Heck functionalization of an asymmetric aza-BODIPY core: synthesis of far-red infrared probes for bioimaging applications

Article abstract of DOI:10.1039/C6OB02602H

As part of our ongoing work on the synthesis of a new class of plant hormones named Strigolactones (SLs) and their analogues, we became interested in tracing bioactive molecules with red emitting BODIPY fluorophores in order to unravel signaling and distribution of SLs in plants. In this paper we report on an unprecedented Heck functionalization of azadipyrromethenes (aza-DIPY) which allows for the introduction of suitable functional groups to convert aza-BODIPY in bioconjugate complexes useful for untangling biological processes.

Full text of DOI:10.1039/C6OB02602H

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Takeharu Haino et al.
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ARTICLE
Heck Functionalization of Asymmetric Aza-Bodipy Core: Synthesis
of Far-Red Infrared Probes for Bioimaging Applications
Stefano Parisotto,a Beatrice Lace,a Emma Artuso,a Chiara Lombardi,a Annamaria Deagostino,a
Roberto Scudu,a Claudio Garino,a Claudio Medana,b and Cristina Prandia
Received 00th January 20xx,
Accepted 00th January 20xx
DOI: 10.1039/x0xx00000x
As part of our ongoing work on the synthesis of a new class of plant hormones named Strigolactones (SLs) and their
analogues, we became interested in tracing the bioactive molecules with red emitting BODIPY fluorophores in order to
unravel signaling and distribution of SLs in plants. In this paper we report on an unprecedented Heck functionalization of
azadipyrromethenes (aza-DIPY) which allows for the introduction of suitable functional groups to convert aza-BODIPY in
bioconjugate complexes useful to untangle biological processes.
www.rsc.org/
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Journal Name
introduction of electron donating substituents at the 3,5
phenyl rings7 and the replacement of the phenyl with
tiophene8 induce a bathochromic shift (2 and 3 Figure 2, 714
and 732 nm respectively).
Introduction
The synthesis of fluorescent tagged compounds has become
an increasingly attractive approach to transform the
chemical and biological information into detectable signals
in living systems. Far red and near infrared1 emissive dyes
play a key role in the development of fluorescent probes for
bio-imaging studies as their long excitation/emission wave
length is associated with low cytotoxicity, minimal
background from biomolecules auto-florescence and deep
tissue penetration.2 Among the huge variety of fluorescent
dyes 4,4-difluoro-4-borat-3a,4a-diaza-s-indacene (BODIPY)
has gained a growing success in the last decades.3 This class
of compounds shows excellent features for biological
applications including intense absorption, high quantum
yield, narrow absorption and emission bands, good photo
and chemical stability, high solubility and resistance to self
aggregation. In the context of bio-imaging studies on living
organisms, BODIPY chromophores with excitation-emission
wavelengths falling in the far-red and near-infrared (650
nm-900 nm) are preferred. However, the BODIPY core in
itself shows absorption and emission wavelength between
490 and 505 nm, this means that to be useful as fluorescent
probes for in vivo investigation, the spectroscopic features
of the BODIPY core should be tuned and pushed towards
the red spectral region by designing and synthesizing
properly functionalized derivatives. On this base, different
N
B
1
N
B
2
N
B
3
N
N
N
N
N
N
F
F
F
F
F
F
S
S
CHCl3 φf= 0.32
CHCl3 φf = 0.46
CHCl3 φf = 0.36
H3CO
OCH3
λex = 650 nm
λex = 710 nm
λex = 688 nm
λem = 673 nm
λem = 732 nm
λem = 714nm
Ph
Ph
Ph
Ph
Ph
Ph
N
B
N
B
N
N
N
N
N
N
N
B
F
F
F
F
F
F
MeO
6
5
4
CHCl3 φf = 0.11
CHCl3 φf = 0.46
CHCl3 φf = 0.32
MeO
MeO
MeO
λex = 715 nm
λex = 668 nm
λex = 723 nm
λem = 692 nm
λem = 734 nm
λem = 730 nm
Figure 2. Structure of a selection of aza-BODIPY with photochemical
properties.
The traditional approach to 1,3,5,7 tetraaryl substituted aza-
BODIPY consists in the addition reaction between calchones
and nitromethane, or cyanide, followed by a condensation
reaction with ammonium acetate. Upon complexation with
BF3 Et2O the correspondent aza-BODIPYs are obtained.9
.
A
limitation of this route is that, being de facto the reaction a
dimerization process, only symmetrical derivatives
containing two pairs of aryl substituents can be generated.
Unsymmetrical systems, which would facilitate the
introduction of differing substituents on each of the aryl
rings, are much less accessible. This type of synthetic control
would be required for fine-tuning both spectroscopic and
solubility properties of the compounds and in addition
would allow the introduction of specific functional groups
for accessing bioconjugated analogues. To this purpose O’
Shea et al. chose a modular approach which consists in the
coupling of one-half of the molecule with the other by the
reaction of 2,4-diarylpyrroles with their corresponding
nitroso analogues (Scheme 1).10 Following this strategy,
Carreira et al. reported the synthesis of compounds 4-6
(Figure 2) with remarkable tunable optical properties.11
Despite recent advances in this direction, the
desymmetrization of the aza-BODIPY core remains
synthetically challenging.12
strategies to modify the BODIPY core and extend the
ú-
conjugation have been proposed and can be grouped into
the following three categories: a) functionalization at the α-,
β- and meso-sites of the BODIPY core to extend the
ú-
conjugation and to generate a “push-pull” structure;4 b)
employment of pyrroles fused with aromatic units at the [a]
or [b] bonds5 and c) replacement of the meso-carbon with
an imine type nitrogen in combination with strategies a)
and/or b).
meso
N
aza-BODIPY
β
8
7
5
1
[a] annulation
2
6
N
N
[b] annulation
B
3
F
F4
α
4'
Figure 1. Structure of the BODIPY core and sites of modification strategies
towards far red and NIR derivatives.
Ar4
Ar2
Ar1
Ar4
Ar3
Ar2
Ar2
Ar3
N
N
H
In particular, aza-BODIPY are BODIPY derivatives with the
carbon in the meso position replaced by an imine type
nitrogen atom. They show the same remarkable features
cited above for conventional BODIPY while at the same time
their absorption/emission spectra are largely shifted to the
red region. 1,3,5,7-Tetraaryl aza-BODIPY 1 (Figure 2) shows
absorption at 650 nm and emission at 673 nm.6 The
NH
N
Ar1
Ar1
NO
N
N
H
H
Scheme 1. Synthetic route to unsymmetrical Tetraarylazadipyrromethenes
As part of our ongoing work on the synthesis of a new class
of plant hormones named Strigolactones (SLs) and their
analogues, we became interested in tracing the bioactive
2 | J. Name., 2012, 00, 1-3
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molecules with red emitting BODIPY fluorophores in order
The reaction was performed at 100 °C in DMF. The same
conditions without TBAB led to a slightly lower yield (80%,
entry 8) while the removal of the base determined a drop in
the final yield to 14% (entry 10). LiCl proved to be ineffective
as an additive (yield < 5%, entry 13%). The Heck coupling
turned out to be very sensitive to the content of water.
Indeed, under rigorously anhydrous conditions the reaction
does not proceed, the highest yields were obtained with a
10% mol. content of water.
to unravel signaling and distribution of SLs in plants.13
Analogues functionalized with green emitting BODIPY have
already been synthetized by our group and observed in
plants,14 however the green auto florescence typical of
many plant structures hampers the application of green
emitting BODIPY-SLs on a wider base. In addition, the plan
of using fluorescent labeled SLs in combination with the GFP
tagged receptor prompted us in investigating new synthetic
strategies leading to red emitting asymmetric functionalized
BODIPY. To this purpose we chose [3-(4-Bromo-phenyl)-5-
phenyl-pyrrol-2-ylidene]-(3,5-
diphenyl-1H-pyrrol-2-yl)-
amine 7 (Scheme 2), previously synthesized by O’ Shea et
al.10a as a substrate to optimize the Heck functionalization
and thus be able to introduce functionalities suitable to
hook small active molecules of interest and map their
distribution in vivo.
Scheme 2. Heck functionalization of 1,3,5,7-tetraphenyl aza-DIPY core
Results and Discussion
Pd catalyzed cross couplings on symmetrical halogenated
BODIPYs have already been realized with moderate yields.15
By converse, only few reports on Sonogashira,16 Suzuki17 or
Heck couplings15 on symmetrically halogenated aza BODIPY
have been reported so far (Scheme 2). Since aza-BODIPY
have been found to be prone to the loss of BF2 fragment
under the cross coupling conditions,18 we decided to use 7
as precursor for the Heck reaction optimization.19
Eventually, the BF2 moiety was introduced classically using
.
BF3 OEt2 and DIPEA (Scheme 2). The optimization of the
reaction conditions is reported in Table 1. The best results
in terms of yield of isolated product were obtained using
Pd(OAc)2 10%/ (o-Tol)3P 20% as a catalyst in the presence of
TBAB as additive and Bu3N as a base (see entry 12).
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Table 1. Optimization conditions for the Heck reaction
O
OtBu
Br
O
Ph
Ph
Ph
Ph
N
N
OtBu
NH
N
NH
N
Ph
Ph
8a
7
Temp Time
conv yield
Entry
Base
Catalyst
Solvent
Additive
(C°)
100
100
120
90
(hs)
16
16
8
1
2
Et3N
K2CO3
NaOAc
Et3N
Pd(OAc)2 10%, (o-Tol)3P 20%
Pd(PPh3)4 10%
DMF
DMSO
TBAB
DMF
DMF
DMF
DMF
DMF
DMF
DMF
DMF
DMF
DMF
DMF
DMF
-
62
42
80
60
60
90
10
85
17
46
15
91
11
77
46
43
<1
25
28
28
42
5
-
3
Pd(OAc)2 10%
-
4
Pd(OAc)2 10%, (o-Tol)3P 20%
Pd(OAc)2 10%, (o-Tol)3P 20%
Pd(OAc)2 10%, (o-Tol)3P 20%
Pd(OAc)2 10%, (o-Tol)3P 20%
Pd(OAc)2 10%, (o-Tol)3P 20%
Pd(OAc)2 10%, (o-Tol)3P 20%
Pd(OAc)2 10%, (o-Tol)3P 20%
Pd(OAc)2 10%
-
16
16
16
16
16
16
16
16
6.5
6.5
16
16
5*
6
Et3N
-
100
115
100
100
100
100
100
100
100
100
100
Et3N
-
7
NaOAc an.
Bu3N
-
8
-
80
7
9
K2CO3 aq
-
-
10
11
12
13
14
15
-
14
<5
90
<5
61
45
Bu3N
-
Bu3N
Pd(OAc)2 10%, (o-Tol)3P 20%
Pd(OAc)2 10%, (o-Tol)3P 20%
PdCl2 10%, (o-Tol)3P 20%
Pd(OAc)2 5%, (o-Tol)3P 10%
TBAB 40%
LiCl 100%
TBAB 20%
TBAB 20%
Bu3N
Bu3N
Bu3N
Reactions were conducted in the presence of 2 equiv of t-Bu acrylate and 2 equiv of base. * 3 equiv of t-Bu acrylate and 3 equiv of base. Conversions have been
estimated on the base of recovered 7 after purification from the crude, yields have been calculated on purified and isolated compounds. DMF was used in
combination with 10% mol. of water.
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COOtBu
with a less stereochemical control (8c, 4:1 E:Z). Depending on
the reaction conditions, the use of acrolein dimethyl acetal
could lead to either cynnamaldehyde derivatives or to 3-
arylpropanoate esters 8d.22 This is due to the involvement of
both β-hydrogens in the elimination step from the
carbapalladation intermediate. In our case the chosen
conditions prompt the formation of the ketene intermediate
upon whose hydrolisys the propanoate ester was obtained
with complete chemoselectivity. A series of 1-alkenyl alcohols
have been then considered, allylic alcohol (8e), 5-hexen-1-ol
(8f), and 10-undecen-1-ol (8g) respectively. It was previously
reported that under Pd catalysis conditions the double bond
isomerization of these substrates leads to the formation of the
corresponding saturated aldehydes.23 A trend in the ratio
aldehyde: alcohol obtained as final products depending on the
length of the chain was observed. With allylic alcohol the
corresponding aldehyde (8e) was obtained as single product,
switching to 5-hexen-1-ol and to 10-undecen-1-ol the ratio
changes to 4: 1 and to 10: 1 in favor of the alcohol. Complete E
stereoselectivity was observed with 1-ottene (8h), with methyl
vinyl ketone (8i) and with 11-azidoundec-1-ene (8j). The
reaction conditions were also tested on enol ether (E) 4-
ethoxy-1,3-octadiene (8k) even though the yield in this case is
lower. Remarkably the vinyl ether function is stable under
these conditions. Among the products 8a-8k showed in Figure
3 we chose those more suitable to be hooked to biological
active molecules and prepared the corresponding aza-BODIPY
derivatives following standard procedures (see SI). The
spectroscopic data of the obtained aza-BODIPY derivatives for
compound 7’, 8a’, 8j’ obtained respectively from 7, 8a, 8j and
for 10 (see Scheme 3) are reported in Table 3. The values are in
line with data reported in the literature.24
OiBu
CN
Ph
N
Ph
Ph
Ph
Ph
N
N
NH
N
NH
N
NH
N
Ph
Ph
Ph
Ph
8c
8a
E:Z 10:0
8b
E:Z 9:1
(88)
E:Z 4:1
(90)
(75)
OH
COOMe
CHO
2
Ph
Ph
Ph
Ph
N
NH
N
N
N
NH
N
NH
N
Ph
Ph
Ph
Ph
Ph
8d
8f (78)
E:Z 10:0
(70)
8e
(70)
OH
O
8
5
Ph
Ph
Ph
Ph
Ph
N
N
N
NH
N
NH
N
NH
N
Ph
Ph
Ph
Ph
8g (78)
E:Z 10:0
8i
8h (83)
E:Z 10:0
(81)
E:Z 10:0
N3
C4H9
OEt
7
Ph
Ph
N
N
NH
N
NH
N
Ph
Ph
Ph
Ph
8j (76)
E:Z 10:0
8k (45)
E:Z 10:0
Figure 3. Scope of the reaction. Yields reported in brackets refer to isolated and
purified products
As aza-DIPY have been reported to form heteroleptic
complexes with many metals including Pd,20 we speculated
that our substrate 7 can serve as a competitive bidentate
ligand to one of the catalytically active metal species and then
prevent the catalyst to enter the catalytic cycle. However,
further mechanistic investigation are ongoing to elucidate the
crucial role of water in promoting the coupling. The scope of
the reaction was then investigated with special focus on the
introduction of functional groups suitable for hooking
bioactive molecules and turn them in in vivo traceable entities.
The optimized conditions set in Table 1 were applied to So,
isobutyl vinyl ether smoothly reacted to give the
corresponding Heck product 8b with good yield functionalized
terminal alkenes. and with a good stereoselectivity (9:1 in
favor of the E isomer). The unusual observed regioselectivity is
in agreement with previous findings reporting Heck reactions
on bulky vinyl ethers.21 Acrylonitrile also gave a good yield but
Table 3. Spectroscopic properties of Heck functionalized aza-BODIPY derivatives (CHCl3
solution)
Compound
λ
ex (nm)
650
λ
em (nm)
677
Φfa
τ
(ns)b
0.7
0.8
0.6
0.5
7’
8a’
8j’
10
0.10
0.14
0.13
0.18
660
685
660
685
658
685
aabsolute fluorescence quantum yields (Φf) were determined using an
integrating sphere. b lifetimes were determined upon excitation at 636 nm.
Once the synthetic feasibility to access the functionalized aza-
BODIPY has been assessed, we stepped forward to the synthesis of
a suitable probe to investigate the penetration and distribution of
SLs in plant cells and tissues. To this purpose we choose to rely on a
partial agonist of SLs and functionalize it with azido aza-BODIPY 8j’.
N-(4-ethynylphenyl)-4-methylbenzenesulfonamide
9
was then
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ARTICLE
Journal Name
tests of compound 10
ꢀ
,
(E). Bars = 20 m in (A, B, C) and 40
8j’ and CL-BP vs GR24 on seeds of Phelipanche aegyptiaca
m in (D).
subjected to click chemistry and coupled with 8j’ in the presence of
ꢀ
DIPEA and CuI (Scheme 3, see SI).
Based on these data we than designed both red emitting
compound 10 and the correspondent green emitting version
CL-BP using a BODIPY core as fluorescent probe.27 The activity
N
N
N
N3
9
9
of 10
ability on seeds of Phelipanche aegyptiaca (Figure 4, D). As
expected they are less active than the reference GR24
however at 10-5
concentration they show activity.
, CL-BP and 8j’ as a reference were tested as germination
NH
O2S
NH
O2S
Ph
Ph
Ph
Ph
,
N
B
N
B
DIPEA, CuI
+
M
N
N
N
N
CH3
Preliminary observations on plant tissues indicate that the
compounds penetrate and distribute in the biological
environment and fluorescence is clearly detectable. Further
observations and biochemical investigations are planned to
validate the biological significance of the fluorescence
distribution.
Ph
F
F
Ph
F
F
CH3
9
8j'
10
Scheme 3. Synthesis of the fluorescent bioactive analogue.
Spectroscopic properties of 10 are reported in Table 3.
Preliminary observations and biological significance. The
molecular mechanism at the base of SLs perception is still
under discussion, but there is now a body of evidence that
once entered in the receptor the SL undergoes hydrolysis and
part of the molecule is released.25 SAR (Structure Activity
Relationship) data on a huge number of natural and synthetic
SLs suggest that modifications that do not jeopardize the
biological activity of the molecule are exclusively allowed
exactly on the part of the molecule that is released after
perception. This means that when designing bioconjugates of
SLs, the fluorescent probe has to be linked to the portion of
the molecule that is released and this may lead to
misinterpretation of the results. We have already synthesized
green emitting BODIPY-SLs derivatives (GR24-BP, see Figure
4D) and they have been successfully used to study the
transport of SLs, however for the above cited reasons they
cannot be used to localize the receptor.14b An alternative
approach consists in exploiting non-hydrolysable agonist or
antagonists of SLs and functionalize them with our probes.
Cotylimides (CTL) are sulfonamide derivatives that have been
reported to bind the SLs receptor and induce biological effects
related to SLs.26
Conclusions
This work is part of a more general study focused on the
identification of the receptor and elucidate the mode of action
of bioactive molecules known as SLs. Our contribution to this
topic is the design and synthesis of fluorescent labelled SL
analogues to be used as probes for the in vivo distribution.
With the aim of synthesizing red emitting probes suitable to be
hooked to bioactive molecules, we have accomplished an
unprecedented Heck functionalization of the aza-BODIPY core.
The reaction has been optimized on the aza-DIPY nucleus and
remarkably
a number of useful functional groups were
introduced. From the above results, we designed a promising
candidate for our imaging studies, preliminary observations on
biological samples are presently ongoing and confirm
expectations.
Experimental
General Details. Flasks and all equipment used for the
generation and reaction of moisture-sensitive compounds
were dried by electric heat gun under nitrogen. All reactions
involving air-sensitive reagents were performed under a dry
nitrogen atmosphere. DMF was purchased from Sigma Aldrich.
Anhydrous CH2Cl2 was obtained by distillation from CaH2.
Reagents were used as received if not otherwise specified, or
prepared according to the literature procedures. Reactions
were monitored by TLC using silica-gel on TLC-PET foils Fluka,
2-25 μm, layer thickness 0.2 mm, medium pore diameter 60 Å.
1H NMR spectra were recorded at 200 MHz, 13C NMR spectra
at 50.2 MHz, in CDCl3. Data were reported as follows: chemical
shifts in ppm from Me4Si as an internal standard, multiplicity,
integration, coupling constants (Hz), and assignment. 13C NMR
spectra were measured with complete proton decoupling.
Chemical shifts were reported in ppm from the residual pick
solvent as an internal standard. Infrared spectra were acquired
using a Perkin Elmer Spectrum Two ATR-FTIR spectrometer.
Photochemical Characterization of Fluorescent Derivatives.
UV-Vis absorption and photoemission spectra, together with
luminescence lifetimes and quantum yields, were recorded in
Figure
concentration of compound 10 (A), 8j’ (B)
4. M
Confocal images showing A. thaliana roots treated with 10-5
,
CL-BP (C), GR24-BP (D) and biological chloroform solution at room temperature. Absorption spectra
6 | J. Name., 2012, 00, 1-3
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were acquired on an Agilent Cary 60 UV-Vis spectrometer, (E)-3-(4-((Z)-2-((3,5-diphenyl-1H-pyrrol-2-yl)imino)-5-phenyl-
while photoemission spectra, luminescence lifetimes and 2H-pyrrol-3-yl)phenyl) acrylonitrile (8c). Dark blue metallic
quantum yields were obtained on a HORIBA Jobin Yvon IBH solid, (yield 88 %), m.p. 253−255 °C, TLC Rf = 0.55 (EP/CH2Cl2
Fluorolog-TCSPC spectrofluorometer equipped with a Quanta- 3/7, v/v). H NMR (200 MHz, CDCl3) δ (ppm): 8.10 (d, 2H, J =
1
ϕ
integrating sphere. The luminescence lifetimes were 8.0 Hz, Ar
determined by time-correlated single-photon counting; 7.37 7.60 (m, 12H, Ar
excitation was achieved with nanosecond pulses of 636 nm 7.15 (s, 1H, Pyrr
−
H), 7.98 (m, 4H, Ar
−
H and CNCH=CH), 7.23 (s, 1H, Pyrr
H), 7.87 (m, 2H, Ar
−
H),
H),
−
−
−
−
H), 5.90 (d, 1H, J = 16.6 Hz, CNCH=CH), (NH
light generated by a NanoLED pulsed diode. Emission-decay not observed). 13C NMR (50.2 MHz, CDCl3) δ (ppm): 158.5 (Cq),
data were collected in 2048 channels to 10000 counts in the 151.8 (Cq), 151.5 (Cq), 150.0 (CH), 147.0 (Cq), 144.0 (Cq), 138.5
peak channel and analysed with the software DAS6 (TCSPC (Cq), 133.0 (Cq), 132.5 (Cq), 132.0 (CH), 131.9 (Cq), 131.7 (Cq),
decay-analysis software).
130.5 (CH), 129.7 (CH), 129.2 (CH), 129.0 (CH), 127.6 (CH),
Synthetic Procedures. Typical Heck procedure. In a reaction 127.4 (CH), 127.1 (CH), 126.8 (CH), 126.1 (CH), 124.4 (CH),
tube, 4 mL of DMF are thoroughly degassed for 30 minutes by 121.5 (Cq), 118.0 (Cq), 116.6 (CH), 113.5 (CH), 95.6 (CH),. IR
bubbling nitrogen. Then the aryl bromide (53.0 mg, 0.10 mmol, cm-1: 3445, 2924, 2215, 1596, 1536, 1261, 1242, 964, 902, 762,
+
1.0 eq), a suitable alkene (0.20 mmol, 2.0 eq), tributylamine 685. m/z (HR, ESI) for C35H25N4 Calcd 501.2074 [M + H]+.
(48
eq), Pd(OAc)2 (2.2 mg, 0.01 mmol, 0.10 eq) and (o-Tol)3P (6.1 (Z)-methyl
mg, 0.02 mmol, 0.20 eq) are added all in once. The tube is phenyl-2H-pyrrol-3-yl)phenyl) propanoate (8d). Dark blue
sealed and the dark blue solution is stirred at 100°C for 8 metallic solid, (yield 69%), m.p. 188 190 °C, TLC Rf = 0.52
hours. After cooling down, the reaction mixture is diluted with (EP/CH2Cl2 35/65, v/v). H NMR (200 MHz, CDCl3) δ (ppm):
ethyl acetate, washed with saturated ammonium chloride 7.92 8.08 (m, 8H, Ar H), 7.38 7.58 (m, 9H, Ar H), 7.26 (d, 2H,
(1x15 mL) and brine (1x15 mL). The organic phase is dried over J = 8.0 Hz, Ar H), 7.19 (s, 1H, Pyrr H), 7.18 (s, 1H, Pyrr H),
Na2SO4, filtered and the solvent is removed under reduced 3.72 (s, 3H, OCH3), 3.04 (t, 2H, J = 7.5, 2.0 Hz, COCH2), 2.85 (tm,
pressure to afford a dark solid that is purified by column.
2H, J = 7.5 Hz, COCH2CH2), (NH not observed). 13C NMR (50.2
ꢀ
L mg, 0.3 mmol, 2.0 eq), TBAB (12.8 mg, 0.040 mmol, 0.4 Found 501.2068 [M + H]+.
3-(4-(2-((3,5-diphenyl-1H-pyrrol-2-yl)imino)-5-
−
1
−
−
−
−
−
−
−
(E)-tert-butyl 3-(4-((Z)-2-((3,5-diphenyl-1H-pyrrol-2-yl)imino)- MHz, CDCl3) δ (ppm): 173.1 (Cq), 155.3 (Cq), 154.2 (Cq), 149.7
5-phenyl-2H-pyrrol-3-yl)phenyl) acrylate (8a). Dark blue (Cq), 149.0 (Cq), 142.3 (Cq), 142.1 (Cq), 140.2 (Cq), 133.6 (Cq),
metallic solid (yield 90%), m.p. 225−227 °C, TLC Rf = 0.45 132.0 (Cq), 131.9 (Cq), 131.6 (Cq), 129.8 (CH), 129.7 (CH),
(EP/CH2Cl2 1/1, v/v). 1H NMR (200 MHz, CDCl3) δ (ppm): 129.0 (CH), 128.9 (CH), 128.0 (CH), 127.7 (CH), 126.4 (CH),
7.75
−
−
8.10 (m, 8H, Ar
−H), 7.62 (d, 1H, J = 16.0 Hz, COCH=CH), 126.3 (CH), 126.2 (CH), 114.4 (CH), 51.5 (CH3), 35.5 (CH2), 30.6
7.30
7.55 (m, 11H, Ar−
H), 6.41 (d, 1H, J = 16.0 Hz, COCH=CH), 1.60 (s, 9H, CH3), 759, 685. m/z (HR, ESI) for C36H30N3O2 Calcd 536.2333 [M +
H), 7.14 (s, 1H, Pyrr
−
H), 7.08 (s, 1H, (CH2). IR cm-1: 3262, 3055, 2924, 1719, 1551, 1242, 957, 904,
+
Pyrr
−
(NH not observed). 13C NMR (50.2 MHz, CDCl3) δ (ppm): 166.3 H]+. Found 536.2350 [M + H]+.
(Cq), 156.9 (Cq), 152.7 (Cq), 150.8 (Cq), 148.1 (Cq), 143.3 (Cq), (Z)-3-(4-(2-((3,5-diphenyl-1H-pyrrol-2-yl)imino)-5-phenyl-2H-
143.2 (CH), 140 (Cq), 135.2 (Cq), 133.6 (Cq), 133.3 (Cq), 131.9 pyrrol-3-yl)phenyl)propanal (8e). Dark blue metallic solid,
(Cq), 131.6 (Cq), 130.1 (CH), 129.6 (CH), 128.9 (CH), 128.0 (CH), (yield 70%), m.p. 175−177 °C, TLC Rf = 0.57 (EP/CH2Cl2 3/7, v/v).
127.7 (CH), 126.5 (CH), 126.1 (CH), 119.6 (CH), 115.6 (CH), 1H NMR (200 MHz, CDCl3) δ (ppm): 9.89 (t, 1H, J = 2.0 Hz,
113.7 (CH), 80.3 (Cq), 28.1 (CH3). IR cm-1: 2962, 1705, 1635, CHO), 7.92
−
8.07 (m, 8H, Ar
H), 7.18 (s, 1H, Pyrr
H), 3.03 (td, 2H, J = 7.5, 2.0 Hz, CHOCH2), 2.85 (tm, 2H, J =
7.5 Hz, CHOCH2CH2), (NH not observed). 13C NMR (50.2 MHz,
−
H), 7.37
−
7.58 (m, 9H, Ar
−H), 7.25
+
1005, 902, 579, 680. m/z (HR, ESI) for C39H34N3O2 Calcd (d, 2H, J = 8.0 Hz, Ar
−
−
H), 7.17 (s, 1H,
576.2646 [M + H]+. Found 576.2664 [M + H]+.
Pyrr−
(Z)-N-(3-(4-((E)-2-isobutoxyvinyl)phenyl)-5-phenyl-2H-pyrrol-
2-ylidene)-3,5-diphenyl-1H-pyrrol-2-amine (8b). Dark blue CDCl3) δ (ppm): 201.3 (Cq), 155.2 (Cq), 154.4 (Cq), 149.7 (Cq),
metallic solid, (yield 75 %), m.p. 214 216 °C, TLC Rf = 0.69 149.1 (Cq), 142.1 (Cq), 140.0 (Cq), 133.8 (Cq), 131.9 (Cq), 139.1
(EP/CH2Cl2 1/1, v/v). 1H NMR (200 MHz, CDCl3) δ (ppm): (Cq), 131.6 (Cq), 129.8 (CH), 129.7 (CH), 129.0 (CH), 128.9 (CH),
7.85 8.15 (m, 8H, Ar H), 7.35 7.60 (m, 9H, Ar H), 7.26 (d, 1H, 128.0 (CH), 127.7 (CH), 126.3 (CH), 126.2 (CH), 114.4 (CH), 45.1
J = 10.0 Hz, Ar H), 7.17 (s, 1H, Pyrr H), 7.16 (s, 1H, Pyrr
H), (CH2), 27.8 (CH2). IR cm-1: 3262, 3055, 2924, 1719, 1551, 1242,
−
−
−
−
−
−
−
−
7.13 (d, 1H, J = 13.0 Hz, COCH=CH), 5.90 (d, 1H, J = 13.0 Hz, 957, 904, 759, 685. m/z (HR, ESI) for C35H28N3O+ Calcd
COCH=CH), 3.67 (d, 2H, J = 8.0 Hz, CH2), 2.06 (m, 1H, J = 8.0 Hz, 506.2227 [M + H]+. Found 506.2216 [M + H]+.
CHCH3), 1.06 (d, 6H, J = 8.0 Hz, CH3), (NH not observed). 13C (E)-6-(4-((Z)-2-((3,5-diphenyl-1H-pyrrol-2-yl)imino)-5-phenyl-
NMR (50.2 MHz, CDCl3) δ (ppm): 156.1 (Cq), 153.3 (Cq), 150.4 2H-pyrrol-3-yl)phenyl)hex-5-en-1-ol (8f). Dark blue metallic
(Cq), 148.6 (CH), 148.5 (Cq), 142.8 (Cq), 141.1 (Cq), 136.4 (Cq), solid, (yield 64%), m.p. 164
−
162 °C, TLC Rf = 0.45 (EP/CH2Cl2 ,
133.7 (Cq), 132.1 (Cq), 131.9 (Cq), 130.8 (Cq), 129.8 (CH), 129.6 85/15 v/v). H NMR (200 MHz, CDCl3) δ (ppm): 7.89 8.09 (m,
(CH), 129.1 (CH), 128.9 (CH), 128.0 (CH), 127.6 (CH), 126.4 8H, Ar H), 7.30 7.60 (m, 11H, Ar H), 7.20 (s, 2H, Pyrr H), 6.35
1
−
−
−
−
−
(CH), 126.2 (CH), 124.6 (CH), 114.2 (CH), 114.0 (CH), 105.4 (m, 2H, CH=CH) 3.70 (t, 2H, J = 7.0 Hz, CH2OH), 2.35 (m, 2H,
(CH), 76.4 (CH2), 28.2 (CH), 19.0 (CH3). IR cm-1: 3045, 2924, CH=CHCH2), 1.65 (bs, 4H, 2XCH2), (NH, OH not observed). 13C
1633, 1543, 1350, 1239, 1133, 957, 902, 757, 685. m/z (HR, NMR (50.2 MHz, CDCl3) δ (ppm): 155. 3 (Cq), 154.3 (Cq), 149.8
ESI) for C38H34N3O+ Calcd 548.2696 [M + H]+. Found 548.2684 (Cq), 149.1 (Cq), 142.3 (Cq), 142.2 (Cq), 137.3 (Cq), 135.0 (Cq),
[M + H]+.
133.6 (Cq), 132.1 (Cq), 132.0 (Cq), 131.9 (Cq), 130.8 (CH), 129.8
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J. Name., 2013, 00, 1-3 | 7

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DOI: 10.1039/C6OB02602H
ARTICLE
Journal Name
(CH), 129.7 (CH), 128.9 (CH), 128.7 (CH), 128.0 (CH), 127.7 blue metallic solid, (yield 63%), m.p. 164
−
166 °C, TLC Rf = 0.50
(CH), 126.4 (CH), 126.3 (CH), 125.6 (CH), 125.2 (CH), 114.5 (EP/CH2Cl2 55/45, v/v). H NMR (200 MHz, CDCl3) δ (ppm):
(CH), 114.4 (CH), 62.7 (CH2), 32.7 (CH2), 32.1 (CH2), 25.3 (CH2).. 12.65 (bs, 1H, NH), 7.93 8.06 (m, 8H, Ar H), 7.41 7.54 (m,
IR cm-1 3344, 2987, 2852, 1451, 1276, 1251, 754, 749. m/z (HR, 11H, Ar
H), 7.19 (s, 1H, Pyrr H), 7.18 (s, 1H, Pyrr H), 6.33 (m,
ESI) for C38H34N3O+ Calcd 548.2696 [M + H]+. Found 548.2709 2H, CH=CH), 3.26 (t, 2H, J = 8.0 Hz, CH2N3), 2.27 (q, 2H, J = 6.0
1
−
−
−
−
−
−
[M + H]+.
Hz, CH=CHCH2), 1.49−1.66 (m, 4H, CH=CHCH2 and CH2CH2N3),
(E)-11-(4-((Z)-2-((3,5-diphenyl-1H-pyrrol-2-yl)imino)-5-phenyl- 1.35 (bs, 10H, 5XCH2). 13C NMR (50.2 MHz, CDCl3) δ (ppm):
2H-pyrrol-3-yl)phenyl)undec-10-en-1-ol (8g). Dark blue 155.4 (Cq), 154.1 (Cq), 149.8 (Cq), 149.0 (Cq), 142.2 (Cq), 141.9
metallic solid, (58 %), m.p. 183
−
186 °C, TLC Rf = 0.60 (EP/CH2Cl2 (Cq), 137.4 (Cq), 133.6 (Cq), 131.9 (Cq), 131.4 (CH), 129.8 (CH),
0/100, v/v). H NMR (200 MHz, CDCl3) δ (ppm): 7.90 8.09 (m, 129.7 (CH), 129.5 (CH), 128.9 (CH), 128.6 (CH), 128.0 (CH),
8H, Ar H), 7.40 7.52 (m, 11H, Ar H), 7.17 (s, 1H, Pyrr H), 7.16 127.7 (CH), 126.4 (CH), 126.2 (CH), 125.6 (CH), 114.3 (CH),
(s, 1H, Pyrr
1
−
−
−
−
−
−
H), 6.35 (m, 2H, CH=CH), 3.66 (td, 2H, J = 6.0, 2.0 114.2 (CH), 51.3 (CH2), 33.0 (CH2), 29.4 (CH2), 29.3 (CH2), 29.2
Hz, CH2OH), 2.27 (q, 2H, J = 6.0 Hz, CH=CHCH2), 2.10 (bs, 1H, (CH2), 29.1 (CH2), 29.0 (CH2),28.7 (CH2), 26.5 (CH2). IR cm-1:
OH), 1.56 (m, 4H, CH=CHCH2 and CH2CH2OH), 1.36 (bs, 10H, 3055, 2924, 2852, 2094, 1540, 1347, 1259, 1242, 960, 904, 759
5XCH2), (NH not observed). 13C NMR (50.2 MHz, CDCl3) δ m/z (HR, ESI) for C43H43N6 Calcd 643.3544 [M + H]+. Found
(ppm): 155. 4 (Cq), 154.1 (Cq), 149.9 (Cq), 149.0 (Cq), 142.3 643.3546 [M + H]+.
+
(Cq), 142.0 (Cq), 137.5 (Cq), 133.6 (Cq), 132.0 (Cq), 131.9 (Cq), (Z)-N-(3-(4-((1E,3E)-4-ethoxyocta-1,3-dien-1-yl)phenyl)-5-
131.5 (CH), 129.9 (CH), 129.7 (CH), 129.4 (CH), 128.9 (CH), phenyl-2H-pyrrol-2-ylidene)-3,5-diphenyl-1H-pyrrol-2-amine
128.0 (CH), 127.7 (CH), 126.3 (CH), 125.6 (CH), 125.2 (CH), (8h). Dark blue metallic solid, (yield 43%), m.p. 198
−
200 °C,
114.4 (CH), 114.3 (CH), 62.9 (CH2), 33.0 (CH2), 32.6 (CH2), 29.4 TLC Rf = 0.80 (EP/CH2Cl2 1/1, v/v). H NMR (200 MHz, CDCl3) δ
(CH2), 29.2 (CH2), 25.6 (CH2). IR cm-1 3310, 2929, 2852, 1543, (ppm): 8.00
8.11 (m, 4H, Ar H), 7.90 7.99 (m, 4H, Ar H),
7.60 (m, 11H, Ar H), 7.19 (s, 2H, Pyrr H), 7.00 (dd, 1H, J
= 16.0, 10.0 Hz, ArCH=CH), 6.40 (d, 1H, J = 16.0 Hz, ArCH=CH),
5.48 (d, 1H, J = 10.0 Hz, ArCH=CH CH), 3.85 (q, 2H, J = 8.0 Hz,
1.65 (m, 4H,
x177 °C, TLC Rf = 0.67 COCH2CH2), 1.36 (t, 3H, J = 8.0 Hz, OCH2CH3), 0.99 (t, 3H, J = 8.0
(EP/CH2Cl2 65/35, v/v). H NMR (200 MHz, CDCl3) δ (ppm): Hz, OCH2 CH2 CH2CH3), (NH not observed). 13C NMR (50.2 MHz,
7.92 8.08 (m, 8H, Ar H), 7.36 7.58 (m, 11H, Ar H), 7.18 (s, CDCl3) δ (ppm): 161.5 (Cq), 155.9 (Cq), 153.6 (Cq), 150.2 (Cq),
1H, Pyrr H), 7.17 (s, 1H, Pyrr H), 6.37 (m, 2H, CH=CH), 2.27 (q, 148.7 (Cq), 142.6 (Cq), 141.8 (Cq), 138.3 (Cq), 133.7 (Cq), 132.0
2H, J = 6.0 Hz, CH=CHCH2), 1.35 1.53 (m, 8H, 4xCH2), 0.93 (t, (Cq), 131.9 (Cq), 131.4 (Cq), 129.8 (CH), 129.6 (CH), 129.0 (CH),
1
−
−
−
−
1273, 1251, 751, 747. m/z (HR, ESI) for C43H44N3O+ Calcd 7.35
618.3479 [M + H]+. Found 618.3499 [M + H]+.
−
−
−
(Z)-N-(3-(4-((E)-oct-1-en-1-yl)phenyl)-5-phenyl-2H-pyrrol-2-
−
ylidene)-3,5-diphenyl-1H-pyrrol-2-amine (8h). Dark blue OCH2CH3), 2.43 (t, 3H, J = 8.0 Hz, COCH2), 1.30
−
metallic solid, (yield 83%), m.p. 174
−
1
−
−
−
−
−
−
−
3H, J = 6.0 Hz, CH3), (NH not observed). 13C NMR (50.2 MHz, 128.9 (CH), 128.0 (CH), 127.6 (CH), 126.4 (CH), 126.2 (CH), ,
CDCl3) δ (ppm): 154. 4 (Cq), 154.0 (Cq), 149.9 (Cq), 149.0 (Cq), 126.0 (CH), 125.6 (CH), 125.2 (CH), 114.2 (CH), 114.1 (CH),
142.3 (Cq), 141.9 (Cq), 137.4 (Cq), 133.6 (Cq), 132.8 (Cq), 131.9 100.4 (CH), 62.4 (CH2), 30.7 (CH2), 30.0 (CH2), 22.2 (CH2), 14.4
(Cq), 131.7 (Cq), 131.5 (CH), 129.8 (CH), 129.6 (CH), 129.4 (CH), (CH3), 13.8 (CH3). IR cm-1: 3045, 2924, 1633, 1536, 1350, 1621,
128.8 (CH), 128.6 (CH), 128.0 (CH), 127.6 (CH), 126.4 (CH), 1169, 962, 904, 757, 687. m/z (HR, ESI) for C42H40N3O Calcd
126.2 (CH), 125.6 (CH), 125.2 (CH), 114.3 (CH), 114.2 (CH), 33.1 602.3166 [M + H]+. Found 602.3170 [M + H]+.
(CH2), 31.6 (CH2), 29.2 (CH2), 28.8 (CH2), 22.5 (CH2), 14.0 (CH3). Synthesis of the fluorescent complexes. In a flame dried
IR cm-1: 2924, 2852, 1733, 1455, 1276, 1251, 754, 750. m/z Schlenk flask a solution of the azadipyrromethene (0.10 mmol,
+
(HR, ESI) for C40H38N3 Calcd 560.3060 [M + H]+. Found 1.0 eq) and DIPEA (0.174 mL, 1.0 mmol, 10.0 eq) in anhydrous
560.2696 [M + H]+.
CH2Cl2 (10 mL) is stirred at room temperature for five minutes
under a N2 atmosphere. BF3·Et2O (0.18 mL, 1.4 mmol, 14.0 eq)
(E)-4-(4-((Z)-2-((3,5-diphenyl-1H-pyrrol-2-yl)imino)-5-phenyl-
2H-pyrrol-3-yl)phenyl) but-3-en-2-one (8i). Dark blue metallic is added dropwise. The reaction is monitored by TLC and the
solid, (yield 79%), m.p. 249 252 °C, TLC Rf = 0.36 (EP/CH2Cl2 mixture is reacted until disappearance of the blue spot. The
8/92, v/v). H NMR (200 MHz, CDCl3) δ (ppm): 7.86 8.13 (m, dark green solution is washed with distillated water (1x15 mL)
8H, Ar H), 7.42 7.60 (m, 12H, Ar H and COCH=CH), 7.22 (s, and brine (1x15 mL). The organic phase is dried over Na2SO4,
1H, Pyrr H), 7.16 (s, 1H, Pyrr H), 6.77 (d, 1H, J = 16.0 Hz, filtered and the solvent is removed under reduced pressure to
COCH=CH), 2.44 (s, 3H, CH3), (NH not observed). 13C NMR (50.2 afford
dark solid which is purified by column
−
1
−
−
−
−
−
−
a
MHz, CDCl3) δ (ppm): 198.3 (Cq), 156.9 (Cq), 152.7 (Cq), 150.8 chromatography on silica gel. Eluents: petroleum ether/CH2Cl2.
(Cq), 148.1 (Cq), 143.3 (Cq), 143.2 (CH), 140 (Cq), 135.2 (Cq), 1-(4-bromophenyl)-5,5-difluoro-3,7,9-triphenyl-5H-
133.6 (Cq), 133.3 (Cq), 131.9 (Cq), 131.6 (Cq), 130.1 (CH), 129.6 dipyrrolo[1,2-c:2',1'-f][1,3,5,2] triazaborinin-4-ium-5-uide (7).
(CH), 128.9 (CH), 128.0 (CH), 127.7 (CH), 126.5 (CH), 126.1 Dark green metallic solid, (yield 83%), TLC, Rf = 0.70 (EP/CH2Cl2
(CH), 119.6 (CH), 115.6 (CH), 113.7 (CH), 27.2 (CH3). IR cm-1: 7/3, v/v). 1H NMR (200 MHz, CDCl3) δ (ppm): 7.99
−
8.10 (m, 6H,
H), 7.59 (d, 2H, J = 8.8 Hz,
H). 13C NMR (50.2 MHz, CDCl3) δ
3059, 1559, 1546, 1352, 1261, 1242, 1172, 962, 796, 685. m/z Ar
(HR, ESI) for C36H28N3O+ Calcd 518.2227 [M + H]+. Found Ar
518.2229 [M + H]+.
−
−
H), 7.96 (d, 2H, J = 8.8 Hz, Ar
H), 7.44-7.53 (m, 9H, Ar
−
−
(ppm): 160.1 (Cq), 158.9 (Cq), 145.6 (Cq), 145.1 (Cq), 144.5
(Z)-N-(3-(4-((E)-11-azidoundec-1-en-1-yl)phenyl)-5-phenyl-2H- (Cq); 142.1 (Cq), 132.0 (Cq), 131.6 (CH), 131.2 (Cq), 131.0 (CH),
pyrrol-2-ylidene)-3,5-diphenyl-1H-pyrrol-2-amine (8j). Dark 130.9 (CH), 130.7 (Cq), 130.5 (CH), 129.5 (CH), 129.4 (CH),
8 | J. Name., 2012, 00, 1-3
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DOI: 10.1039/C6OB02602H
129.3 (CH), 129.2 (CH), 128.5 (CH), 128.4 (CH), 123.8 (Cq), NMR (200 MHz, CDCl3) δ (ppm): 5.81 (m, 1H), 5.00 (m, 2H),
119.3 (CH), 118.6 (CH). IR cm-1: 1510, 1470, 1452, 1391, 1034, 3.25 (t, 2H, J = 7.0 Hz), 2.05 (m, 2H), 1.59 (m, 2H) and 1.44-1.22
-
1022, 810, 755, 687. m/z (HR, ESI) for C32H21BBrF2N3 Calcd (m, 12H).
575.0980 [M]-. Found 575.1011 [M]-.
N-(4-ethynylphenyl)-4-methylbenzenesulfonamide (9).30 In a
(E)-1-(4-(3-(tert-butoxy)-3-oxoprop-1-en-1-yl)phenyl)-5,5-
difluoro-3,7,9-triphenyl-5H-dipyrrolo[1,2-c:2’,1’-
reaction tube, 3 mL of THF/Et3N (1:1) are degassed for by
bubbling
nitrogen.
Then
N-(4-iodophenyl)-4-
f][1,3,5,2]triazaborinin-4-ium-5-uide (8a’). Dark green metallic methylbenzenesulfonamide (75.0 mg, 0.2 mmol), CuI (4.0 mg,
1
solid, (yield 99%), TLC, Rf = 0.40 (EP/CH2Cl2 1/1, v/v). H NMR 10 mol%), Pd(PPh3)2Cl2 (8 mg, 5 mol%) are charged. After 5
(200 MHz, CDCl3) δ (ppm): 8.02
1H, J = 16.0 Hz, COCH=CH), 7.60 (d, 2H, J = 8.0 Hz, Ar
7.48 7.52 (m, 9H, Ar H), 7.06 (s, 2H, Pyrr H), 6.48 (d, 1H, J = room temperature for 4 hours. The resulting mixture is diluted
−
8.13 (m, 8H, Ar
−
H), 7.64 (d, minutes, ethynyltrimethylsilane (39 mg, 0.4 mmol) is added
−
H) dropwise. The tube is sealed and the black solution is stirred at
−
−
−
16.0 Hz, COCH=CH), 1.58 (s, 9H, CH3). 13C NMR (50.2 MHz, with ethyl acetate and filtered through a silica pad to remove
CDCl3) δ (ppm): 166.0 (Cq), 160.0 (Cq), 158.9 (Cq), 145.6 (Cq), all the catalysts. Evaporation of the solvents affords a brown
145.3 (Cq), 144.4 (Cq), 142.5 (CH), 142.4 (Cq), 135.7 (Cq), 133.7 oil that is dissolved in anhydrous THF. TBAF is added (0.2 mL
(Cq), 132.0 (Cq), 131.3 (Cq), 131.2 (Cq), 130.9 (CH), 130.7 (CH), 1.1 M in THF, 0.22 mmol) and the reaction is stirred to
130.2 (CH), 129.4 (CH), 129.2 (CH), 128.4 (CH), 128.0 (CH), completion. Removal of the solvents afford a brown oil that is
120.8 (CH), 119.3 (CH), 118.7 (CH), 80.5 (Cq), 28.1 (CH3). IR cm- purified by silica gel chromatography using pure
1: 2973, 1702, 1633, 1514, 1475, 1454, 1394, 1143, 1097, 1034, dichloromethane
as
eluent.
N-(4-ethynylphenyl)-4-
-
764, 591. m/z (HR, ESI) for C39H31BF2N3O2 Calcd 623.2556 [M]-. methylbenzenesulfonamide is obtained as off white solid (54.0
Found 623.2593 [M]-. Dark green metallic solid, (yield 91%), mg, yield 99% starting from the aryl iodide). H NMR (200
1
TLC Rf = 0.51 (EP/CH2Cl2 40/60, v/v). H NMR (200 MHz, CDCl3) MHz, CDCl3) δ (ppm): 7.70 (d, 2H, J = 8.6 Hz), 7.35 (dm, 2H, J =
1
δ (ppm): 8.00
7.03 (s, 1H, Pyrr
3.28 (t, 2H, J = 7.0 Hz, CH2N3), 2.26 (q, 2H, J = 6.0 Hz, Click procedure: Synthesis of (E)-5,5-difluoro-1-(4-(11-(4-(4-
CH=CHCH2), 1.32 phenyl)-1H-1,2,3-triazol-1-
1.70 (bs, 14H, 7xCH2). 13C NMR (50.2 MHz, (4-methylphenylsulfonamido)
−
8.12 (m, 8H, Ar
−
H), 7.40−7.56 (m, 11H, Ar−H), 8.6 Hz), 7.24 (d, 2H, J = 8.6 Hz), 7.17 (bs, 1H), 7.05 (d, 2H, J =
−
H), 7.01 (s, 1H, Pyrr
−
H), 6.43 (m, 2H, CH=CH), 8.6 Hz), 3.04 (s, 1H), 2.39 (s, 1H).
−
CDCl3) δ (ppm): 159.8 (Cq), 158.8 (Cq), 145.6 (Cq), 145.2 yl)undec-1-en-1-yl)phenyl)-3,7,9-triphenyl-5H-dipyrrolo[1,2-
(Cq),145.0 (Cq), 143.9 (Cq), 143.6 (Cq), 139.1 (Cq), 133.9 (CH), c:2',1'-f][1,3,5,2]triazaborinin-4-ium-5-uide (10): Following the
132.8 (Cq), 132.3 (Cq), 131.5 (Cq), 131.4 (Cq), 130.7 (CH), 130.6 reported procedure, a solution of N-(4-ethynylphenyl)-4-
(CH), 12.4 (CH), 129.2 (CH), 128.4 (CH), 126.0 (CH), 125.6 (CH), methylbenzene sulfonamide (71 mg, 0.26 mmol) in THF (2 mL)
118.8 (CH), 118.2 (CH), 51.3 (CH2), 33.1 (CH2), 29.2 (CH2), 29.1 is treated with azido-aza-BODIPY (138 mg, 0.20 mmol), CuI (7.0
(CH2), 29.0 (CH2), 28.7 (CH2), 28.5 (CH2). IR cm-1: 3055, 2926, mg, 0.037mmol) and DIPEA (64.0 mg, 0.73 mmol) in a sealed
2851, 2092, 1515, 1475, 1754, 1273, 1127, 762, 748 m/z (HR, tube. The reaction mixture is heated up to 65 °C till
ESI) for C58H54BF2N7O2S+ Calcd 643.3544 [M + H]+. Found completion. Solvent evaporation followed by purification of
643.3546 [M + H]+.
the crude residue by flash column chromatography (CHCl3)
Undec-10-en-1-yl methanesulfonate.28 In a flame dried round affords 192 mg of the triazole. Dark green metallic solid, (yield
bottomed flask, a solution of undec-10-en-1-ol (0.85 g, 5.0 99%), TLC Rf = 0.11 (CHCl3). 1H NMR (200 MHz, CDCl3) δ (ppm):
mmol) and trimethylamine (1.1 mL, 7.5 mmol) in 20 mL of dry 8.00
diethyl ether is cooled to 0°C. Methanesulfonyl chloride (0.86 2H, J = 7.5 Hz, Ar
g, 7.5 mmol) is added dropwise and the resulting suspension is 7.5 Hz, Ar H), 7.12 (d, 2H, J = 7.5 Hz, Ar
stirred at room temperature. After three hours, water is added Pyrr H), 7.00 (s, 1H, Pyrr H), , 6.40 (m, 2H, CH=CH), 4.36 (t,
to quench the reaction and the aqueous phase is extracted 1H, J = 7.0 Hz, Triazole CH2), 2.36 (s, 3H, CH3 tolyl), 2.25 (q, 2H,
with diethyl ether (3x20 mL). The collected ethereal phase is J = 7.0 Hz, CH=CHCH2), 1.93 (m, 2H, Triazole CH2CH2),
washed with brine (2x30 mL) and dried over Na2SO4. Removal 1.25
1.55 (m, 12H, 6XCH2). 13C NMR (50.2 MHz, CDCl3) δ
−
8.11 (m, 8H, Ar
−
H), 7.70 (s, 1H, Ar
−
H, triazole), 7.62 (d,
H), 7.20 (d, 2H, J =
H), 7.05 (s, 1H,
−
H), 7.40
−
7.58 (m, 12H, Ar
−
−
−
−
−
−
−
−
of the solvent affords 1.3 g of the protected alcohol as a pale (ppm): 159.6 (Cq), 158.7 (Cq), 148.8 (Cq), 145.6 (Cq), 145.2
yellow oil that is used with no further purification (yield 100%). (Cq), 143.7 (Cq), 143.5 (Cq), 139.1 (Cq), 136.5 (Cq), 135.9 (Cq),
1H NMR (200 MHz, CDCl3) δ (ppm): 5.80 (m, 1H), 4.96 (m, 2H), 132.8 (CH), 132.2 (Cq), 131.5 (Cq), 131.4 (Cq), 130.7 (CH),
4.21 (t, 2H, J = 6.6 Hz), 3.00 (s, 3H), 2.05 (m, 2H), 1.75 (m, 2H) 130.5 (CH), 129.5 (CH), 129.4 (CH), 129.2 (CH), 128.4 (CH),
and 1.46-1.22 (m, 12H).
127.4 (Cq), 127.1 (CH), 126.4 (CH), 126.0 (CH), 121.6 (CH),
11-azidoundec-1-en:29 undec-10-en-1-yl methanesulfonate 119.4 (CH), 118.8 (CH), 118.3 (CH), 50.2 (CH2), 33.1 (CH2), 30.1
(1.3 g, 5.0 mmol) is dissolved in 5 mL of DMF, NaN3 (0.81 g, (CH2), 29.2 (2XCH2), 29.1 2(2XCH2), 28.8 (CH2), 26.3(CH2), 21.3
12.5 mmol) is added and the suspension strongly stirred (CH3). IR cm-1: 2926, 2850, 1658, 1604, 1503, 1151, 1092, 914
overnight at room temperature. After reaction completion, the C58H54BF2N7O2S+ Calcd 961.9766 [M + H]+. Found 961.9755 [M
resulting mixture is diluted with 50 mL of diethyl ether, + H]+.
washed with brine (7x20 mL) and dried over Na2SO4.
Evaporation of the solvent affords a pale yellow oil that is
Acknowledgements
filtered through a short silica pad using CH2Cl2. 11-azidoundec-
1
1-ene is obtained as a colorless oil (0.98 g, yield 99.5%). H
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DOI: 10.1039/C6OB02602H
ARTICLE
Journal Name
Boron Dipyrromethenes - BODIPY-Based NIR Cyanine-Like
Dyes, Eur. J. Org. Chem., 2012, 1825-1834.
This study stems from the STREAM project, “Strigolactones
enhances Agricultural Methodologies” which is funded as a EU
COST Action-COST FA1206. Part of the work has also been
supported by University of Turin (Project SLEPS, Compagnia di
San Paolo). We acknowledge the Lagrange Project-CRT Foun-
dation/ISI Foundation.
5.
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