Oligomers containing ethynylpyridazine moieties: Synthesis, fluorescence and liquid crystalline properties. Diazines 50

Article abstract of DOI:10.3987/COM-07-11220

Conjugated oligomers with ethynylpyridazine units have been synthetized by Sonogashira and Suzuki cross-coupling reactions. Some of them present interesting liquid crystals properties investigated by differential scanning calorimetry (DSC) and polarized l

Full text of DOI:10.3987/COM-07-11220

HETEROCYCLES, Vol. 75, No. 2, 2008
357
HETEROCYCLES, Vol. 75, No. 2, 2008, pp. 357 - 374. © The Japan Institute of Heterocyclic Chemistry
Received, 12th September, 2007, Accepted, 5th November, 2007, Published online, 9th November, 2007. COM-07-11220
OLIGOMERS CONTAINING ETHYNYLPYRIDAZINE MOIETIES:
SYNTHESIS, FLUORESCENCE AND LIQUID CRYSTALLINE
PROPERTIES. DIAZINES 50
Sylvain Achelle,a Nelly Plé,a* David Kreher,b Fabrice Mathevet,b Alain
Turck,a and André-Jean Attiasb
aL. C. O. F. H. Laboratory, UMR 6014 IRCOF-INSA, BP. 08. 76131
Mont-Saint-Aignan Cedex, France bMacromolecular Chemistry Laboratory, UMR
7610, Pierre et Marie Curie University, tour 44-54 case 185, 4 place Jussieu
75252 Paris Cedex 5, France
E-Mail: nelly.ple@insa-rouen.fr
Abstract – Conjugated oligomers with ethynylpyridazine units have been
synthetized by Sonogashira and Suzuki cross-coupling reactions. Some of them
present interesting liquid crystals properties investigated by differential scanning
calorimetry (DSC) and polarized light microscopy. Some of these oligomers are
fluorescent.
INTRODUCTION
Linear arylethynyl molecules with extended π-conjugation are of considerable research interest due to
their potential applications as molecular wires,1 liquid crystals,2 components of organic light emitting
devices (OLEDs) for displays and lighting,3 field effect transistors (FETs)4 and non-linear optical
materials.5 Incorporation of one π-deficient heterocycle6 such as pyridine,7 1,3,5-triazine,8 pyrimidine,9
pyrazine10 into the backbone of such molecules gives rise to new materials with interesting properties of
electron conductivity and transport compared to their phenylene analogues. On an other way, ferroelectric
liquid crystal mixtures with high biaxiality were obtained with structures which present an high lateral
dipole and a negative dielectric anisotropy (∆ε = ε// − ε⊥ <0) or with high ε⊥.values. Such material can be
achieved by the introduction of lateral, polar groups such as F or CN into the mesogenic molecule.
However laterals substituents such as cyano groups lead to a significant increase in the viscosity.
Incorporation of 3,6-pyridazinyl moities, whose lone pair electrons, located at the nitrogen atoms, form a

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HETEROCYCLES, Vol. 75, No. 2, 2008
dipole orthogonal to the long axis of the polyarylenes, is also an excellent mean to obtain
liquid-crystalline compounds with negative dielectric anisotropy.11 Ethynyl moities added in the
backbone lead to ethynyl aromatic/heteroaromatic systems which are versatile rigid-rod molecules. The
main advantage of them compared to their arylenevinylene counterparts is the lack of possible Z/E
isomerism and their higher stability.12
With the aim to synthesize new conjugated structures containing ethynylaromatic/heteroaromatic moieties,
we report therein the synthesis of a new family of four types of rod-like oligomers including pyridazine
units (Scheme 1):
RO
OR
RO
OR
N N
N N
N N
Type I
Type II
RO
OR
RO
OR
N N
N N
Type III
Type IV
Scheme 1
Such oligomers could present several interesting applications; we report here the liquid crystalline and
photophysical properties of some of them. This study is a part of our work dedicated to take advantages
of diazines as building blocks for the synthesis of organic molecular materials.13
RESULTS AND DISCUSSION
For the synthesis of these alkynylpyridazines, the ethynyl moiety could be introduced using Sonogashira
or Negishi reactions with chloro, triflate and iodo derivatives as starting materials.14 Among these
methods, iodopyridazines were the most efficient and convenient starting materials chosen to react with
trimethylsilylacetylene under modified Sonogashira conditions (Pd[PPh3]2Cl2, CuI, triethylamine in
THF).15 Moreover, due to the π-deficient character of pyridiazine ring, the iodo derivatives can be easily
obtained by nucleophilic substitution of a chlorine atom by iodine starting from commercially available
chloro derivatives.16 Using this methodology, monoalkynylpyridazines 4-6 were obtained with moderate
to good yields from the corresponding monoiodopyridazine 1-3 (Scheme 2):

HETEROCYCLES, Vol. 75, No. 2, 2008
359
X
X
H
X
I
Me3Si
H
Pd(PPh3)2Cl2/CuI
NEt3/THF
N
N
N
N
N
N
KOH/MeOH
rt/15 min
rt/15h
SiMe3
1 X = Ph
2 X = OMe
3 X = NBu2
4 84%
5 52%
6 86%
7 91%
8 91%
9 93%
Scheme 2
Starting from 3,6-diiodopyridazine 10 and using twice Sonogashira coupling reactions, the
dialkynylpyridazines 11-12 were obtained (Scheme 3). In all cases, the deprotection of the trimethylsilyl
17
groups can be easily carried out with potassium hydroxide in methanol
leading to the
ethynylpyridazines which could be used as building blocks for elaboration of various oligomers.
R
H
I
KOH/MeOH
15 min/rt
R
H
N
N
N
N
N
N
Pd(PPh3)2Cl2/CuI
NEt3/THF
I
rt/15h
10
R
H
13 84%
11 R = SiMe3 89%
12 R= C6H13 59%
Scheme 3
The symmetrical oligomers of type I have been achieved by cross-coupling reaction of
4,6-diiodopyridazine 10 with 4-alkoxyphenylacetylene leading to compounds 14-15 (Scheme 4) in
moderate yields. It could be noticed that presence of a long terminal alkoxyl chains should induce
mesogenic properties for compound 15.
RO
H
I
I
RO
OR
N N
N N
Pd(PPh3)2Cl2/ CuI
NEt3/THF/rt/ 15h
10
14 R = Me
71%
15 R = C12H25 63%
Scheme 4

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HETEROCYCLES, Vol. 75, No. 2, 2008
Symmetrical oligomers of type II are based on a moiety showing the successive sequence
pyridazine-ethynyl-pyridazine. The Scheme 5 shows that the synthesis of such oligomers requires a
succession of Suzuki and Sonogashira cross-coupling reactions as well as deprotection of terminal alkyne
bearing trimethylsilyl groups.
OR
OR
I
I
p-ROC6H4B(OH)2
TMSA
N
N
N
N
N
N
Pd(PPh3)2Cl2/CuI
NEt3/THF
8h/rt
Pd(PPh3)4/Cs2CO3
toluene/H2O
24h/∆
I
10
16 R = Me
46%
SiMe3
17 R = C8H17 32%
18 R = Me
73%
OR
19 R = C8H17 46%
OR
KOH/MeOH
15 min/RT
N
N
N
N
Pd(PPh3)2Cl2/CuI
NEt3/THF
8h/rt
N
N
H
20 R = Me
95%
21 R = C8H17 91%
OR
22 R = Me
83%
23 R = C8H17 64%
Scheme 5
The first step leads to the iodo derivatives 16 and 17 which are the key intermediates of this synthetic
route.
These compounds were obtained by reaction of one equivalent of 4-substitued phenylboronic acid with
the 4,6-diiodopyridazine 10 with moderate yields due to the low stability of the iodo derivatives under
standard aqueous Suzuki cross coupling conditions. To improve the global yield, other synthetic routes
have been tested to access to compounds 16 and 17 but are kept unsuccessful. Indeed, products 16 and 17
cannot be obtained by halogen exchange using chloro derivatives as starting materials and hydriodic acid
since cleavage of the alkoxy groups is observed. The use of bromo derivatives could be an alternative

HETEROCYCLES, Vol. 75, No. 2, 2008
361
solution, but when they are used to react under cross coupling reaction, only dicoupled products are
obtained. In the second step, compounds 16 and 17 were then coupled to trimethylsilylacetylene to afford
18, 19 in acceptable yields. The deprotection of terminal alkyne by alcoholic potassium hydroxide led to
20 and 21 in good yields. A further Sonogashira cross coupling reaction with compounds 16 and 17
provided the final expected oligomers 22 and 23, which were obtained in four steps starting from
4,6-diiodopyridazine respectively with a global yield of 26 % and 9 %.
The unsymmetrical oligomer 27 was obtained by a Suzuki cross coupling reaction of
2-alkoxy-6-chloropyridazine 26 with the elaborated phenylboronic acid 25. This one resulted from a
Sonogashira coupling reaction between 1-decyloxy-4-iodobenzene and 4-bromophenylacetylene, leading
to bromo derivative 24. A further halogen-metal exchange followed by reaction with triisopropyl borate
as electrophile afforded the expected boronic acid 25. The intermediate compound 26 resulted from a
mono nucleophilic substitution of one chlorine atom of the commercial 4,6-dichloropyridazine with
lithium dodecylate (Scheme 6):
Br
B(OH)2
OC10H21
Br
H
Pd(PPh3)2Cl2/CuI
THF/NEt3/ 8h/rt
1. nBuLi/THF/-78°C
2. B(OiPr)3
3. HCl
I
81%
66%
OC10H21
OC10H21
24
25
OC10H21
Cl
Cl
LiOC12H25
THF/∆/15h
25
N
N
N
N
Pd(PPh3)4 /Cs2CO3
toluene /H2O/∆/40h
89%
Cl
OC12H25
N
N
70%
26
OC12H25
27
Scheme 6

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HETEROCYCLES, Vol. 75, No. 2, 2008
The synthesis of oligomer 30 was carried out in three steps starting from 4,6-diiodopyridazine 10. The
first step was a nucleophilic substitution of an iodine atom by lithium octylate, followed by a Sonogashira
cross coupling reaction with 4-bromophenylacetylene affording to bromo derivative 29. In the last step, a
Suzuki coupling reaction of 29 with 4-decyloxyphenylboronic acid provided the oligomer 30 with a
global yield of 60 % starting from 10 (Scheme 7):
OC8H17
I
OC8H17
N
N
LiOC8H17
Br
H
N
N
THF/∆/15h
N
N
87%
Pd(PPh3)2Cl2/ CuI
NEt3 /THF/rt/ 8h
82%
I
I
10
28
Br
29
p-C10H21OC6H4B(OH)2
Pd(PPh3)4/Cs2CO3
toluene/H2O
∆/30h
C10H21O
OC8H17
N N
84%
30
Scheme 7
To investigate the assumed liquid crystalline properties of the oligomers, their melting behavior was
examined by differential scanning calorimetry (DSC) and polarized-light optical microscopy. The
oligomer 15 (Type I) showed a liquid crystalline mesophase, identified as smectic by the typical focal
conic texture from the melting peak at 133.2 °C (∆H = 14.75 kJ/mol) to the clearing temperature
determinated for 208.2 °C (∆H = 4.83 kJ/mol) during the heating run, while during the cooling run
revealed the clearing peak at 194.8 °C (∆H = 2.02 kJ/mol) and the crystallisation peak at 114.2 °C (∆H =
8.92 kJ/mol). Polarization microscopy revealed no liquid crystalline behavior for oligomer 23 (Type II).
Compound 27 (Type III) showed liquid crystalline properties with two differents mesophases. The first
mesophase consists in a smectic phase between the melting peak at 81.9 °C (∆H = 10.13 kJ/mol) and the
pic corresponding to a smectic/nematic transition observed at 110.0 °C (∆H = 4.97 kJ/mol) during the
heating run (the peaks were observed respectively at 77.5 °C (∆H = 11.93 kJ/mol) and 103.0 °C (∆H =

HETEROCYCLES, Vol. 75, No. 2, 2008
363
4.29 kJ/mol)). The second mesophase is a nematic phase observed until the clearing peak at 178.0 °C (∆H
= 2.81 kJ/mol) during the heating run (169.3 °C (∆H = 2.26 kJ/mol) during the cooling run). The
transition temperatures and the mesophases for compounds 15, 27 are summarized in Table 1:
Table 1. Phase transition temperatures (data in parentheses are phase-transition temperature on cooling)
Oligomer
Mesophase
15
27
C 133.2 (114.2) Sm 208.2 (194.8) I
C 81.9 (77.5) Sm 110.0 (103.0) N 178.0 (169.3) I
absorption spectra in chloroform at 25°C
emission spectra in chloroform at 25°C (excitation at
absorption maxima)
Absorbance
fluorescence
15
23
27
30
1,2000
(au)
50,00
45,00
40,00
35,00
30,00
25,00
20,00
15,00
10,00
5,00
1,0000
0,8000
0,6000
0,4000
0,2000
27
30
0,0000
260
(nm)
λ
(nm)
λ
0,00
360
460
560
300
350
400
450
500
550
600
Figure 1
Table 2. Absorption and emission properties
U.V. Visible Fluorescence
Stokes
Shift
ε (M-1.cm-1)
λemmax
φF
Oligomers
λabsmax (nm)
(nm)
(nm)
15
285, 303
323, 345
294
25997, 29490
35768, 36829
30013
-
-
-
-
23
27
30
-
-
318
24505
422
413
0.05a
0.03a
104
104
309
25672
a
sample excited at 299 nm, quantum yield determinated using 2-aminopyridine in H2SO4 0,1M : (φF =
0.60) as standard.18
The UV absorption and fluorescence emission spectra in chloroform of 15, 23, 27 and 30 are given in
Figure 1 and Table 2. The absorption spectrum of compound 15 in chloroform show well-resolved

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HETEROCYCLES, Vol. 75, No. 2, 2008
vibronic structures with four maxima in U. V. (285, 303, 323, 345nm) which infer the rigidity of the core
structure. Compounds 15 and 23 do not show any fluorescence properties, it could be explained by a low
conjugation into the pyridazine ring. On the other hand, the unsymmetrical compounds 27 and 30 are
slightly fluorescent with emission maximum in violet. Their relative fluorescence quantum yields (φF) are
situated between 0.03 and 0.05.
CONCLUSION
In summary, using Sonogashira and Suzuki cross-coupling reactions, we have synthesized various
conjugated oligomers with ethynylpyridazine units. Some of them present interesting fluorescent
properties and/or liquid crystals properties which are investigated by differential scanning calorimetry
(DSC) and polarized light microscopy.
EXPERIMENTAL
1
13
Melting points were determined on a Electrothermal 1100 instrument. The H and C nmr spectra were
recorded on a Bruker AC 300 (300 MHz 1H, 75 MHz 13C, 282.5 MHz 19F) instrument. Microanalyses
were performed on a Carlo Erba CHNOS 1160 apparatus. The IR spectra were obtained as potassium
bromide pellets with a Perkin-Elmer 16 PC FT-IR spectrometer. Mass spectra were recorded on an
ATI-Unicam Automass® apparatus. UV-Visible spectra were obtained on a Varian Can 50 scan
spectrophotometer. Fluorescence spectroscopic studies were performed in a semi-micro fluorescence cell
(Hellma®, 104F-QS, 10 x 4 mm, 1400 µL) with a Varian Cary Eclipse spectrophotometer.
General procedure A for cross coupling reaction under Suzuki conditions: A mixture of halogenoaryl,
arylboronic acid, tetrakis(triphenylphosphine)palladium(0) (0.05 equiv. per coupling reaction), cesium
carbonate (1 equiv. per coupling reaction), aqueous 2M potassium carbonate (1 equiv. per coupling
reaction.) and ethanol (1.5 mL) in degassed toluene (20 mL) was heated to reflux under nitrogen for 30 h.
The reaction mixture was cooled, diluted with 20 mL of a mixture of water and EtOAc (1:1) and the
organic layer separated. The aqueous layer was extracted with EtOAc (3 x 20 mL). The combined organic
extracts were dried over magnesium sulfate and evaporated.
General procedure B for cross coupling reaction under Sonogashira conditions: To iodoaryl in 5 mL
of THF was added alcyne, 0.5 mL of NEt3, 3 % mol (per coupling reaction) of CuI and 3 % mol (per
coupling reaction) of Pd(PPh3)2Cl2. The suspension was stirred at rt for 8h. The reaction mixture was
cooled, diluted with 20 mL of a mixture of water and CH2Cl2 (1:1) and the organic layer separated. The

HETEROCYCLES, Vol. 75, No. 2, 2008
365
aqueous layer was extracted with CH2Cl2 (2 x 20 mL). The combined organic extracts were dried over
magnesium sulfate, filtered and evaporated.
General procedure C for trimethylsilyl groups deprotection: A mixture of arylethynyltrimethylsilane
and a solution of potassium hydroxide in MeOH (1M, 10 mL) was stirred at rt for 15 min, Then the
solution was neutralized with 1M aqueous HCl and extracted with CH2Cl2 (3 x 20 mL) The combined
organic extracts were dried over magnesium sulfate, filtered and evaporated.
3-Phenyl-6-(trimethylsilylethynyl)pyridazine (4): Sonogashira cross-coupling reaction of
3-iodo-6-phenylpyridazine (400 mg, 1.42 mmol) with ethynyltrimethylsilane (404 µL, 2.84 mmol)
according to the general procedure B gave after purification by column chromatography (silica gel, eluent
petroleum ether : EtOAc (90:10)) 300 mg (84 %) of 4 as a beige solid. mp 138 °C. 1H NMR (CDCl3) : δ
0.32 (s, 9H, Si(Me)3), 7.52 (m, 3H, HPh), 7.62 (d, 1H, J = 8.7 Hz, H5), 7.82 (d, 1H, J = 8.7 Hz, H4), 8.09
13
(m, 2H, HPh) C (CDCl3) : δ 0.0, 101.1, 101.2, 123.4, 127.6, 129.5, 130.6, 130.8, 136.1, 146.5, 157.5
IR : 2170, 1540, 1450, 1396, 1277, 1250, 864, 840, 748, 688 cm-1 Anal. Calcd for C15H16N2Si (252.11):
C, 71.38 H, 6.39 N, 11.10. Found: C, 71.45 H, 6.31 N, 11.00.
3-Methoxy-6-(trimethylsilylethynyl)pyridazine (5): Sonogashira cross-coupling reaction of
3-iodo-6-methoxypyridazine (334 mg, 1.42 mmol) with ethynyltrimethylsilane (404 µL, 2.84 mmol)
according to the general procedure B gave after purification by column chromatography (silica gel, eluent
CH2Cl2) 152 mg (52 %) of 5 as a brown solid. mp 72 °C. 1H NMR (CDCl3) : δ 0.30 (s, 9H, Si(Me)3), 4.16
(s, 3H, OMe), 6.92 (d, 1H, J = 9.0 Hz, H5), 7.46 (d, 1H, J = 8.7 Hz, H4) 13C (CDCl3) : δ 0.0, 55.5, 60.8,
100.9, 116.8, 132.8, 143.7, 163.8 IR : 2168, 1591, 1542, 1461, 1406, 1329, 1292, 15252, 1011, 865,
814 cm-1 Anal. Calcd for C10H14N2OSi (206.09): C, 58.21 H, 6.84 N, 13.58. Found: C, 57.89 H, 6.61 N,
13.32.
3-Dibutylamino-6-(trimethylsilylethynyl)pyridazine (6): Sonogashira cross-coupling reaction of
3-dibutylamino-6-iodopyridazine (600 mg, 1.8 mmol) with ethynyltrimethylsilane (384 µL, 2.7 mmol)
according to the general procedure B gave after purification by column chromatography (silica gel, eluent
1
petroleum ether : EtOAc (8:2)) 469 mg (86 %) of 6 as a colorless oil. H NMR (CDCl3) : δ 0.23 (s, 9H,
Si(Me)3), 0.92 (t, J = 7.3 Hz, 6H, 2 x Me), 1.36-1.28 (m, 4H, 2 x CH2), 1.59-1.54 (m, 4H, 2 x CH2), 3.48
(t, J = 7.7 Hz, 4H, N(CH2)2), 6.46 (d, J = 9.4 Hz, 1H, H4), 7.18 (d, J = 9.4 Hz, 1H, H5) 13C (CDCl3) : δ 0.0,
14.1, 20.4, 29.7, 48.9, 95.8, 102.5, 109.6, 130.3, 137.2, 156.7 IR : 691, 758, 860, 1067, 1290, 1341, 1413,

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HETEROCYCLES, Vol. 75, No. 2, 2008
1465, 1542, 1587, 2227 cm-1 Anal. Calcd for C17H29N3Si (303.21): C, 67.27 H, 9.63 N, 13.84. Found: C,
67.23 H, 9.70 N, 13.85.
3-Ethynyl-6-phenylpyridazine (7): Trimethylsilyl deprotection reaction of 4 (100 mg, 0.40 mmol)
according to the general procedure C (reaction time: 15 min) gave 66 mg (91 %) of 7 as a brown solid.
mp 118 °C. 1H NMR (CDCl3) : δ 3.48 (s, 1H, H2’), 7.56-7.53 (m, 3H, HPh), 7.67 (d, J = 9.4 Hz, 1H, H4),
7.86 (d, J = 9.4 Hz, 1H, H5), 8.13-8.10 (m, 2H, HPh). 13C (CDCl3) : δ 80.6, 82.4, 123.4, 127.6, 129.5,
130.7, 130.9, 136.0, 145.9, 158.0 IR : 3294, 2118, 1449, 1401, 1115, 1013, 866, 746, 690, 633 cm-1 Anal.
Calcd for C12H8N2 (180.07) : C, 79.98 H, 4.47 N, 15.55. Found: C, 79.90 H, 4.42 N, 15.48.
3-Ethynyl-6-methoxypyridazine (8): Trimethylsilyl deprotection reaction of 5 (151 mg, 1.12 mmol)
according to the general procedure C (reaction time: 15 min) gave after purification by column
1
chromatography (silica gel, eluent CH2Cl2) 66 mg (91 %) of 8 as a brown solid. mp <50 °C. H NMR
(CDCl3) : δ 3.31 (s, 1H, H2’), 4.16 (s, 3H, OMe), 6.94 (d, J = 9.4 Hz, 1H, H4), 7.47(d, J = 9.4 Hz, 1H, H5)
13C (CDCl3) : δ 54.1, 79.2, 95.7, 115.6, 131.5, 141.6, 162.7 IR : 3276, 2115, 1587, 1460, 1406, 1327,
1290, 1099, 1010, 857, 717, 648 cm-1 Anal. Calcd for C7H6N2O (134.05): C, 62.68 H, 4.51 N, 20.88.
Found: C, 62.35 H, 4.74 N, 20.71.
6-Dibutylamino-3-ethynylpyridazine (9): Trimethylsilyl deprotection reaction of 6 (450 mg, 1.48
mmol) according to the general procedure C (reaction time: 15 min) gave 318 mg (93 %) of 9 as a yellow
oil. 1H NMR (CDCl3) : δ 0.90 (t, J = 7.3 Hz, 6H, 2 x Me), 1.34-1.27 (m, 4H, 2 x CH2), 1.57-1.51 (m, 4H,
2 x CH2), 3.18 (s, 1H, H2’), 3.47 (t, J = 7.7 Hz, 4H, N(CH2)2), 6.61 (d, J = 9.4 Hz, 1H, H4), 7.20 (d, J =
9.4 Hz, 1H, H5) 13C (CDCl3) : δ 14.3, 20.5, 30.0, 49.1, 78.8, 81.5, 110.3, 130.9, 136.5, 157.0 IR : 3310,
2958, 2931, 2872, 2110, 1588, 1544, 1487, 1455, 1428, 1373, 1179 cm-1 Anal. Calcd for C14H21N3
(231.17): C, 72.69 H, 9.15 N, 18.16. Found: C, 72.44 H, 9.02 N, 18.03.
3,6-Bis(trimethylsilanylethynyl)pyridazine (11): Sonogashira cross-coupling reaction of 4,6-
diiodopyridazine (250 mg, 0.8 mmol) with Ethynyltrimethylsilane (196 mg, 2.0 mmol) according to the
general procedure B gave after purification by column chromatography (silica gel, eluent CH2Cl2) 182
mg (94 %) of 11 as a brown solid. mp 124 °C. 1H NMR (CDCl3) : δ 0.28 (s, 18H, Si(Me)3), 7.50 (s, 2H,
H4,5) 13C (CDCl3) : δ 0.0, 100.9, 102.8, 129.5, 146.0 IR : 2958, 171, 1528, 1389, 1255, 847, 762 cm-1 Anal.
Calcd for C14H20N2Si2 (272.12): C, 61.71 H, 7.40 N, 10.28. Found: C, 61.40 H, 7.25 N, 10.25.

HETEROCYCLES, Vol. 75, No. 2, 2008
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3,6-Di(oct-1-ynyl)pyridazine (12): Sonogashira cross-coupling reaction of 4,6-diiodopyridazine (200 mg,
0.6 mmol) with oct-1-yne (165 mg, 1.5 mmol) according to the general procedure B gave after
purification by column chromatography (silica gel, eluent CH2Cl2) 99 mg (56 %) of 12 as a brown solid.
mp < 50 °C. 1H NMR (CDCl3) : δ 0.90 (t, J = 6.8 Hz, 6H, Me), 1.68-1.25 (m, 16H, 8 x CH2), 2.49 (t, J =
7.1 Hz, 4H, 2 x CH2), 7.39 (s, 2H, H4,5) 13C (CDCl3) : δ 14.4, 20.0, 22.9, 28.5, 29.0, 31.7, 78.1, 98.0,
129.0, 146.3 IR : 2955, 2931, 2857, 2233, 1528, 1468, 1399, 1283, 872 cm-1 Anal. Calcd for C20H28N2
(293.23): C, 81.03 H, 9.52 N, 9.45. Found: C, 80.65 H, 9.30 N, 9.08.
3,6-Diethynylpyridazine (13): Trimethylsilyl deprotection reaction of 11 (150 mg, 0.55 mmol) according
to the general procedure C (reaction time: 15 min) gave gave after purification by column
1
chromatography (silica gel, eluent CH2Cl2) 59 mg (84 %) of 13 as a brown solid. mp 80 °C. H NMR
(CDCl3) : δ 3.54 (s, 2H, H2’), 7.59 (s, 2H, H4,5) 13C (CDCl3) : δ 80.0, 84.1, 129.6, 145.8 IR : 3401, 3238,
3161, 2924, 2118, 1528, 1408, 1246, 1107, 849, 760, 714, 525, 481 cm-1 Anal. Calcd for C8H4N2
(128.04): C, 74.99 H, 3.15 N, 21.86. Found: C, 74.85 H, 3.33 N, 21.69.
3,6-Bis-(4-methoxyphenylethynyl)pyridazine (14): Sonogashira cross-coupling reaction of 4,6-
diiodopyridazine (298 mg, 0.9 mmol) with 1-ethynyl-4-methoxybenzene (300 mg, 2.27 mmol) according
to the general procedure B gave after purification by column chromatography (silica gel, eluent EtOAc :
petroleum ether (1:9)) 217 mg (71 %) of 14 as a beige solid. mp 189 °C. 1H NMR (CDCl3) : δ 3.84 (s, 6H,
2 x OMe), 6.91 (d, J = 8.7 Hz, 4H, HPh), 7.56 (s, 2H, H4,5), 7.58 (d, J = 8.7 Hz, 4H, HPh). 13C (CDCl3) : δ
55.8, 85.5, 96.3, 113.8, 114.6, 129.0, 134.3, 146.2, 161.1 IR : 2216, 1603, 1531, 1516, 1504, 1396, 1291,
1249, 1161, 1029, 835 cm-1 Anal. Calcd for C22H16N2O2 (340.12): C, 77.63 H, 4.74 N, 8.23. Found: C,
77.35 H, 4.89 N, 8.05.
3,6-Bis-(4-dodecyloxyphenylethynyl)-pyridazine (15): Sonogashira cross-coupling reaction of 4,6-
diiodopyridazine (298 mg, 0.9 mmol) with 1-dodecyloxy-4-ethynylbenzene (772 mg, 2.70 mmol)
according to the general procedure B gave after purification by column chromatography (silica gel, eluent
1
EtOAc : petroleum ether (1:9)) and recrystalisation in ethanol 368 mg (63 %) of 15 as a beige solid. H
NMR (CDCl3) : δ 0.89 (t, 6H, J = 6.8 Hz, 2 x Me), 1.48-1.29 (m, 36H, 18 x CH2), 1.83-176 (m, 4H, J =
6.8 Hz, 2 x OCH2CH2), 3.95 (t, 4H, J = 6.8 Hz, 2 x OCH2), 6.90 (d, J = 8.6 Hz, 2H, HPh), 7.58-7.55 (m,
13
3H, HPh) C (CDCl3) : δ 14.5, 23.1, 26.1, 26.4, 29.5, 29.8 (2C), 29.9, 30.0 (2C), 32.3, 68.5, 85.5, 96.4,
113.5, 115.1, 128.9, 134.2, 146.2, 160.7 IR : 2921, 2851, 2212, 1604, 1415, 1470, 1404, 1288, 1250,

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1162, 830 cm-1 Anal. Calcd for C44H60N2O2 (648.47): C, 81.43 H, 9.32 N, 4.32. Found: C, 81.14 H, 9.51
N, 4.01.
3-Iodo-6-(4-methoxyphenyl)pyridazine (16): Suzuki cross-coupling reaction of 4,6-diiodopyridazine
(873 mg, 2.63 mmol) with 4-methoxyphenylboronic acid (400 mg, 2.63 mmol) according to the general
procedure A (t = 15 h) gave after purification by column chromatography (silica gel, eluent CH2Cl2) 377
mg (46 %) of 16 as an orange solid. mp 208 °C. 1H NMR (DMSO-d6) : δ 3.86 (s, 3H, OMe), 7.13 (d, J =
9.1 Hz, 2H, HPh), 7.95 (d, J = 9.0 Hz, 1H, H4), 8.12 (d, J = 9.1 Hz, 2H, HPh), 8.18 (d, J = 9.0Hz, 1H, H5)
13C (DMSO-d6) : δ 55.7, 114.9, 125.1, 125.4, 127.6, 128.6, 137.8, 157.7, 161.6 IR : 1606, 1505, 1394,
1298, 1250, 1182, 1030, 835, 822, 744, 561 cm-1 MS (IE) m/z: 312 (M+, 100), 313 (M+, 11) Anal. Calcd
for C11H9IN2O (311.98): C, 42.33 H, 2.91 N, 8.98. Found: C, 42.48 H, 2.89 N, 8.87.
3-Iodo-6-(4-octyloxyphenyl)pyridazine (17): Suzuki cross-coupling reaction of 4,6-diiodopyridazine
(1.50 g, 4.52 mmol) with 4-octyloxyphenylboronic acid (1.13 g, 4.52 mmol) according to the general
procedure A (t = 15 h) gave after purification by column chromatography (silica gel, eluent CH2Cl2) and
1
recrystallisation in methylcyclohexane 592 mg (32 %) of 17 as an ivory solid. mp 159 °C. H NMR
(CDCl3) : δ 0.90 (t, J = 6.8 Hz, 3H, Me), 1.48-1.30 (m, 10H, 5 x CH2), 1.85-1.80 (m, 2H, CH2), 4.03 (t, J
= 6.4 Hz, 2H, OCH2), 7.01 (d, J = 8.7 Hz, 2H, HPh), 7.49 (d, J = 9.0 Hz, 1H, H4), 7.84 (d, J = 9.0 Hz, 1H,
H5), 8.00 (d, J = 8.7 Hz, 2H, HPh) 13C (CDCl3) : δ 14.5, 23.1, 26.4, 29.4, 29.6, 29.8, 32.2, 68.6, 115.4,
122.9, 124.7, 127.6, 128.9, 137.6, 158.5, 161.7 IR : 2955, 2921, 2853, 1608, 1394, 1262, 1183, 835, 828
cm-1 Anal. Calcd for C18H23IN2O (410.09): C, 52.69 H, 5.65 N, 6.83. Found: C, 52.33 H, 5.41 N, 6.61.
3-(4-Methoxyphenyl)-6-(trimethylsilylethynyl)pyridazine (18): Sonogashira cross-coupling reaction of
16 (155 mg, 0.55 mmol) with ethynyltrimethylsilane (142 µL, 1.0 mmol) according to the general
procedure B gave after purification by column chromatography (silica gel, eluent: CH2Cl2) 102 mg
(73 %) of 18 as a yellow solid. mp 146 °C. 1H NMR (CDCl3) : δ 0.32 (s, 9H, Si(Me)3), 3.88 (s, 3H, OMe),
7.03 (d, J = 8.7 Hz, 2H, HPh), 7.56 (d, J = 9.0 Hz, 1H, H4), 7.74 (d, J = 9.0 Hz, 1H, H5), 8.07 (d, J = 8.7
Hz, 2H, HPh) 13C (CDCl3) : δ 0.0, 55.8, 100.5, 101.4, 114.8, 122.4, 128.5, 129.0, 130.4, 145.9, 157.0,
161.9 IR: 2167, 1610, 1510, 1397, 1253, 1183, 1034, 867, 829, 761 cm-1 Anal. Calcd for C16H18N2OSi
(282.12): C, 68.05 H, 6.42 N, 9.92. Found: C, 68.02 H, 6.39 N, 9.93.
3-(4-Octyloxyphenyl)-6-(trimethylsilylethynyl)pyridazine (19): Sonogashira cross-coupling reaction of
17 (355 mg, 0.87 mmol) with ethynyltrimethylsilane (240 µL, 1.73 mmol) according to the general
procedure B gave after purification by column chromatography (silica gel, eluent: CH2Cl2) 194 mg (59 %) of

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369
19 as a brown solid. mp 93 °C. 1H NMR (CDCl3) : δ 0.29 (s, 9H, Si(Me)3), 0.90 (t, J = 6.8 Hz, 3H, Me),
1.48-1.30 (m, 10H, 5 x CH2), 1.84-1.79 (m, 2H, CH2), 4.01 (t, J = 6.4 Hz, 2H, OCH2), 7.01 (d, J = 8.7 Hz,
2H, HPh), 7.54 (d, J = 9.0 Hz, 1H, H4), 7.73 (d, J = 9.0 Hz, 1H, H5), 8.03 (d, J = 8.7 Hz, 2H, HPh) 13C
(CDCl3) : δ 0.0, 14.4, 22.7, 26.1, 29.3 (2C), 29.4, 31.9, 54.7, 99.6, 101.7, 115.2, 122.8, 127.9, 128.8,
130.6, 145.4, 156.8, 161.3 IR : 3428, 2252, 1651, 1249, 1025, 1004, 821, 761 cm-1 Anal. Calcd for
C23H32N2OSi (380.23): C, 72.58 H, 8.47 N, 7.36. Found: C, 72.41 H, 8.34 N, 7.28.
3-Ethynyl-6-(4-methoxyphenyl)pyridazine (20): Trimethylsilyl deprotection reaction of 18 (80 mg,
0.28 mmol) according to the general procedure C (reaction time: 15 min) gave 57 mg (95 %) of 20 as a
brown solid. mp 158 °C. 1H NMR (CDCl3) : δ 3.44 (s, 1H, H2’), 3.88 (s, 3H, OMe), 7.04 (d, J = 8.7 Hz,
2H, HPh), 7.60 (d, J = 9.0 Hz, 1H, H4), 7.67 (d, J = 9.0 Hz, 1H, H5), 8.06 (d, J = 8.7 Hz, 2H, HPh) 13C
(CDCl3) : δ 55.8, 81.2, 82.1, 114.9, 122.5, 128.4, 129.0, 130.6, 145.3, 157.5, 162.0 IR : 3267, 2115, 1607,
1574, 1510, 1425, 1394, 1274, 1251, 1188, 1032, 829, 663 cm-1 Anal. Calcd for C13H10N2O (210.08): C,
74.27 H, 4.79 N, 13.32. Found: C, 74.42 H, 4.46 N, 12.99.
3-Ethynyl-6-(4-octyloxyphenyl) pyridazine (21): Trimethylsilyl deprotection reaction of 19 (152 mg,
0.40 mmol) according to the general procedure C (reaction time: 15 min) gave 112 mg (91 %) of 21 as a
beige solid. mp 117 °C. 1H NMR (CDCl3) : δ 0.90 (t, J = 6.8 Hz, 3H, Me), 1.48-1.30 (m, 10H, 5 x CH2),
1.84-1.79 (m, 2H, CH2), 3.48 (s, 1H, H2’), 4.01 (t, J = 6.4 Hz, 2H, OCH2), 7.03 (d, J = 8.7 Hz, 2H, HPh),
7.58 (d, J = 9.0 Hz, 1H, H4), 7.74 (d, J = 9.0 Hz, 1H, H5), 8.05 (d, J = 8.7 Hz, 2H, HPh) 13C (CDCl3) : δ
14.5, 23.0, 26.4, 29.5, 29.6, 29.7, 32.2, 68.6, 80.3, 82.2, 115.4, 122.6, 128.0, 129.0, 130.6, 145.2, 157.6,
161.6 IR : 3294, 2955, 2920, 2853, 2116, 1609, 1511, 1400, 1255, 1001, 837, 823 cm-1 Anal. Calcd for
C20H24N2O (308.19): C, 77.89 H, 7.84 N, 9.08. Found: C, 77.74 H, 7.71 N, 9.18.
6,6'-Bis-(4-methoxyphenyl)[3,3']bipyridazinylacetylene (22): Sonogashira cross-coupling reaction of
16 (72 mg, 0.23 mmol) with 20 (72 mg, 0.30 mmol) according to the general procedure B gave after
purification by column chromatography (silica gel, eluent CH2Cl2) 75 mg (83 %) of 22 as a beige solid.
mp 152 °C. 1H NMR (CDCl3) : δ 3.90 (s, 6H, 2 x OMe), 7.06 (d, J = 8.7 Hz, 4H, HPh), 7.53 (d, J = 9.0 Hz,
2H, H4), 7.78 (d, J = 9.0 Hz, 2H, H5), 8.02 (d, J = 8.7 Hz, 4H, HPh) 13C (CDCl3) : δ 54.4, 77.4, 113.5,
121.5, 123.2, 126.5, 127.3, 136.2, 157.0, 160.7 IR : 2961, 2928, 1731, 1608, 1510, 1400, 1299, 1258,
1182, 823 cm-1 Anal. Calcd for C24H18N4O2 (394.14): C, 73.08 H, 4.60 N, 14.20. Found: C, 73.39 H, 4.41
N, 13.88.

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6,6'-Bis(4-octyloxyphenyl)[3,3']bipyridazinylacetylene (23): Sonogashira cross-coupling reaction of 17
(231 mg, 0.56 mmol) with 21 (115 mg, 0.37 mmol) according to the general procedure E gave after
purification by column chromatography (silica gel, eluent CH2Cl2) 140 mg (64 %) of 23 as a beige solid.
mp 160 °C. 1H NMR (CDCl3) : δ 0.90 (t, J = 6.8 Hz, 6H, 2 x Me), 1.48-1.30 (m, 20H, 10 x CH2),
1.85-1.80 (m, 4H, 2 x CH2), 4.03 (t, J = 6.4 Hz, 4H, 2 x OCH2), 7.02 (d, J = 8.7 Hz, 4H, HPh), 7.48 (d, J =
13
9.0 Hz, 2H, H4), 7.84 (d, J = 9.0 Hz, 2H, H5), 8.00 (d, J = 8.7 Hz, 4H, HPh) C (CDCl3) : δ 14.5, 23.1,
26.4, 29.6 (2C), 29.7, 32.2, 68.6, 77.4, 115.4, 122.9, 124.6, 127.6, 128.7, 137.6, 158.5, 161.7 IR : 2955,
2922, 2854, 1609, 1394, 1262, 1183, 835, 820 cm-1 Anal. Calcd for C38H46N4O2 (590.36): C, 77.25 H,
7.85 N, 9.48. Found: C, 76.97 H, 7.99 N, 9.63.
1-Decyloxy-4-(4-bromophenylethynyl)benzene (24): Sonogashira cross-coupling reaction of
1-decyloxy-4-iodobenzene (1.47 g, 4.08 mmol) with 1-bromo-4-ethynylbenzene (1.05 g, 5.83 mmol)
according to the general procedure B gave after purification by column chromatography (silica gel, eluent
petroleum ether:EtOAc (9:1)) 1.36 g (81 %) of 24 as a pale yellow solid. mp 82 °C. 1H NMR (CDCl3) : δ
0.90 (t, 3H, J = 6.8 Hz, Me), 1.46-1.28 (m, 14H, 7 x CH2), 1.81-1.68 (m, 2H, J = 6.8 Hz, OCH2CH2), 3.98
(t, 2H, J = 6.8 Hz, OCH2), 6.86 (d, 2H, J = 9.0 Hz, HPh), 7.38 (d, 2H, J = 9.0 Hz, HPh), 7.45 (d, 2H, J =
9.0 Hz, HPh), 7.48 (d, 2H, J = 9.0 Hz, HPh) 13C (CDCl3) : δ 14.5, 23.1, 26.4, 29.6 (2C), 29.7, 29.8, 29.9,
30.0, 68.5, 87.3, 91.1, 114.9, 115.0, 122.4, 123.0, 131.9, 133.2, 133.4, 159.8 IR: 2919, 2850, 2216, 1606,
1511, 1287, 1253, 1089, 840, 824 cm-1 Anal. Calcd for C24H29BrO (412.14): C, 69.73 H, 7.07. Found: C,
63.64 H, 6.96.
4-(4-Decyloxyphenylethynyl) phenylboronic acid (25): To a solution of 24 (1.55 g, 3.78 mmol) in
anhydrous THF (100 mL) under nitrogen at –78 °C was added n-BuLi (1.6 M in hexanes, 1.2 equiv.)
dropwise. The reaction mixture was stirred at –78 °C for 30 min then triisopropyl borate (3 equiv.) was
added dropwise, the reaction mixture was stirred again for 30 min at –78 °C and allowed to to warm to
20 °C with stirring overnight. The reaction was quenched with a mixture of THF : HCl : EtOH (8:2:2),
neutralized with aqueous saturated NaHCO3, diluted with 50 mL of a mixture of water and Et2O (1:1) and
the organic layer separated. The aqueous layer was extracted with Et2O (2 x 50 mL). The combined
organic extracts were dried over magnesium sulfate and evaporated. If necessary, the product is purified
by washing with CH2Cl2 to give 944 g (66 %) of 25 as a yelow solid. mp 98 °C. 1H NMR (DMSO-d6) : δ
0.86 (t, 3H, J = 6.8 Hz, Me), 1.41-1.26 (m, 14H, 7 x CH2), 1.74-1.70 (m, 2H, J = 6.8 Hz, OCH2CH2),
4.01 (t, 2H, J = 6.8 Hz, OCH2), 6.98 (d, 2H, J = 9.0 Hz, HPh), 7.50-7.47 (m, 4H, HPh), 7.81 (d, 2H, J =
13
9.0 Hz, HPh), 8.18 (s, 2H, HPh) C (DMSO-d6) : δ 14.1, 22.4, 25.8, 28.9, 29.0, 29.1, 29.2, 29.3, 31.6,

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371
67.9, 88.5, 90.7, 114.3, 115.2, 124.5, 130.4, 133.2, 134.6, 159.4 IR : 3400, 2920, 2850, 2216, 1600,
+
1404, 1380, 1340, 1286, 1450, 1019, 839, 827 cm-1 MS (IC+) m/z: 391 (M-CH4 ).
3-Chloro-6-dodecyloxypyridazine (26): To a solution of dodecan-1-ol (2.7 mL, 12.1 mmol) in 20 mL
of anhydrous THF under nitrogen at 0 °C was added n-BuLi (1.6 M in hexanes, 7.56 mL) dropwise. The
reaction mixture was stirred at rt for 30 min then a solution of 3,6-dichloropyridazine (1.5 g, 10.1 mmol)
in 10 mL of THF was added dropwise, the reaction mixture was heated to reflux with stirring overnight.
The reaction was quenched with a mixture of THF : HCl : EtOH (8:2:2) diluted with 20 mL of a mixture
of water and CH2Cl2 (1:1) and the organic layer separated. The aqueous layer was extracted with CH2Cl2
(2 x 20 mL). The combined organic extracts were dried over magnesium sulfate and evaporated. The
crude product was purified by column chromatography (silica gel, eluent petroleum ether : EtOAc (9:1))
to give 2.68 g (89 %) of 26 as a colorless solid. mp < 50 °C (lit.,19 mp 53-54 °C) 1H NMR (CDCl3) : δ 0.90
(t, J = 6.8 Hz, 3H, Me), 1.49-1.29 (m, 18H, 9 x CH2), 1.86-1.81 (m, 2H, CH2), 4.49 (t, J = 6.6 Hz, 4H, 2
x OCH2), 6.98 (d, J = 9.0 Hz, 1H, H5), 7.40 (d, J = 9.0 Hz, 1H, H4) 13C (CDCl3) : δ 14.5, 23.0, 26.3,
29.1, 29.7 (2C), 29.9 (3C), 30.0, 32.3, 63.3, 120.5, 131.0, 151.1, 164.8 IR : 2918, 2852, 1590, 1474,
1438, 1385, 1310, 994, 846, 704 cm-1 Anal. Calcd for C16H27ClN2O (298.18) : C, 64.30 H, 9.11 N, 9.37.
Found: C, 64.25 H, 9.11 N, 9.35.
3-[4-(4-Decyloxyphenylethynyl)phenyl]-6-dodecyloxypyridazine (27): Suzuki cross-coupling reaction
of 26 (359 mg, 1.20 mmol) with 25 (716 mg, 1.89 mmol) according to the general procedure A (t = 40
h) gave after purification by column chromatography (silica gel, eluent heptane : EtOAc (9:1)) 1.28 g
(73 %) of 27 as a yellow solid. mp 82 °C. 1H NMR (CDCl3) : δ 0.90 (t, 6H, J = 6.8 Hz, 2 x Me), 1.49-1.29
(m, 32H, 16 x CH2), 1.90-1.79 (m, 4H, 2 x OCH2CH2), 3.99 (t, J = 6.8 Hz, 2H, OCH2), 4.59 (t, J = 6.8 Hz,
2H, OCH2), 6.89 (d, 2H, J = 8.4 Hz, HPh), 7.04 (d, 1H, J = 9.2 Hz, HPh), 7.49 (d, 2H, J = 8.4 Hz, HPh),
7.65 (d, 2H, J = 8.4 Hz, HPh), 7.80 (d, 1H, J = 9.2 Hz, HPh), 8.04 (d, 2H, J = 8.4 Hz, HPh) 13C (CDCl3) : δ
14.5, 23.1, 26.4 (2C), 29.7, 29.8 (2C), 30.0 (2C), 30.1, 32.3, 68.2, 68.5, 88.1, 91.6, 115.0, 115.2, 118.2,
125.1, 126.6, 127.3, 132.3, 133.5, 135.9, 154.6, 159.8, 164.7 IR : 3071, 2918, 2850, 1599, 1447, 1433,
1310, 1286, 1251, 1021, 834 cm-1 Anal. Calcd for C40H56N2O2 (596.43): C, 80.49 H, 9.46 N, 4.69. Found:
C, 80.86 H, 9.57 N, 4.32.
3-Iodo-6-octyloxypyridazine (28): To a solution of octan-1-ol (0.71 mL, 4.50 mmol) in 20 mL of
anhydrous THF under nitrogen at 0 °C was added n-BuLi (2.5 M in hexanes, 1.80 mL) dropwise. The
reaction mixture was stirred at rt for 30 min then a solution of 3,6-diiodopyridazine (1.20 g, 3.62 mmol)

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in 10 mL of THF was added dropwise, the reaction mixture was heated to reflux with stirring overnight.
The reaction was quenched with a mixture of THF : HCl : EtOH (8:2:2) diluted with 20 mL of a mixture
of water and CH2Cl2 (1:1) and the organic layer separated. The aqueous layer was extracted with CH2Cl2
(2 x 20 mL). The combined organic extracts were dried over magnesium sulfate and evaporated. The
crude product was purified by column chromatography (silica gel, eluent petroleum ether: EtOAc (9:1))
1
to give 1.05 g (87 %) of 28 as a beige solid. mp <50 °C. H NMR (CDCl3) : δ 0.90 (t, J = 6.8 Hz, 3H,
Me), 1.48-1.30 (m, 10H, 5 x CH2), 1.88-1.80 (m, 2H, OCH2CH2), 4.42 (t, J = 6.8 Hz, 2H, OCH2), 6.66
(d, 1H, J = 9.2 Hz, H5), 7.62 (d, 1H, J = 9.2 Hz, H4) 13C (CDCl3) : δ 14.5, 23.0, 26.3, 29.0, 29.6, 29.7,
32.2, 68.3, 117.0, 119.6, 139.6, 165.2 IR : 3075, 2950, 2900, 1620, 1520, 1410, 1310, 1020 cm-1 Anal.
Calcd for C12H19IN2O (334.05): C, 43.13 H, 5.73 N, 8.38. Found: C, 43.05 H, 5.82 N, 8.34.
3-(4-Bromophenylethynyl)-6-octyloxypyridazine (29): Sonogashira cross-coupling reaction of 28
(303 mg, 0.91 mmol) with 1-bromo-4-ethynylbenzene (1.05 g, 5.83 mmol) according to the general
procedure B gave after purification by column chromatography (silica gel, eluent petroleum ether :
EtOAc (9:1)) 288 mg (82 %) of 29 as a brown solid. mp 114 °C. 1H NMR (CDCl3) : δ 0.90 (t, J = 6.8 Hz,
3H, Me), 1.48-1.30 (m, 10H, 5 x CH2), 1.88-1.80 (m, 2H, OCH2CH2), 4.54 (t, J = 6.8 Hz, 2H, OCH2),
13
6.92 (d, 1H, J = 9 Hz, HPh), 7.52-7.43 (m , 5H, HPh) C (CDCl3) : δ 14.5, 23.1, 26.3, 29.2, 29.6, 29.7,
32.2, 68.4, 87.2, 91.2, 117.1, 121.3, 124.0, 132.2, 132.7, 133.7, 143.5, 163.9 IR : 2954, 2920, 2852, 2223,
1488, 1428, 1288, 1006, 832 cm-1 Anal. Calcd for C20H23BrN2O (386.10): C, 62.02 H, 5.99 N, 7.23.
Found: C, 61.86 H, 6.24 N, 7.36.
3-(4'-Decyloxybiphenyl-4-ylethynyl)-6-octyloxypyridazine (30): Suzuki cross-coupling reaction of 29
(797 mg, 2.07 mmol) with decyloxyphenylboronic acid (972 mg, 3.50 mmol) according to the general
procedure C (t = 40 h) gave after purification by column chromatography (silica gel, eluent heptane :
EtOAc (7:3)) 817 mg (73 %) of 30 as a beige solid. mp 160 °C. 1H NMR (CDCl3) : δ 0.90 (t, J = 6.8 Hz,
6H, 2 x Me), 1.48-1.23 (m, 24H, 12 x CH2), 1.82-1.78 (m, 4H, 2 x OCH2CH2), 4.00 (t, J = 6.8 Hz, 2H,
OCH2), 4.55 (t, J = 6.8 Hz, 2H, OCH2), 6.92 (d, 1H, J = 9 Hz, HPh), 7.00-6.91 (m, 3H, HPh + H4), 7.63-7.50
(m, 7H, HPh + H5) 13C (CDCl3) : δ 14.5, 21.6, 24.9, 25.0 (2C), 27.8, 27.9, 28.2, 28.3, 28.4, 28.6, 28.7, 30.8,
30.9, 66.5, 66.9, 85.2, 91.1, 113.8, 115.6, 118.9, 125.5, 127.0, 131.2, 131.3, 131.4, 140.5, 142.4, 158.1,
162.4 IR : 2952, 2922, 2853, 2223, 1606, 1438, 1289, 1247, 822, 815 cm-1 Anal. Calcd for C36H48N2O2
(540.37): C, 79.96 H, 8.95 N, 5.18. Found: C, 80.26 H, 9.18 N, 4.99.

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