, s), 7.92 (1H, s), 7.82 (1H, s), 7.50 (2H, s), 7.37 (1H, s), 4.86
(4H, s), 3.10 (2H, dd, J = 8.3, 6.0 Hz), 2.59–2.40 (2H, m), 0.99
(18H, s), 0.16 (12H, s). dC (100 MHz; CDCl3) 180.63 (q, J =
35.1 Hz), 143.52, 142.88, 141.17, 139.18, 134.35, 131.27, 128.58,
127.56, 123.85, 123.56, 122.31–106.79 (m), 64.99, 32.99 (t, J =
22.1 Hz), 24.5–27.5 (m), 18.65, -5.20. dF (376 MHz; CDCl3)
-71.78 (3F), -81.40 (3F), -114.96 (2F), -122.35 (2F), -123.37
(2F), -123.91 (2F), -126.68 (2F). Elemental analysis (CHN, F)
calculated for C36H44F16O3Si2 (%)C, 48.9; H, 5.0; N, 0.0; F, 34.3;
found C, 49.3; H, 5.1; N, 0.0; F, 34.4.
Dimethyl
3¢-bromo-5¢-(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluoro-
octyl)biphenyl-3,5-dicarboxylate (14). To a solution of 13 (1.59
g, 2.30 mmol) in ethyl acetate (50 mL), platinum oxide (26 mg,
115 mmol) was added and the reaction mixture was shaken in a
hydrogenator under 40 psi of hydrogen gas. After 3 days, another
portion of platinum oxide (26 mg, 115 mmol) was added and the
reaction was shaken under 40 psi for another 3 days and the
reaction mixture was filtered and concentrated. The crude was
purified using silica column chromatography (4 : 1, hexanes and
ethyl acetate) to give the product 14 (1.32 g, 83%) as a◦ white
solid. Rf 0.25 (4 : 1 hexanes and ethyl acetate). mp: 77–80 C. dH
(400 MHz; CDCl3) 8.66 (1H, s), 8.38 (2H, s), 7.66 (1H, s), 7.40
(2H, s), 3.97 (6H, s), 2.96 (2H, dd, J = 10.0, 6.7 Hz), 2.49–2.33
(2H, m). dC (100 MHz; CDCl3) 166.2, 142.2, 141.8, 140.4, 132.4,
131.6, 131.3, 130.2, 128.9, 126.2, 123.7, 121.6–106.5 (m), 52.8,
33.0 (t, J = 22.0 Hz), 26.5. dF (376 MHz; CDCl3) -81.24 (3F),
-114.98 (2F), -122.29 (2F), -123.29 (2F), -123.83 (2F), -126.58
(2F). Elemental analysis: calculated for C24H16BrF13O4 (%) C,
41.5; H, 2.3; Br, 11.5; F, 35.5; O, 9.2; found C, 41.75; H, 2.2; Br,
11.6; F, 35.7; O, 9.5.
1-(3¢,5¢-Bis((tert-butyldimethylsilyloxy)methyl)-5-(3,3,4,4,5,5,6,
6,7,7,8,8,8-tridecafluorooctyl)biphenyl-3-yl)-2,2,2-trifluoroetha-
none O-tosyl oxime (17). A suspension of hydroxylamine HCl
(276 mg, 3.96 mmol) and sodium acetate trihydrate (809 mg,
5.95 mmol) in ethanol (5 mL) was stirred for 15 mins and allowed
to settle. The supernatant from this mixture was added dropwise
to a solution of 16 (1.755 g, 1.98 mmol) in ethanol (6 mL) and
refluxed for 16 h. The solvent was evaporated from the reaction
mixture under vacuum and the residue was extracted with ether
and washed with water. After drying the organic layer over
anhydrous sodium sulfate it was concentrated under vacuum.
The resulting residue was dissolved in dry dichloromethane (6
mL) followed by the addition of DIEA (307 mg, 2.4 mmol), and
DMAP (18 mg, 7.5 mol%) under argon at room temperature.
The reaction mixture was cooled to 0 ◦C and tosyl chloride
(457 mg, 2.4 mmol) was added in small portions, warmed to room
temperature and stirred for 40 min. The reaction was quenched
with saturated ammonium chloride solution and extracted with
dichloromethane followed by drying the organic layer over
anhydrous sodium sulfate and concentration under vacuum. The
resulting crude was purified using silica column chromatography
(49 : 1, hexanes and ethyl acetate) to yield 17 (1.14 g, 55%). Rf
(3¢-Bromo-5¢-(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl)biphe-
nyl-3,5-diyl)bis(methylene)-bis(oxy)bis(tert-butyldimethylsilane)
(15). To a suspension of lithium aluminium hydride (211 mg,
5.56 mmol) in dry tetrahydrofuran (9 mL), a solution of 14 (1.288
g, 1.85 mmol) in dry tetrahydrofuran (11 mL) was added dropwise
at 0 ◦C under argon. Another 4 mL of tetrahydrofuran was added
through the dropping funnel to rinse down the dropping funnel
and warmed to room temperature. After 45 min the reaction
was quenched by slow addition of saturated sodium sulfate
solution and extracted with ethyl acetate followed by drying the
organic layer with anhydrous sodium sulfate and concentrated
under vacuum. To the concentrated residue, dichloromethane (12
mL), TBDMS-Cl (838 mg, 5.56 mmol) and imidazole (757 mg,
11.1 mmol) were added at room temperature and stirred overnight.
The reaction was quenched with saturated ammonium chloride
solution, extracted with dichloromethane and the organic layer
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0.46 (19 : 1 hexanes and ethyl acetate). dH (400 MHz; CDCl3) 7.89
(2H, d, J = 8.0 Hz), 7.58 (1H, s), 7.45–7.32 (6H, m), 7.16 (1H, s),
4.82 (4H, s), 3.16–2.94 (2H, m), 2.62–2.28 (5H, m), 0.97 (18H, s),
0.13 (12H, s). dC (100 MHz; CDCl3) 154.3 (q, J = 33.7 Hz), 146.4,
143.2, 142.7, 140.7, 139.4, 131.4, 130.5, 130.1, 129.5, 127.0, 126.0,
125.4, 123.7, 123.6, 121.7–107.7 (m), 65.0, 32.9 (t, J = 22.3 Hz),
28.72–23.11 (m), 21.9, 18.6, -5.2. dF (376 MHz; CDCl3) -61.93,
-67.41 (3F), -71.71, -81.28 (3F), -114.95 (2F), -122.28 (2F),
-123.29 (2F), -123.84 (2F), -126.59 (2F).
(tetrahydro-2H-pyran-2,3,4,5-tetraol) (3). To a solution of 2
(40 mg, 59.8 mmol) and mannose pentaacetate (70.4 mg, 180
mmol) in anhydrous dichloromethane (0.55 mL), BF3 Et2O (59 mg,
∑
415 mmol) was added at 0 ◦C under argon and stirred for 30
min. The reaction mixture was then warmed to room temperature
and stirred for additional 18 h followed by quenching with water.
The reaction mixture was extracted with dichloromethane and
the organic layer was dried over anhydrous sodium sulfate and
concentrated. The residue was dissolved in anhydrous methanol
(0.4 mL) followed by the addition of 5 M sodium methoxide
solution (40 mL) and stirred at room temperature, under argon, for
3 h. The reaction was quenched with the addition of Amberlyst-15
and filtered. The filtrate was concentrated and the resultant residue
was purified by reverse phase semi-prep HPLC.26 The collected
peaks with the desired compound, as identified by LC-MS, were
concentrated and lyophilized to give 3 (25.6 mg, 43%) as a white
solid. dH (400 MHz; CD3OD) 7.69 (1H, s), 7.53 (2H, s), 7.48 (1H,
s), 7.32 (1H, s), 7.19 (1H, s), 4.88 (2H, d, J = 1.7 Hz), 4.84 (13H, m,
including solvent peak), 4.64 (2H, d, J = 12.0 Hz), 3.91–3.81 (4H,
m), 3.79–3.69 (4H, m), 3.67–3.58 (4H, m), 3.10–3.00 (2H, m),
2.65–2.46 (2H, m). dC (100 MHz; CD3OD) 143.9, 143.1, 141.5,
140.5, 131.2, 130.5, 128.7, 127.5, 126.9, 124.8, 124.2–108.2 (m),
100.9, 75.2, 72.8, 72.3, 69.8, 68.8, 63.1, 33.4 (t, J = 19.2), 29.7 (q,
J = 40.4), 27.5. dF (376 MHz; CD3OD) -67.41 (3F), -82.84 (3F),
-115.74 (2F), -123.33 (2F), -124.31 (2F), -124.74 (2F), -127.75
(2F). HRMS (ESI+) for [M+Na]+; calculated: 1015.1905, found:
3-(3¢,5¢-Bis((tert-butyldimethylsilyloxy)methyl)-5-(3,3,4,4,5,5,6,
6,7,7,8,8,8-tridecafluorooctyl)biphenyl-3-yl)-3-(trifluoromethyl)-
diaziridine (18). To a solution of 17 (1.0 g, 0.948 mmol) in dry
diethyl ether (6 mL), ammonia (10 mL) was condensed at -60 ◦C
and stirred for 8 h. Ammonia was evaporated by warming the
reaction to room temperature and extracted with ether followed
by washing the organic layer with water. The ether layer was dried
over anhydrous sodium sulfate and concentrated under vacuum
followed by purification with silica column chromatography (9 : 1,
hexanes and ethyl acetate) to yield 18 (677 mg, 79%) as a white
solid. Rf 0.32 (9 : 1, hexanes and ethyl acetate). mp: 65–66 ◦C. dH
(400 MHz; CDCl3) 7.75 (1H, s), 7.53 (1H, s), 7.44 (3H, s), 7.33
(1H, s), 4.83 (4H, s), 3.02 (2H, dd, J = 10.0, 6.7 Hz), 2.85 (1H, d,
J = 8.6 Hz), 2.57–2.35 (2H, m), 2.30 (1H, d, J = 8.7 Hz), 0.98 (18H,
s), 0.14 (12H, s). dC (100 MHz; CDCl3) 143.0, 142.6, 140.6, 139.8,
133.1, 129.1, 126.9, 125.7, 123.6, 123.5, 120.0–107.6 (m), 65.0,
58.2 (q, J = 36.0 Hz), 33.1 (t, J = 21.8 Hz), 29.2–23.2 (m), 18.6,
-5.1. dF (376 MHz; CDCl3) -75.88 (3F), -81.35 (3F), -115.05
(2F), -122.34 (2F), -123.33 (2F), -123.90 (2F), -126.65 (2F).
Elemental analysis (CHN, F) calculated for C36H46F16N2O2Si2
(%)C, 48.1; H, 5.2; N, 3.1; F, 33.8; found C, 48.7; H, 5.2; N, 3.0;
F, 33.3.
1
1015.1906 (error = 0.1 ppm). Please refer to ESI† for H-COSY
and HMQC.
(3¢-(3,3,4,4,5,5,6,6,7,7,8,8,8-Tridecafluorooctyl)-5¢-(2,2,2-triflu-
oro-1-[2H3]methoxy[1-2H]ethyl)biphenyl-3,5-diyl)dimethanol (19).
Photolabel 2 (3.6 mg, 5.3 mmol) was dissolved in methanol-D4
(0.6 mL) in a 5 mm NMR tube. This solution was subjected to
photoirradiation with UV light (>320 nm) and the photoactiva-
tion was followed at various time intervals using 19F NMR. After
one hour of UV irradiation the sample was transferred to a 2 mL
vial and subjected to HPLC purification27 and the peak at 20.2 min
was collected and concentrated, followed by lyophilization to give
19. dH (400 MHz; CD3OD) 7.63 (1H, s), 7.61 (1H, s), 7.55 (2H, s),
7.36 (2H, s), 4.69 (4H, s), 3.08–3.01 (2H, m), 2.71–2.42 (2H, m). dF
(376 MHz; CD3OD) -78.59 (3F, s), -82.85 (3F, t), -115.79 (2F, m),
-123.34 (2F, m), -124.32 (2F, m), -124.79 (2F, m), -127.76 (2F,
m). HRMS (ESI+) for [M+NH4]+; calculated: 694.17463, found:
694.17198 (error = -3.82 ppm).
(3¢-(3,3,4,4,5,5,6,6,7,7,8,8,8-Tridecafluorooctyl)-5¢-(3-(trifluo-
romethyl)-3H-diazirin-3-yl)biphenyl-3,5-diyl)dimethanol (2). To
a solution of 18 (0.317 g, 0.353 mmol) in dry diethyl ether
(4.5 mL), AgO (0.655 g, 5.29 mmol) was added and stirred
for 2 h. The reaction mixture was filtered and the residue was
washed with diethyl ether. The filtrate was concentrated and
dissolved in ethanol (6 mL) and pyridine p-toluenesulfonate
(177 mg, 0.706 mmol) was added to it and stirred overnight at
room temperature. After concentrating the reaction mixture under
vacuum it was extracted with ethyl acetate and washed with water.
The organic layer was dried over anhydrous sodium sulfate and
concentrated, followed by silica column chromatography (97 : 3,
dichloromethane and methanol) to give 2 (0.171 g, 72%) as a
white solid. Rf 0.38 (23 : 2, dichloromethane and methanol). Mp:
(5-(2,2,3,3,4,4,5,5,6,6,7,7,7-Tridecafluoro-1-[2H3]methoxy[1-
2H]heptyl)-1,3-phenylene)dimethanol (21). Photolabel 1 (50 mg,
101 mmol) was dissolved in methanol-D4 (5 mL) in a test tube.
This solution was subjected to photoirradiation with UV light
(>320 nm) and the photoactivation was followed at various time
intervals using 19F NMR. After 2 h of UV irradiation the sample
was subjected to HPLC purification27 and the major peak at 14.1
mins was collected and concentrated, followed by lyophilization to
give 21. dH (400 MHz, CD3OD) 7.44 (1H, s), 7.38 (2H, s), 4.85 (4H,
s, including solvent peak), 4.66 (4H, s). dC (101 MHz, CD3OD)
143.7, 133.4, 127.9, 127.5, 64.9. HRMS (ESI+) for [M+NH4]+;
calculated: 522.12464, found: 522.12456 (error = -0.16 ppm).
◦
90–91 C. dH (400 MHz; CDCl3) 7.40 (1H, s), 7.34 (3H, s), 7.17
(1H, s), 7.02 (1H, s), 4.65 (4H, s), 3.39 (2H, s), 2.92 (2H, dd,
J = 9.8, 6.7 Hz), 2.44–2.28 (2H, m). dC (100 MHz; CDCl3) 142.5,
142.3, 141.0, 140.3, 130.6, 128.8, 125.6, 125.2, 125.1, 123.9, 121.7–
107.9 (m) 64.9, 32.9 (t, J = 22.1 Hz), 28.6 (q, J = 40.5 Hz), 26.7.
dF (376 MHz; CDCl3) -65.70 (3F), -81.45 (3F), -115.09 (2F),
-122.43 (2F), -123.42 (2F), -123.93 (2F), -126.73 (2F). HRMS
(ESI+) for [M + NH4]+; calculated: 686.12945, found: 686.12865
(error = -1.18 ppm).
(2S,2¢S,3S,3¢S,4S,4¢S,5S,5¢S,6R,6¢R)-6,6¢-(3¢-(3,3,4,4,5,5,6,6,
7,7,8,8,8-Tridecafluorooctyl)-5¢-(3-(trifluoromethyl)-3H-diazirin-
3-yl)biphenyl-3,5-diyl)bis(methylene)bis(oxy)bis(methylene)bis-
(5-(2,3,3,4,4,5,5,6,6,7,7,7-Dodecafluoro-1-[2H3]methoxyhept-1-
enyl)-1,3-phenylene)dimethanol (22). Photolabel
1 (50 mg,
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101 mmol) was dissolved in methanol-D4 (5 mL) in a test tube.
This solution was subjected to photo irradiation with UV light
(>320 nm) and the photoactivation was followed at various time
intervals using 19F NMR. After 2 h of UV irradiation the sample
was subjected to HPLC purification27 and the major peak at 12.9
min was collected and concentrated, followed by lyophilization to
give 22. dH (400 MHz; CD3OD) 7.50 (1H, s), 7.25 (2H, s), 4.66
(4H, s). dF (376 MHz; CD3OD) -82.90 (3F, t), -112.41 (2F, m),
-123.81 (2F, m), -124.46 (2F, m), -127.86 (2F, m), -157.96 (1F,
m). HRMS (ESI+) for [M+NH4]+; calculated: 501.1121, found:
501.1117 (error = -0.97 ppm). Please refer to ESI† for 19F-COSY
and 19F-NOESY.
9 D. P. Curran and Z. Luo, J. Am. Chem. Soc., 1999, 121, 9069.
10 (a) Z. Luo and D. P. Curran, Science, 2001, 291, 1766; (b) E. R.
Palmacci, M. C. Hewitt and P. H. Seeberger, Angew. Chem., Int. Ed.,
2001, 40, 4433.
11 (a) K.-S. Ko and N. L. Pohl, J. Am. Chem. Soc., 2005, 127, 13162; (b) N.
L. Pohl, Angew. Chem., Int. Ed., 2008, 47, 3868.
12 (a) V. Montanari and K. Kumar, J. Am. Chem. Soc., 2004, 126, 9528;
(b) E. P. Go, E. C. Peters and G. Siuzdak, J. Proteome Res., 2007, 6,
1492.
13 S. M. Brittain and E. C. Peters, Nat. Biotechnol., 2005, 23, 463.
14 W. H. Pearson and D. Sercel Anthony, J. Org. Chem., 2005, 70, 7114.
15 Z. Song and Q. Zhang, Org. Lett., 2009, 11, 4882.
16 N. Burkard, T. Bender, J. Westmeier, C. Nordmann, M. Huss, H.
Wieczorek, S. Grond and P. von Zezschwitz, Eur. J. Org. Chem., 2010,
2176–2181.
17 S. Darses and J.-P. Genet, Eur. J. Org. Chem., 2001, 1121.
18 S. Franks and F. R. Hartley, J. Chem. Soc., Perkin Trans. 1, 1980,
2233.
19 J. Brunner and F. M. Richards, J. Biol. Chem., 1980, 255, 3313.
20 M. Daghish and P. Welzel, Angew. Chem., Int. Ed., 2002, 41, 2293.
21 (a) M. F. Mahon, M. K. Whittlesey and P. T. Wood, Organometallics,
1999, 18, 4068; (b) J. L. Battiste, N. Jing and R. A. Newmark, J. Fluorine
Chem., 2004, 125, 1331; (c) J. L. Battiste and R. A. Newmark, Prog.
Nucl. Magn. Reson. Spectrosc., 2006, 48, 1.
Acknowledgements
We thank the USF FCoE-BITT (GALS007) and the Bankhead-
Coley Cancer Research Program (08BN-04-17195) for funding.
We also thank Dr Edwin Rivera and David Badger from USF
NMR facility for their help with 19F-2D NMR spectroscopy.
22 (a) J. Brunner, Annu. Rev. Biochem., 1993, 62, 483–514; (b) J. Das,
Chem. Rev., ACS ASAP, DOI: 10.1021/cr1002722; (c) G. Dorman,
in Bioorganic Chemistry of Biological Signal Transduction, Springer-
Verlag, Berlin, 2001, 211, 169–225; (d) T. Tomohiro, M. Hashimoto
and Y. Hatanaka, Chem. Rec., 2005, 5, 385–395; (e) Y. Hatanaka
and Y. Sadakane, Curr. Top. Med. Chem., 2002, 2, 271–288; (f) F.
Kotzybahibert, I. Kapfer and M. Goeldner, Angew. Chem., Int. Ed.
Engl., 1995, 34, 1296–1312.
23 (a) F. Ford, T. Yuzawa, M. S. Platz, S. Matzinger and M. Fu¨lscher, J.
Am. Chem. Soc., 1998, 120, 4430–4438; (b) J. P. Toscano, M. S. Platz
and V. Nikolaev, J. Am. Chem. Soc., 1995, 117, 4712–4713.
24 M. W. Turner, Immunobiology, 1998, 199, 327.
25 Paul Furuta and Jean M. J. Frechet, J. Am. Chem. Soc., 2003, 125,
13173.
26 Column: Agilent Eclipse XDB-C18 PN 990967-202. Gradient: 20% to
100% of acetonitrile in water with 0.05% TFA (5 ml min-1) over 35 min.
27 Column: Agilent Eclipse XDB-C18 PN 990967-202. Gradient: 40% to
70% of acetonitrile in water with 0.05% TFA over 20 min followed by
100% acetonitrile for 5 min (5 ml min-1).
Notes and references
1 (a) N. M. Green and E. J. Toms, Biochem. J., 1973, 133, 687; (b) G. O.
Reznik and T. Sano, Bioconjugate Chem., 2001, 12, 1000.
2 (a) M. C. Posewitz and P. Tempst, Anal. Chem., 1999, 71, 2883; (b) F.
Helfferich, Nature, 1961, 189, 1001; (c) J. Porath and G. Belfrage,
Nature, 1975, 258, 598.
3 L. Nilsson Carol, Anal. Chem., 2003, 75, 348A.
4 (a) A. E. Speers and B. F. Cravatt, Chem. Biol., 2004, 11, 535; (b) A. E.
Speers and B. F. Cravatt, J. Am. Chem. Soc., 2003, 125, 4686.
5 H. Steen and M. Mann, J. Am. Soc. Mass Spectrom., 2003, 14, 83.
6 Y. Oda, T. Nagasu and B. T. Chait, Nat. Biotechnol., 2001, 19, 379.
7 (a) J. A. Gladysz, Chem. Rev., 2002, 102, 3215; (b) J. A. Gladysz and D.
P. Curran, Tetrahedron, 2002, 58, 3823; (c) M. Wende and J. A. Gladysz,
J. Am. Chem. Soc., 2003, 125, 5861.
8 (a) W. Zhang, Chem. Rev., 2009, 109, 749; (b) J. Yoshida and K. Itami,
Chem. Rev., 2002, 102, 3693.
6292 | Org. Biomol. Chem., 2011, 9, 6284–6292
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