A facile route to Aryl-substituted 1,10-phenanthrolines by means of Suzuki coupling reactions between substituted areneboronic acids and halogeno-1,10-phenanthrolines

Article abstract of DOI:10.1002/1099-0690(200210)2002:19<3294::AID-EJOC3294>3.0.CO;2-Z

Twelve new mono- or diaryl-substituted 1,10-phenanthrolines (17 and 18) have been synthesized. The key step is a Suzuki coupling reaction between the substituted areneboronic acids 6, 11, and 15 and the mono- and dihalo-1,10-phenanthrolines 16. The syntheses of bis-ortho-substituted boronic acids 6, 11, and 15 from substituted arenes 5 or substituted bromoarenes 10 and 14 by lithiation and subsequent treatment with trimethyl borate is described. Not only 2,9-diiodo- (16c) but also 2,9-dichloro-1,10-phenanthroline (16b) can be used with good yields (65-92%) in the described Suzuki coupling. For the syntheses of unsymmetrically substituted 1,10-phenanthrolines 18b, 18i, and 18j, the use of 2- chloro-9-iodo-1,10-phenanthroline is not necessary; two different bis-ortho-substituted arene rings can be introduced stepwise in 46 to 64% total yield. ( Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002).

Full text of DOI:10.1002/1099-0690(200210)2002:19<3294::AID-EJOC3294>3.0.CO;2-Z

FULL PAPER
A Facile Route to Aryl-Substituted 1,10-Phenanthrolines by Means of Suzuki
Coupling Reactions between Substituted Areneboronic Acids and Halogeno-
1,10-phenanthrolines[‡]
Ulrich Lüning,*[a] Michael Abbass,[a] and Frank Fahrenkrug[a]
Keywords: Boronic acid / Catalysis / N ligands / Palladium / Suzuki coupling
Twelve new mono- or diaryl-substituted 1,10-phenanthrol-
can be used with good yields (65−92%) in the described Su-
ines (17 and 18) have been synthesized. The key step is a
zuki coupling. For the syntheses of unsymmetrically substi-
Suzuki coupling reaction between the substituted arene- tuted 1,10-phenanthrolines 18b, 18i, and 18j, the use of 2-
boronic acids 6, 11, and 15 and the mono- and dihalo-1,10-
phenanthrolines 16. The syntheses of bis-ortho-substituted
boronic acids 6, 11, and 15 from substituted arenes 5 or sub-
stituted bromoarenes 10 and 14 by lithiation and subsequent
treatment with trimethyl borate is described. Not only 2,9-
diiodo- (16c) but also 2,9-dichloro-1,10-phenanthroline (16b)
chloro-9-iodo-1,10-phenanthroline is not necessary; two dif-
ferent bis-ortho-substituted arene rings can be introduced
stepwise in 46 to 64% total yield.
( Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany,
2002)
Introduction
lysts in most of these cases are transition metal ion com-
plexes of these ligands, such as copper() complexes in the
The high selectivity of enzymes is largely caused by the stereoselective cyclopropanation of alkenes by diazoacet-
concave environment of the active site.[1] Geometrically re- ates.[7,10]
lated molecules such as macrocycles, clefts, or pincers have
therefore also found wide interest in supramolecular
chemistry.[2Ϫ5] Concave reagents have been developed to in-
crease the selectivity of reactions or catalyses by a corres-
ponding shielding of the reaction site. In particular, the con-
cave 1,10-phenanthrolines 1a have shown good selectivities
in a number of reactions.[6Ϫ10] The active and selective cata
Concave 1,10-phenanthrolines 1a have, since 1990, com-
monly been synthesized in a kinetically controlled double
macrocyclization[11] starting from a tetraphenol 2, which is
only
accessible
under
rather
extreme
reaction
conditions.[12Ϫ14] By separation of the macrocyclization
from the ether synthesis, followed by a ring-closing meta-
thesis and hydrogenolysis [see Scheme 1, PCy3 ϭ tris(cy-
clohexyl)phosphane], the yields have been improved consid-
erably (for instance, from 19 to 79%[14]).
For better manipulability of the selectivity of catalysis by
metal ion complexes of these concave ligands 1a, the intro-
duction of additional functional groups into the 1,10-phen-
anthroline ligands 1 would be desirable. These additional
functional groups can either be connected to the aryl
bridgeheads (as substituents R) or they can be part of the
bridges X. However, the harsh reaction conditions used
during the synthesis of the tetraphenol 2 (lithium powder,
MnO2, molten pyridinium chloride) are not compatible
with a broad variety of functional groups, and so another
method for the introduction of aryl rings into the 1,10-
phenanthroline system was necessary. Negishi and Suzuki
couplings[15Ϫ17] for the synthesis of diaryl-1,10-phenanthro-
lines have been described by Parker et al.[18] and Siegel et
al.[19,20]
[‡]
Concave Reagents, 37. Part 36: M. Gelbert, C. Körber,
O. Friedrich, F. Fahrenkrug, M. Keller, U. Lüning, Supramol.
Chem. 2002, 14, 199Ϫ210.
[a]
Institut für Organische Chemie, Universität Kiel,
This publication shows how the addition of aryllithium
compounds to 1,10-phenanthroline can be substituted by a
Suzuki coupling[18,21] between benzeneboronic acids 6, 11,
Olshausenstr. 40, 24098 Kiel, Germany
Fax: (internat.) ϩ49Ϫ(0)431/880-1558
E-mail: luening@oc.uni-kiel.de
3294
 WILEY-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002 1434Ϫ193X/02/1019Ϫ3294 $ 20.00ϩ.50/0 Eur. J. Org. Chem. 2002, 3294Ϫ3303

A Facile Route to Aryl-Substituted 1,10-Phenanthrolines
FULL PAPER
Scheme 3
Scheme 1
or 15 and the halogenated 1,10-phenanthrolines 16. We pre-
sent a number of new 2-aryl- and 2,9-diaryl-1,10-phen-
anthrolines 17 and 18 in which the aryl rings are always
doubly substituted in their ortho positions. In addition, the
resulting diaryl-1,10-phenanthrolines either carry func-
tional groups in the para position of a bridgehead or the
bridgeheads are alkylated with alkenyl groups at the four
oxygen atoms, ready for metathesis.[14]
Results
Scheme 4
Syntheses of Starting Materials
Schemes 2 to 4 summarize the syntheses of the ben-
zeneboronic acids 6, 11, and 15. All syntheses have in com-
While the synthesis of the boronic acid 6 was straightfor-
mon that a lithium aryl compound is treated with trimethyl ward,[22] the synthesis of the analogous, para-substituted
borate with subsequent hydrolysis. However, the lithium boronic acid 11 needed several steps, starting from the com-
aryl compound can either be obtained by lithiation of an mercially available carboxylic acid 7. From 7, the tetrahy-
unsubstituted position activated by neighboring oxygen dropyran-protected aryl bromide 10 was synthesized in 47%
atoms (Scheme 2), or it can be generated by bromine/li- total yield. From 10, the boronic acid was obtained by
thium exchange (Schemes 3 and 4). The boronic acids 6 and lithiation, treatment with trimethylborate, and subsequent
15 have been isolated and characterized. In the case of the hydrolysis, and was then used in the coupling reactions
boronic acid 11, crude 11 was used for the Suzuki coupling without isolation.
and gave excellent overall yields of 17b and 18b (91 and
88%, respectively).
The alkenyl-substituted boronic acids 15 were synthe-
sized from the corresponding bromides 14 in 83 to 86%
yield. While the alkenylation of the diphenol 13 with 1-
bromo-4-pentene or 1-bromo-5-hexene was possible in 93
and 87% yields, respectively, the synthesis of the homoal-
lylic bromo compound 14a could only be performed in 41%
yield, even when a large excess of the respective bromide
was used. Presumably, the small alkylation yield is caused
by competing HBr elimination from the homoallyl bromide.
Scheme 2
Eur. J. Org. Chem. 2002, 3294Ϫ3303
3295

U. Lüning, M. Abbass, F. Fahrenkrug
FULL PAPER
Table 1. Yields and reaction conditions for the coupling products 17 and 18 from Suzuki coupling between the boronic acids 6, 11, and
15 and the halogenated 1,10-phenanthrolines 16 and 17; the equivalents of catalyst were calculated from the amount of halo-1,10-
phenanthroline used, while the equivalents of base are relative to the amount of boronic acid
Product
Boronic
acid
Halogenated
1,10-phenanthroline
Reaction conditions[a]
Base
Yield
(%)
17a
17b
17f
17g
18a
18b
18f
18g
18g
18h
18h
18i
6
16a
16a
16b
16b
16b
17f
16b
16b
16c
16b
16c
17g
17g
5 mol %, DME, reflux 20 h
5 mol %, DME, reflux 20 h
5 mol %, DME, reflux 20 h
10 mol %, DME, reflux 16 h
10 mol %, DME, reflux 2 d
5 mol %, DME, reflux 2 d
10 mol %, DME, reflux 16 h
10 mol %, DME/H2O, reflux 16 h
10 mol %, DME, reflux 16 h
10 mol %, DME/H2O, reflux 16 h
10 mol %, DME, reflux 16 h
10 mol %, DME/H2O, reflux 16 h
10 mol %, DME/H2O, reflux 16 h
2  Na2CO3
2  Na2CO3
2  Na2CO3
2  Na2CO3
2  Na2CO3
2  Na2CO3
1.5 equiv. Ba(OH)2
1.5 equiv. Ba(OH)2
2 equiv. (nBu)4NF
1.5 equiv. Ba(OH)2
2 equiv. (nBu)4NF
1.5 equiv. Ba(OH)2
1.5 equiv. Ba(OH)2
73
91
73
71
83
88
78
92
88
73
88
65
88
11
6
15b
6
11
15a
15b
15b
15c
15c
15a
15c
18j
[a]
DME ϭ 1,2-dimethoxyethane, Pd(PPh3)4 was used as catalyst
When, however, the alkylation was carried out under Mitsu- to be substituted by iodide.[19] With the boronic acids 6 and
nobu conditions[23] with homoallylic alcohol, diethyl azod- 15b, however, 2,9-dichloro-1,10-phenanthroline (16b) could
icarboxylate (DEAD), and triphenylphosphane, bromo be selectively coupled with only one aryl unit to give 2-aryl-
compound 14a was obtained in 69% yield. All three brom- 9-chloro-1,10-phenanthrolines 17f and 17g in very good
ides 14 Ϫ even the homoallyl compound Ϫ gave the corres- yields (Scheme 5). Thus, there was no need to synthesize 2-
ponding boronic acids 15 in good yields (83 to 86%).
chloro-9-iodo-1,10-phenanthroline.[19]
Suzuki Couplings
As already described by Parker et al.[18] and Siegel et
al.,[19,20] halo-substituted 1,10-phenanthrolines can be
coupled with boronic acids under palladium catalysis con-
ditions.[24] Therefore, some boronic acids were first coupled
with 2,9-diiodo-1,10-phenanthroline (16c). When using the
alkene-substituted boronic acids 15 we feared that the Heck
reaction[15,25,26] might act as a competition reaction. We
therefore first checked Suzuki couplings in the absence of
strong bases. Fluoride ions[27] can also be used in Suzuki
reactions to activate the boronic acid, and good yields have
been found for fluoride-promoted Suzuki coupling when
aryl iodides have been used as reaction partners (Table 1,
compounds 18g and 18h).
With stronger bases, chloro-1,10-phenanthrolines[18] can
also be employed in Suzuki coupling, and Ϫ despite the
possibility of potentially competing Heck reactions Ϫ
identical or sometimes even better coupling yields were
achieved with the chloro-1,10-phenanthrolines 16a and 16b
in combination with sodium carbonate solution or barium
hydroxide[24,28] (Table 1, compounds 18g and 18h). This
method has the advantage that it avoids the reaction step
from the dichloro-1,10-phenanthroline 16a to the diiodo
analogue 16c.
Unsymmetrically substituted 2,9-diaryl-1,10-phenanthro-
lines have previously been synthesized by traditional Sauv-
age chemistry;[29] unsymmetrical Suzuki coupling products
have also been obtained but only when starting from 2-
chloro-9-iodo-1,10-phenanthroline.[30] In those cases, prior
to a second coupling, the remaining chlorine atom first had Scheme 5
3296
Eur. J. Org. Chem. 2002, 3294Ϫ3303

A Facile Route to Aryl-Substituted 1,10-Phenanthrolines
FULL PAPER
The yields and reaction conditions for all the Suzuki
couplings carried out in this work are summarized in
Table 1. The monoaryl coupling products 17 were obtained
in 71 to 91% yields. In the case of the diaryl-1,10-phen-
anthrolines 18, simultaneous coupling in the 2- and 9-posi-
tions yielded the symmetrical compounds 18a and 18f؊h in
73 to 92% yields. The unsymmetrically substituted diaryl-
1,10-phenanthrolines 18b, 18i, and 18j were obtained in
overall yields of 64, 46, and 63%, respectively.
The resulting 2-aryl and 2,9-diaryl-substituted 1,10-phen-
anthrolines 17 and 18 are new, interesting intermediates for
the synthesis of concave 1,10-phenanthrolines 1. However,
these nonmacrocyclic precursors are also often already suf-
ficiently shielded to allow remarkable increases in selectiv-
ity.[9]
Experimental Section
General Remarks: The following chemicals were obtained commer-
cially and were used without further purification: 3,4-dihydro-2H-
pyran (Fluka), diisopropylaluminium hydride (1.0  in hexanes,
Aldrich), 4-bromo-3,5-dihydroxybenzoic acid (Aldrich, Lancaster),
diethyl malonate (Janssen), N,N-dimethylformamide (Fluka,
Ն99.8%), dimethyl sulfate (Merck), resorcinol (Riedel de Hae¨n),
tetrakis(triphenylphospane)palladium(0) (Aldrich), dimethoxye-
thane (Aldrich), 3-buten-1-ol (Fluka), 5-bromo-1-pentene (Fluka),
6-bromo-1-hexene (Fluka), diethyl azodicarboxylate (Fluka), tri-
phenylphosphane (Aldrich), trimethyl borate (Fluka), n-butylli-
thium (2.5  in hexanes, Aldrich).
2-Chloro-1,10-phenanthroline (16a), 2,9-dichloro-1,10-phenanthro-
line (16b), and 2,9-diiodo-1,10-phenanthroline (16c) were prepared
according to literature procedures.[19,32]
The synthesis of bimacrocycles 1 from the symmetrically
alkenylated intermediates 18g and 18h (although obtained
by a different route) by ring-closing metathesis has already
been described.[14]
Dry solvents were obtained with suitable desiccants: ethanol was
distilled from sodium, tetrahydrofuran from lithium aluminium hy-
dride, and ethyl acetate and acetone were distilled from calcium
chloride. Column chromatography was carried out on basic alu-
mina (Fluka, activity I) or silica gel (MachereyϪNagel, activity 1).
The 1H NMR and 13C NMR spectra were recorded on Bruker
AC 200 (200 MHz), AM 300 (300 MHz or 75 MHz) or DRX 500
(500 MHz or 125 MHz) instruments, with tetramethylsilane as in-
ternal standard. IR spectra were measured on a PerkinϪElmer
1600 Series machine, MS spectra were recorded on a Finnigan
MAT 8230, and elemental analyses were carried out on a VarioEl
(Elementaranalysensysteme GmbH) instrument. Gas chromato-
graphy was performed with a Varian 3400 gas chromatograph
equipped with a MachereyϪNagel SE30/25 m column.
The conversion of the group R1 at the bridgehead and
an illustrative connection with a carbon nucleophile (here
malonate) is shown in Figure 1.
2,6-Dimethoxybenzeneboronic Acid (6): The synthesis was carried
in analogy to the procedure of Kuivila and Nahabedian,[22] starting
from 80 mmol and giving 2.6 g of 6 (18%). M.p. 105Ϫ113 °C. IR
(KBr): ν˜ ϭ 3332 (OϪH), 2993, 2926, 2832 (aliph. CϪH), 1598,
1466 (arom.) cmϪ1. 1H NMR (300 MHz, CDCl3): δ ϭ 3.92 (s, 6 H,
ArOCH3), 6.64 (d, J ϭ 8.4 Hz, 2 H, 3,5-H), 7.24 (s, 2 H, OH), 7.40
(t, J ϭ 8.4 Hz, 1 H, 4-H) ppm. MS (EI, 70 eV): m/z (%) ϭ 182,
181 (100, 28) [Mϩ]; 164, 163 (34, 10) [Mϩ Ϫ H2O]; 137 (14) [Mϩ
Ϫ B(OH)2].
Figure 1. a) pTsOH, EtOH; b) conc. HCl; c) conc. HCl;
d) CH2(COOEt)2, NaH, DMF; THP ϭ tetrahydropyran-2-yl
Methyl 4-Bromo-3,5-dimethoxybenzoate (8): 4-Bromo-3,5-dihy-
droxybenzoic acid (7, 4.74 g, 20.3 mmol) was dissolved in acetone
(100 mL). After addition of potassium carbonate (8.71 g,
63.0 mmol) and dimethyl sulfate (6.0 mL, 63 mmol), the mixture
was heated under reflux for 4 h. The solvent was removed in vacuo
and the residue was dissolved in water and diethyl ether (100 mL
each). The water layer was extracted with diethyl ether (3 times, 50
mL each) and the combined organic layer was dried with magnes-
ium sulfate. The solvent was evaporated in vacuo and the residue
was purified by recrystallization from methanol, yielding 4.23 g
(76%) of 8. M.p. 114Ϫ116 °C. IR[33] (KBr): ν˜ ϭ 3001 (arom. CϪH),
In the para-substituted mono- or diaryl-1,10-phenanthro-
lines 17b and 18b, one aryl ring possesses an additional
functional group R1 in the para position. The benzylic alco-
hol 17c can be liberated from the tetrahydropyranyl ether
17b by acidic hydrolysis in 73% yield. Subsequent treatment
of 17c with concentrated hydrochloric acid yields the benzyl
chloride 17d in 83% yield. However, 17d could also be gen-
erated in one step from the THP ether 17b in 64% yield
when concentrated hydrochloric acid was used for the cleav-
age. Analogously the chloride 18d could be obtained in one
step from 18b in 82% yield. As a first example of further
functionalization, both chlorides 17d and 18d were substi-
tuted with diethyl malonate nucleophile to give the diesters
17e and 18e in 52 and 48% yields, respectively. One poten-
tial application of such a ‘‘malonated’’ ligand 17e or 18e is
the amidation of the ester groups with oligopeptides, which
would allow the production of ‘‘libraries"[31] of substituted
diaryl 1,10-phenanthrolines.
2955 (aliph. CϪH), 1717 (CϭO), 1587, 1458 (arom.) cmϪ1 1H
.
NMR[33] (300 MHz, CDCl3): δ ϭ 3.90 (s, 3 H, ArCOOCH3), 3.93
(s, 6 H, ArOCH3), 7.25 (s, 2 H, ArH) ppm. MS (EI, 70 eV): m/z
(%) ϭ 276, 274 (98, 100) [Mϩ]; 245, 243 (54, 56) [Mϩ Ϫ CH3O].
4-Bromo-3,5-dimethoxyphenylmethanol (9):[33] Methyl 4-bromo-3,5-
dimethoxybenzoate (8, 11 g, 40 mmol) was dissolved in tetrahy-
drofuran (50 mL). After the addition of a solution of diisopropylal-
uminium hydride (1.0  in hexanes, 100 mL, 100 mmol), the reac-
tion mixture was stirred for 2 h at room temperature. Water (15
mL) was added. The precipitated solid was filtered off and washed
Eur. J. Org. Chem. 2002, 3294Ϫ3303
3297

U. Lüning, M. Abbass, F. Fahrenkrug
FULL PAPER
several times with ethyl acetate. The filtrate was evaporated, and
8.1 g (33 mmol, 81%) of 9 precipitated, m.p. 119Ϫ121 °C. IR
OCH2CH2), 4.07 (t, J ϭ 6.8 Hz, 4 H, OCH2), 5.12, 5.19 (tdd, Jt ഠ
1.1 Hz, Jd ϭ 1.9 Hz, Jd ϭ 10.2 Hz, ϭCHHcis; tdd, Jt ഠ 1.8 Hz,
(KBr): ν˜ ϭ 3247 (OϪH), 2955 (aliph. CϪH), 1591, 1454 (arom.), Jd ഠ 1.9 Hz, Jd ϭ 17.2 Hz, ϭCHHtrans, 4 H), 5.96 (tdd, Jt ϭ
1245, 1127 (CϪOϪC) cmϪ1 1H NMR (300 MHz, CDCl3): δ ϭ 6.8 Hz, Jd ϭ 10.2 Hz, Jd ϭ 17.2 Hz, 2 H, CHϭ), 6.54 (d, J ϭ
1.88 (s, 1 H, OH), 3.90 (s, 6 H, ArOCH3), 4.67 (s, 2 H, ArCH2OH), 8.3 Hz, 2 H, 4,6-H), 7.17 (t, J ϭ 8.3 Hz, 1 H, 5-H) ppm. 13C NMR
6.59 (s, 2 H, ArH) ppm. MS: (EI, 70 eV): m/z (%) ϭ 248, 246 (96, (75 MHz, CDCl3): δ ϭ 33.6 (t, OCH2CH2), 68.6 (t, OCH2), 102.3
100) [Mϩ]; 233, 231 (7, 11) [Mϩ Ϫ CH3]; 217, 215 (7, 11) [Mϩ (s, 2-C), 106.0 (d, 4,6-C), 117.3 (t, ϭCH2), 128.0 (d, 5-C), 134.2 (d,
.
Ϫ CH3O].
CHϭ), 156.6 (s, 1,3-C) ppm. MS: (EI, 70 eV): m/z (%) ϭ 298, 296
(32, 31) [Mϩ]; 217 (99) [Mϩ Ϫ Br]; 190, 188 (78, 89) [Mϩ Ϫ C8H12].
C14H17BrO2 (297.19), calcd. C 56.58, H 5.77; found C 56.57,
H 5.60.
2-[(4-Bromo-3,5-dimethoxybenzyl)oxy]tetrahydro-2H-pyran (10): 4-
Bromo-3,5-dimethoxyphenylmethanol (9, 8.03 g, 32.5 mmol) was
dissolved in dry dichloromethane (200 mL). After the addition of
3,4-dihydro-2H-pyran (7.4 mL, 81 mmol) and p-toluenesulfonic 2-Bromo-1,3-bis(pent-4-enoxy)benzene (14b): 2-Bromo-1,3-dihy-
acid (108 mg, 568 µmol), the reaction mixture was stirred for 16 h
at room temperature. The solvent was removed and the residue was
purified by chromatography (silica gel, dichloromethane), yielding
droxybenzene (13, 1.60 g, 8.47 mmol) was dissolved in dry N,N-
dimethylformamide. After the addition of potassium carbonate
(7.00 g, 50.6 mmol), potassium iodide (500 mg, 3.01 mmol), and 5-
8.30 g (77%) of 10 as a colorless solid. IR (KBr): ν˜ ϭ 2971, 2835 bromo-1-pentene (2.50 mL, 21.1 mmol), the reaction mixture was
(aliph. CϪH), 1588, 1464 (arom.), 1234, 1123 (CϪOϪC) cmϪ1. 1H stirred for 16 h at 60 °C. The solvent was removed in vacuo and
NMR (300 MHz, CDCl3): δ ϭ 1.4Ϫ1.9 (m, 6 H, CH2), 3.5Ϫ3.6
the residue was dissolved in water and diethyl ether (20 mL each).
(m, 1 H, CH2O), 3.9Ϫ4.0, 3.91 (m, CH2O, s, ArOCH3; 7 H), 4.49 The water layer was extracted with diethyl ether (3 times, 20 mL
(d, J ϭ 12.3 Hz, 1 H, ArCH2O), 4.7 (m, 1 H, OCHO), 4.75 (d, J ϭ each), and the combined organic layer was washed with sodium
12.3 Hz, 1 H, ArCH2O), 6.60 (s, 1 H, ArH) ppm. 13C NMR
hydroxide (2 , 3 times, 20 mL each) and saturated aqueous sodium
(75 MHz, CDCl3): δ ϭ 19.5 (t, CH2), 25.4 (t, CH2), 30.6 (t, CH2), chloride and dried with magnesium sulfate. The solvent was evap-
56.4 (q, ArOCH3), 62.4 (t, ArCH2O), 68.6 (t, CH2O), 97.8 (d, orated in vacuo and the residue was purified by column chromato-
OCHO), 99.6 (s, 4-C), 104.0 (d, 2,6-C), 139.1 (s, 1-C), 157.0 (s, 3,5-
C) ppm. MS (EI, 70 eV): m/z (%) ϭ 332, 330 (3, 4) [Mϩ]; 232, (93%) of 14b as a colorless oil. GC (SE30/25 m, temp. program[35]):
230 (62, 60) [Mϩ Ϫ C5H8O2]; 231, 229 (62, 60) [Mϩ Ϫ C5H9O2].
Ret ϭ 18.32 min, purity: 99%. IR (film): ν˜ ϭ 3076 (arom. CϪH),
C14H19BrO4 (331.21), calcd. C 50.77, H 5.78; found C 50.44, 2940, 2876 (aliph. CϪH), 1640 (aliph. CϭC), 1591, 1459 (arom.),
graphy (silica gel, cyclohexane/ethyl acetate, 90:10), yielding 2.56 g
t
H 5.56.
1097 (CϪOϪC), 1036 (arom. C-Br) cmϪ1 1H NMR (300 MHz,
.
CDCl3): δ ϭ 1.93 (mc, 4 H, OCH2CH2), 2.30 (mc, 4 H, CH2CHϭ),
4.03 (t, J ϭ 6.3 Hz, 4 H, OCH2), 5.00, 5.07 (tdd, Jt ϭ 1.2 Hz, Jd ϭ
2.0 Hz, Jd ϭ 10.2 Hz, ϭCHHcis; tdd, Jt ϭ 1.5 Hz, Jd ϭ 2.0 Hz,
2-Bromo-1,3-dihydroxybenzene (13):[34] Sodium hydroxide (20.0 g,
500 mmol) and sodium sulfite (63.0 g, 500 mmol) were dissolved in
water (625 mL) and methanol (125 mL). After addition of 2,4,6-
tribromoresorcinol (86.7 g, 250 mmol), the reaction mixture was
stirred for 15 min at room temperature. The mixture was then acidi-
fied with 2  hydrochloric acid, and most of the methanol was
removed in vacuo. After extraction with diethyl ether (6 times, 100
mL each), the solvent was removed in vacuo and the residue was
recrystallized from chloroform, yielding 30.7 g (65%) of 13. M.p.
101Ϫ102 °C. GC (SE30/25 m, temp. program[35]): tRet ϭ 6.44 min,
purity: 99%. IR (KBr): ν˜ ϭ 3330 (OϪH), 1600, 1585, 1467 (arom.),
Jd ϭ 17.1 Hz, ϭCHHtrans; 4 H), 5.86 (tdd, Jt ϭ 6.7 Hz, Jd ϭ
10.2 Hz, Jd ϭ 17.1 Hz, 2 H, CHϭ), 6.53 (d, J ϭ 8.3 Hz, 2 H, 4,6-
H), 7.16 (t, J ϭ 8.3 Hz, 1 H, 5-H) ppm. 13C NMR (75 MHz,
CDCl3): δ ϭ 28.3 (t, CH2CHϭ), 30.1 (t, OCH2CH2), 68.4 (t,
OCH2), 102.1 (s, 2-C), 105.7 (d, 4,6-C), 115.3 (t, ϭCH2), 128.0 (d,
5-C), 137.8 (d, CHϭ), 156.7 (s, 1,3-C) ppm. MS (CI, 70 eV): m/z
(%) ϭ 327, 325 (26, 25) [Mϩ ϩ H]. MS (EI, 70 eV): m/z (%) ϭ 245
(100) [Mϩ Ϫ Br]; 190, 188 (84, 88) [Mϩ Ϫ C10H16]. C16H21BrO2
(325.24), calcd. C 59.09, H 6.51; found C 58.97, H 6.37.
1
1296 (OϪH), 1234, 1188 (CϪOH), 1035 (arom. CϪBr) cmϪ1. H
NMR (200 MHz, CDCl3): δ ϭ 5.42 (s, 2 H, OH), 6.60 (d (AB2), 2-Bromo-1,3-bis(hex-5-enoxy)benzene (14c): As described for 14b,
J ഠ 8.2 Hz, 2 H, 4,6-H), 7.11 (dd (AB2), J ഠ 7.8 Hz, J ഠ 8.5 Hz, 13 (7.46 mmol) was treated with excess 6-bromo-1-hexene, giving
1 H, 5-H) ppm. MS (EI, 70 eV): m/z (%) ϭ 190, 188 (98, 100) [Mϩ]; 2.30 g (87%) of 14c as a colorless oil. GC (SE30/25 m, temp. pro-
172, 170 (37, 38) [Mϩ Ϫ H2O].
gram[35]): tRet ϭ 20.51 min, purity: 93%. IR (film): ν˜ ϭ 2935 (aliph.
CϪH), 1592, 1460 (arom.), 1097 (CϪOϪC) cmϪ1 1H NMR
.
2-Bromo-1,3-bis(but-3-enoxy)benzene (14a): A solution of diethyl
azodicarboxylate (4.86 mL, 24.9 mmol) in tetrahydrofuran (6 mL)
was added at 0 °C to a solution of 2-bromo-1,3-dihydroxybenzene
(13, 1.47 g, 7.78 mmol), triphenylphosphane (4.91 g, 18.7 mmol),
and 3-butene-1-ol (2.00 mL, 24.9 mmol) in tetrahydrofuran (20
mL). After the mixture had been stirred for 2 h at room temper-
ature, water (20 mL) was added. The water layer was extracted with
diethyl ether (3 times, 20 mL each), and the combined organic layer
was washed with aqueous sodium hydroxide (2 , 3 times, 20 mL
each) and with saturated sodium chloride solution and was then
dried with magnesium sulfate. The solvent was evaporated and the
residue was filtered through silica gel (cyclohexane/ethyl acetate,
95:5) and purified by column chromatography (silica gel, cyclohex-
ane/ethyl acetate, 90:10), yielding 1.57 g (69%) of 14a. M.p. 31 °C.
GC (SE30/25 m, temp. program[35]): tRet ϭ 16.32 min, purity: 97%.
(300 MHz, CDCl3): δ ϭ 1.62 (mc, 4 H, OCH2CH2CH2), 1.85 (mc,
4 H, OCH2CH2), 2.14 (mc, 4 H, CH2CHϭ), 4.03 (t, J ϭ 6.4 Hz,
4 H, OCH2), 4.97, 5.04 (tdd, Jt ϭ 1.2 Hz, Jd ϭ 2.1 Hz, Jd ϭ
10.2 Hz, ϭCHHcis; tdd, Jt ϭ 1.5 Hz, Jd ϭ 2.1 Hz, Jd ϭ 17.1 Hz,
ϭCHHtrans; 4 H), 5.84 (tdd, Jt ϭ 6.7 Hz, Jd ϭ 10.2 Hz, Jd ϭ
17.1 Hz, 2 H, CHϭ), 6.53 (d, J ϭ 8.3 Hz, 2 H, 4,6-H), 7.16 (t, J ϭ
8.3 Hz, 1 H, 5-H) ppm. 13C NMR (75 MHz, CDCl3): δ ϭ 25.3 (t,
OCH2CH2CH2), 28.6 (t, OCH2CH2), 33.4 (t, CH2CHϭ), 69.1 (t,
OCH2), 102.1 (s, 2-C), 105.7 (d, 4,6-C), 114.7 (t, ϭCH2), 128.0 (d,
5-C), 138.6 (d, CHϭ), 156.7 (s, 1,3-C) ppm. MS (CI, 70 eV): m/z
(%) ϭ 355, 353 (100, 98) [Mϩ ϩ H]. MS (EI, 70 eV): m/z (%) ϭ
273 (90) [Mϩ Ϫ Br]; 190, 188 (100, 99) [Mϩ Ϫ C12H20]. C18H25BrO2
(353.30), calcd. C 61.19, H 7.13; found C 61.03, H 7.39.
2,6-Bis(but-3-enoxy)benzeneboronic Acid (15a): 2-Bromo-1,3-
IR (KBr): ν˜ ϭ 2926 (aliph. CϪH), 1643 (aliph. CϭC), 1593 bis(but-3-enoxy)benzene (14a, 1.30 g, 4.42 mmol) was dissolved in
(arom.), 1095 (CϪOϪC), 1034 (arom. C-Br) cmϪ1 1H NMR tetrahydrofuran (20 mL). At -78 °C, n-butyllithium (2.5  in hex-
.
(300 MHz, CDCl3): δ ϭ 2.60 (qt, Jq ϭ 6.8 Hz, Jt ϭ 1.4 Hz, 4 H,
anes, 1.90 mL, 4.80 mmol) was added and the reaction mixture was
3298
Eur. J. Org. Chem. 2002, 3294Ϫ3303

A Facile Route to Aryl-Substituted 1,10-Phenanthrolines
FULL PAPER
stirred at Ϫ78 °C for 1 h. After the addition of trimethyl borate
(1.60 mL, 14.4 mmol), stirring was continued for 2 h while the reac-
tion mixture was allowed to warm up to room temperature. Water
(20 mL) was added, the water layer was extracted with diethyl ether
(3 times, 20 mL each), and the combined organic layer was washed
with saturated aqueous sodium chloride and dried with magnesium
sulfate. After evaporation of the solvent in vacuo, the residue was
purified by column chromatography (silica gel, cyclohexane/ethyl
acetate, 85:15, until all starting material was collected, then 50:50),
yielding 956 mg (83%) of 15a. M.p. 78Ϫ79 °C. IR (KBr): ν˜ ϭ 3489
(OϪH), 2947, 2878 (aliph. CϪH), 1645 (aliph. CϭC), 1598, 1574
154 (16) [Mϩ Ϫ C12H20]. C18H27BO4 (318.22), calcd. C 67.94,
H 8.55; found C 68.11, H 8.74.
2-(2,6-Dimethoxyphenyl)-1,10-phenanthroline (17a): 2-Chloro-1,10-
phenanthroline (16a, 373 mg, 1.74 mmol), 2,6-dimethoxybenzene-
boronic acid (3, 317 mg, 1.74 mmol), and tetrakis(triphenylphos-
phane)palladium(0) (100 mg, 87.0 µmol) were dissolved in dime-
thoxyethane (10 mL). After addition of aqueous sodium carbonate
(2 , 1.8 mL), the reaction mixture was heated under reflux for
20 h. Water and dichloromethane (10 mL each) were added, the
water layer was extracted with dichloromethane (3 times, 15 mL
each), and the combined organic layer was washed with saturated
aqueous sodium chloride and dried with magnesium sulfate. The
solvent was evaporated in vacuo and the residue was purified by
recrystallization from chloroform/methanol, yielding 398 mg (72%)
of 17a. The spectroscopic data were in accordance with the literat-
ure.[11]
1
(arom.), 1101 (CϪOϪC) cmϪ1. H NMR (300 MHz, CDCl3): δ ϭ
2.61 (qt, Jq ഠ 6.4 Hz, Jt ഠ 1.4 Hz, 4 H, OCH2CH2), 4.12 (t, J ϭ
6.3 Hz, 4 H, OCH2) 5.19, 5.24 (tdd, Jt ഠ 1.5 Hz, Jd ഠ 1.6 Hz, Jd ϭ
10.2 Hz, ϭCHHcis; tdd, Jd ഠ 1.5 Hz, Jd ഠ 1.6 Hz, Jd ϭ 17.1 Hz,
ϭCHHtrans
; 4 H), 5.86 (tdd, Jt ϭ 6.8 Hz, Jd ϭ 10.2 Hz, Jd ϭ
17.1 Hz, 2 H, CHϭ), 6.60 (d, J ϭ 8.4 Hz, 2 H, 3,5-H), 7.21 (s, 2 H,
OH), 7.35 (t, J ϭ 8.4 Hz, 1 H, 4-H) ppm. 13C NMR (75 MHz,
CDCl3): δ ϭ 33.6 (t, OCH2CH2), 67.7 (t, OCH2), 105.0 (d, 3,5-C),
118.3 (t, ϭCH2), 132.8 (d, 4-C), 133.6 (d, CHϭ), 164.7 (s, 2,6-C).
Because of relaxation effects with 11B-isotopes the signal for 1-C is
not detectable. MS (EI, 70 eV): m/z (%) ϭ 262 (52) [Mϩ]; 208 (32)
[Mϩ Ϫ C4H6]; 154 (83) [Mϩ Ϫ C8H12]. C14H19BO4 (262.11) calcd.
C 64.15, H 7.31; found C 63.88, H 7.15.
2-{2,6-Dimethoxy-4-[(2-tetrahydropyranyloxy)methyl]phenyl}-
1,10-phenanthroline (17b): 2-Bromo-1,3-dimethoxy-5-[(2-tetrahy-
dropyranyloxy)methyl]benzene (10, 2.000 g, 6.039 mmol) was dis-
solved in tetrahydrofuran (40 mL). At Ϫ70 °C, n-butyllithium (2.5
 in hexanes, 2.70 mL, 6.75 mmol) was added and the reaction
mixture was stirred for 30 min at Ϫ70 °C. After the addition of
trimethyl borate (2.1 mL, 19 mmol), stirring was continued for 1 h,
during which the reaction mixture was allowed to warm up to room
temperature. Water (40 mL) was added, the water layer was ex-
tracted with diethyl ether (3 times, 40 mL each), and the combined
organic layer was washed with saturated aqueous sodium chloride
and was dried with magnesium sulfate. After evaporation of the
solvent in vacuo, the residue, 2-chloro-1,10-phenanthroline (16a,
1.166 g, 5.435 mmol), and tetrakis(triphenylphosphane)pallad-
ium(0) (360 mg, 313 µmol) were dissolved in dimethoxyethane (60
mL). After the addition of aqueous sodium carbonate (2 , 6 mL),
the reaction mixture was heated under reflux for 20 h. Water and
dichloromethane (60 mL each) were added, the water layer was
extracted with dichloromethane (3 times, 60 mL each), and the
combined organic layer was washed with saturated aqueous sodium
chloride and dried with magnesium sulfate. The solvent was evap-
orated in vacuo and the residue was purified by recrystallization
from chloroform/n-pentane, yielding 2.14 g (91%) of 17b. M.p. 155
°C. IR (KBr): ν˜ ϭ 2932, 2864 (aliph. CϪH), 1582, 1455 (arom.),
2,6-Bis(pent-4-enoxy)benzeneboronic Acid (15b): The synthesis was
carried out analogously to that of 15a, on a 5Ϫ10 mmol scale. Col-
umn chromatography was performed on silica gel (cyclohexane/
ethyl acetate, 85:15). A 7.46 mmol batch gave 1.91 g (86%) of 15b.
M.p. 37Ϫ37.5 °C. IR (KBr): ν˜ ϭ 3510 (OϪH), 3080 (arom. CϪH),
2945 (aliph. CϪH), 1644 (aliph. CϭC), 1595, 1573 (arom.), 1099
(CϪOϪC) cmϪ1. 1H NMR (300 MHz, CDCl3): δ ϭ 1.96 (mc, 4 H,
OCH2CH2), 2.25 (mc, 4 H, CH2CHϭ), 4.09 (t, J ϭ 6.5 Hz, 4 H,
OCH2), 5.03, 5.08 (tdd, Jt ഠ 1.5 Hz, Jd ഠ 1.9 Hz, Jd ϭ 10.2 Hz,
ϭCHHcis; tdd, Jt ഠ 1.5 Hz, Jd ഠ 1.9 Hz, Jd ϭ 17.2 Hz, ϭCHHtrans
;
4 H), 5.82 (tdd, Jt ϭ 6.7 Hz, Jd ϭ 10.2 Hz, Jd ϭ 17.2 Hz, 2 H,
CHϭ), 6.60 (d, J ϭ 8.4 Hz, 2 H, 3,5-H), 7.35 (t, J ϭ 8.4 Hz, 1 H,
4-H), 7.35 (s, 2 H, OH) ppm. 13C NMR (75 MHz, CDCl3): δ ϭ
28.3 (t, CH2CHϭ), 30.0 (t, OCH2CH2), 68.3 (t, OCH2), 105.2 (d,
3,5-C), 106.4 (s, 1-C)*, 115.2 (t, ϭCH2), 132.9 (d, 4-C), 137.0 (d,
CHϭ), 164.7 (s, 2,6-C). * Intensity of the signal is very low (see
above). MS (EI, 70 eV): m/z (%) ϭ 290 (28) [Mϩ]; 154 (73) [Mϩ
Ϫ
1228, 1127 (CϪOϪC) cmϪ1 1H NMR (500 MHz, CDCl3): δ ϭ
.
C10H16]. C16H23BO4 (290.17), calcd. C 66.23, H 7.99; found
C 66.37, H 7.78.
1.7Ϫ1.9 (m, 6 H, CH2), 2.28 (H2O, ca. 0.5 H), 3.5Ϫ3.6 (m, 1 H,
CH2O), 3.70 (s, 6 H, ArOCH3), 3.9Ϫ4.0 (m, 1 H, CH2O), 4.60 (d,
J ϭ 12.3 Hz, 1 H, ArCH2O), 4.74 (dd, J ϭ 2.9 Hz, J ϭ 4.5 Hz, 1
H, OCHO), 4.82 (d, J ϭ 12.3 Hz, 1 H, ArCH2O), 6.68 (s, 2 H,
ArH), 7.26 (s, 1 H, CHCl3), 7.56 (dd, J ϭ 4.3 Hz, J ϭ 8.0, 1 H, 8-
H), 7.61 (d, J ϭ 8.1 Hz, 1 H, 3-H), 7.77 (mc, 2 H, 5,6-H), 8.20 (dd,
J ϭ 1.8 Hz, J ϭ 8.1 Hz, 1 H, 7-H), 8.23 (d, J ϭ 8.2 Hz, 1 H,
4-H), 9.18 (dd, J ϭ 1.8 Hz, J ϭ 4.3 Hz, 1 H, 9-H) ppm. 13C NMR
(125 MHz, CDCl3): δ ϭ 19.6, 25.5, 30.7 (3 t, CH2), 56.0 (q,
ArOCH3), 62.5 (t, ArCH2O), 68.9 (t, CH2O), 97.4 (d, OCHO),
103.9 (d, 3Ј,5Ј-C), 119.4 (s, 1Ј-C), 122.6 (d, 8-C), 126.1, 126.1, 126.6
(3 d, 3,5,6-C), 127.4, 128.7 (2 s, 4a,6a-C), 135.5, 135.8 (2 d, 4,7-C),
140.2 (s, 4Ј-C), 146.3, 146.6 (2 s, 10a,10b-C), 150.2 (d, 9-C), 155.7
(s, 2-C), 158.5 (s, 2Ј,6Ј-C) ppm. MS: (EI, 70 eV): m/z (%) ϭ 430
(87) [Mϩ]; 429 (100) [Mϩ Ϫ H]; 412 (25) [Mϩ Ϫ H2O]; 345 (10)
2,6-Bis(hex-5-enoxy)benzeneboronic acid (15c): The synthesis was
carried out analogously to that of 15a, on a 5Ϫ10 mmol scale. Col-
umn chromatography was performed on silica gel (cyclohexane/
ethyl acetate, 85:15). A 5.66 mmol batch gave 1.54 g (86%) of 15c.
M.p: 58Ϫ59 °C. IR (KBr): ν˜ ϭ 3504 (OϪH), 3072 (arom. CϪH),
2944 (aliph. CϪH), 1640 (aliph. CϭC), 1595 (arom.), 1103
(CϪOϪC) cmϪ1. 1H NMR (300 MHz, CDCl3): δ ϭ 1.60 (mc, 4 H,
OCH2CH2CH2), 1.88 (mc, 4 H, OCH2CH2), 2.13 (mc, 4 H,
CH2CH2ϭ), 4.08 (t, J ϭ 6.5 Hz, 4 H, OCH2), 4.99, 5.03 (tdd, Jt ഠ
1.5 Hz, Jd ϭ 2.0 Hz, Jd ϭ 10.2 Hz, ϭCHHcis; tdd, Jt ഠ 1.5 Hz,
Jd ϭ 2.0 Hz, Jd ϭ 17.1 Hz, ϭCHHtrans
; 4 H), 5.81 (tdd, Jt ϭ
6.7 Hz, Jd ϭ 10.2 Hz, Jd ϭ 17.1 Hz, 2 H, CHϭ), 6.60 (d, J ϭ
8.4 Hz, 2 H, 3,5-H), 7.34 (t, J ϭ 8.4 Hz, 1 H, 4-H), 7.36 (s, 2 H,
OH) ppm. 13C NMR (75 MHz, CDCl3): δ ϭ 25.1 (t,
OCH2CH2CH2), 28.5 (t, OCH2CH2), 33.2 (t, CH2CHϭ), 68.8 (t,
OCH2), 105.0 (d, 3,5-C), 105.0 (s, 1-C)*, 115.1 (t, ϭCH2), 132.8 (d,
4-C), 137.5 (d, CHϭ), 164.9 (s, 2,6-C). * Intensity of the signal is
[Mϩ Ϫ C5H9O]; 330 (10) [Mϩ Ϫ C6H12O]; 329 (16) [Mϩ
Ϫ
C6H13O]; 312 [Mϩ Ϫ C6H14O2]. C26H26N2O4 (430.50): calcd.
C 72.54, H 6.09, N 6.51, C48H56N2O4·0.9CHCl3·0.1H2O, calcd.
C 59.86, H 5.06, N 5.19, found C 59.60, H 4.69, N 5.03.
very low (see above). MS (CI, 70 eV): m/z (%) ϭ 319 (100) [Mϩ
ϩ
2-[2,6-Dimethoxy-4-(hydroxymethyl)phenyl]-1,10-phenanthroline
(17c): A solution of p-toluenesulfonic acid (133 mg, 699 µmol) in
H]. MS (EI, 70 eV): m/z (%) ϭ 318 (6) [Mϩ]; 236 (5) [Mϩ Ϫ C6H10];
Eur. J. Org. Chem. 2002, 3294Ϫ3303
3299

U. Lüning, M. Abbass, F. Fahrenkrug
FULL PAPER
dry ethanol (5 mL) was added dropwise over 30 min to a refluxing ArCH2CH(COOEt)2], 4.24 (mc, 4 H, OCH2CH3), 6.53 (s, 2 H,
solution of compound 17b (200 mg, 0.465 mmol) in dry ethanol (50 ArH), 7.58, 7.59 (dd, J ϭ 4.4 Hz, J ϭ 8.1 Hz, 8-H; d, J ϭ 8.2 Hz,
mL). Heating was continued for 4 h. The volume was reduced to 5
mL and addition of water and neutralization with 2  aqueous
sodium hydroxide precipitated the product. The beige solid was
filtered off and dried in vacuo (Ͻ 1 mbar) in the presence of P2O5
to yield pure compound 17c as a beige powder, in 73% yield
3-H; 2 H), 7.79 (mc, 2 H, 5,6-H), 8.22, 8.24 (dd, J ϭ 1.8 Hz, J ϭ
8.1 Hz, 7-H; d, J ϭ 8.2 Hz, 4-H; 2 H), 9.18 (dd, J ϭ 1.8 Hz, J ϭ
4.4 Hz, 1 H, 9-H) ppm. 13C NMR (75 MHz, CDCl3): δ ϭ 14.1 (q,
OCH2CH3), 35.3 (t, ArCH2), 54.0 [d, ArCH2CH(COOEt)2], 56.0
(q, ArOCH3), 61.7 (t, OCH2CH3), 104.9 (d, 3Ј,5Ј-C), 118.6 (s, 1Ј-
(118 mg). M.p. Ͼ250 °C. IR (KBr): ν˜ ϭ 3363 (OϪH), 2935 (aliph. C), 122.6 (d, 8-C), 126.1, 126.2, 126.6 (3 d, 3,5,6-C), 127.4, 128.7
CϪH), 1581, 1450 (arom.), 1222, 1122 (CϪOϪC) cmϪ1. 1H NMR (2 s, 4a,6a-C), 135.5, 135.9 (2 d, 4,7-C), 140.1 (s, 4Ј-C), 146.2, 146.5
(300 MHz, [D6]DMSO): δ ϭ 3.64 (s, 6 H, ArOCH3), 4.62 (d, J ϭ (2 s, 10a,10b-C), 150.2 (d, 9-C), 155.5 (s, 2-C), 158.4 (s, 2Ј,6Ј-C),
5.8 Hz, 2 H, ArCH2OH), 5.41 (t, J ϭ 5.8 Hz, 1 H, ArCH2OH),
6.79 (s, 2 H, ArH), 7.59 (d, J ϭ 8.2 Hz, 1 H, 3-H), 7.75 (dd, J ϭ 487 (100) [Mϩ Ϫ H]; 470 (78) [Mϩ Ϫ H2O]; 459 (5) [Mϩ Ϫ C2H5];
4.3 Hz, J ϭ 8.1 Hz, 1 H, 8-H), 8.01 (mc, 2 H, 5,6-H), 8.45 (d, J ϭ
443 (14) [Mϩ Ϫ C2H5O]. C28H28N2O6 (488.54): calcd. C 68.84,
8.2 Hz, 1 H, 4-H), 8.50 (dd, J ϭ 1.8 Hz, J ϭ 8.1 Hz, 1 H, 7-H), H 8.78, N 5.73, C48H56N2O4·0.2H2O, calcd. C 68.34, H 5.82,
168.9 (s, COOEt) ppm. MS: (EI, 70 eV): m/z (%) ϭ 488 (78) [Mϩ];
9.03 (dd, J ϭ 1.8 Hz, J ϭ 4.3 Hz, 1 H, 9-H) ppm. MS: (EI, 70 eV):
N 5.69, found C 68.35, H 5.91, N 5.53.
m/z (%) ϭ 346 (48) [Mϩ]; 345 (100) [Mϩ Ϫ H]; 328 (62) [Mϩ
H2O]; 315 (17) [Mϩ Ϫ CH3O].
Ϫ
2-Chloro-9-(2,6-dimethoxyphenyl)-1,10-phenanthroline (17f): The
synthesis of compound 17f was carried out analogously to the syn-
thesis of 17a, starting from 803 µmol of 2,9-dichloro-1,10-phen-
anthroline (16b) and yielding 207 mg (73%) of 17f. M.p. Ͼ 250 °C.
IR (KBr): ν˜ ϭ 2837 (aliph. CϪH), 1590, 1471 (arom.), 1248, 1111
(CϪOϪC) cmϪ1. 1H NMR (300 MHz, CDCl3): δ ϭ 2.67 (H2O, ca.
1 H), 3.75 (s, 6 H, ArOCH3), 6.70 (d, J ϭ 8.3 Hz, 2 H, 3Ј,5Ј-H),
7.36 (t, J ϭ 8.3 Hz, 1 H, 4Ј-H), 7.55 [d, J ϭ 8.4 Hz, 1 H, 8-H (or
3-H)]; 7.67 [d, J ϭ 8.3 Hz, 1 H, 3ϪH (or 8-H)]; 7.77 (mc, 2 H, 5,6-
H), 8.15 [d, J ϭ 8.4 Hz, 1 H, 7-H (or 4-H)]; 8.23 [d, J ϭ 8.4 Hz, 1
H, 4-H (or 7-H)] ppm. 13C NMR (75 MHz, CDCl3): δ ϭ 56.4 (q,
ArOCH3), 104.9 (d, 3Ј,5Ј-C), 120.2 (s, 1Ј-C), 123.9, 125.3, 126.8,
127.0 (4 d, 3,5,6,8-C), 127.3, 128.8 (2 s, 4a,6a-C), 129.9 (d, 4Ј-C),
135.3, 138.6 (2 d, 4,7-C), 145.1, 146.4 (2 s, 10a,10b-C), 151.0 (s, 2-
C), 155.8 (s, 9-C), 158.5 (s, 2Ј,6Ј-C) ppm. MS: (EI, 70 eV): m/z
(%) ϭ 352, 350 (23, 53) [Mϩ]; 351, 349 (40, 100) [Mϩ Ϫ H]; 334,
332 (32, 46) [Mϩ Ϫ H2O]; 321, 319 (9, 18) [Mϩ Ϫ CH3O].
C20H15ClN2O2 (350.80): calcd. C 68.48, H 4.31, N 7.99,
C48H56N2O4·0.3 H2O, calcd. C 67.44, H 4.41, N 7.86, found
C 67.43, H 4.34, N 7.91.
2-[4-(Chloromethyl)-2,6-dimethoxyphenyl]-1,10-phenanthroline
(17d): 2-[2,6-Dimethoxy-4-(hydroxymethyl)phenyl]-1,10-phen-
anthroline (17c, 100 mg, 289 µmol) was dissolved in conc. hydro-
chloric acid (4 mL). The yellow solution was stirred for 16 h at 100
°C. After neutralization with solid sodium carbonate, the product
precipitated. The solid was filtered off, dissolved in 10 mL of
dichloromethane, and dried with magnesium sulfate. The solvent
was removed in vacuo and the residue was purified by filtration
through basic aluminium oxide (dichloromethane), yielding
87.0 mg (83%) of 17d.
The reaction was also carried out with 2-{2,6-dimethoxy-4-[(2-
tetrahydropyranyloxy)methyl]phenyl}-1,10-phenanthroline
(17b,
100 mg, 232 µmol) instead of compound 17c, yielding 54 mg (64%)
of 17d. M.p. 189 °C. IR (KBr): ν˜ ϭ 2934 (aliph. CϪH), 1585, 1456
(arom.), 1235, 1126 (CϪOϪC) cmϪ1
.
1H NMR (200 MHz,
CDCl3): δ ϭ 3.70 (s, 6 H, ArOCH3), 4.63 (s, 2 H, ArCH2Cl), 6.68
(s, 2 H, ArH), 7.58 (dd, J ϭ 4.4 Hz, J ϭ 8.0 Hz, 1 H, 8-H), 7.60
(d, J ϭ 8.2 Hz, 1 H, 3-H), 7.80 (mc, 2 H, 5,6-H), 8.23 (dd, J ϭ 1.7
Hz, J ϭ 8.0 Hz, 1 H, 7-H), 8.25 (d, J ϭ 8.2 Hz, 1 H, 4-H), 9.18
(dd, J ϭ 1.7 Hz, J ϭ 4.4 Hz, 1 H, 9-H) ppm. 13C NMR (75 MHz,
CDCl3): δ ϭ 46.8 (t, ArCH2Cl), 55.9 (q, ArOCH3), 104.5 (d, 3Ј,5Ј-
C), 119.2 (s, 1Ј-C), 122.8 (d, 8-C), 126.2, 126.3, 126.8 (3 d, 3,5,6-
C), 127.5, 128.8 (2 s, 4a,6a-C), 135.8, 137.1 (2 d, 4,7-C), 139.4 (s,
4Ј-C), 145.2 (s, 10a,10b-C), 149.3 (d, 9-C), 154.9 (s, 2-C), 158.3 (s,
2Ј,6Ј-C) ppm. MS: (EI, 70 eV): m/z (%) ϭ 366, 364 (27, 62) [Mϩ];
365, 363 (49, 100) [Mϩ Ϫ H]; 348, 346 (31, 66) [Mϩ Ϫ H2O]; 335,
333 (12, 18) [Mϩ Ϫ CH3O]; 329 (10) [Mϩ Ϫ Cl].
2-Chloro-9-[2,6-bis(pent-4-enoxy)phenyl]-1,10-phenanthroline
(17g): 2,6-Bis(pent-4-enoxy)benzeneboronic acid (15b, 96.0 mg,
331 mmol), tetrakis(triphenylphosphane)palladium(0) (35.0 mg,
30.0 µmol), and aqueous sodium carbonate (2 , 0.3 mL) were ad-
ded to
a solution of 2,9-dichloro-1,10-phenanthroline (16b,
75.0 mg, 301 µmol) in dimethoxyethane (20 mL). The reaction mix-
ture was heated under reflux for 16 h. After addition of water and
dichloromethane (20 mL each), the water layer was extracted with
dichloromethane (3 times, 30 mL each) and the combined organic
layer was washed with saturated aqueous sodium chloride. The
solvent was removed in vacuo, and the residue was purified by fil-
2-{2,6-Dimethoxy-4-[(2,2-bis(ethoxycarbonyl)ethyl]phenyl}-1,10-
phenanthroline (17e): Sodium hydride (60% dispersion in mineral
oil, 49.0 mg, 1.23 mmol, washed with n-pentane) was added to di- tration through basic aluminium oxide (dichloromethane) and by
ethyl malonate (10 mL). After the mixture had been stirred for
column chromatography (silica gel, dichloromethane/0.5% meth-
30 min, a solution of compound 17d (300 mg, 822 µmol) in dry
anol), and was then recrystallized from dichloromethane/n-hexane
N,N-dimethylformamide (5 mL) was added. The reaction mixture to yield 98 mg (71%) of 17g. M.p. 85Ϫ87 °C. IR (KBr): ν˜ ϭ 2932
was stirred for 16 h at 100 °C. The solvents were removed in vacuo,
and the residue was dissolved in dichloromethane and water (10
mL each). The water layer was extracted with dichloromethane (3
times, 10 mL each) and the combined organic layer was dried with
magnesium sulfate. The solvent was evaporated in vacuo, and the
residue was purified by column chromatography (basic aluminium
(aliph. CϪH), 1641 (aliph. CϭC), 1592, 1479, 1456 (arom.), 1107
(CϪOϪC) cmϪ1. 1H NMR (300 MHz, CDCl3): δ ϭ 1.66 (mc, 4 H,
OCH2CH2), 2.03 (mc, 4 H, CH2CHϭ), 4.01 (t, J ϭ 6.3 Hz, 4 H,
OCH2), 4.7Ϫ4.9 (m, 4 H, ϭCH2), 5.63 (tdd, Jt ϭ 6.6 Hz, Jd ϭ
9.6 Hz, Jd ϭ 17.7 Hz, 2 H, CHϭ), 6.68 (d, J ϭ 8.4 Hz, 4 H, 3Ј,5Ј-
H), 7.31 (t, J ϭ 8.4 Hz, 2 H, 4Ј-H), 7.56, 7.75 (2 d, J ϭ 8.4 Hz, 2 H,
oxide, dichloromethane) and recrystallization from cyclohexane/ 3,8-H), 7.76, 7.84 (2 d, J ϭ 8.8 Hz, 2 H, 5,6-H), 8.17, 8.22 (2 d, J ϭ
ethyl acetate, yielding 209 mg (52%). M.p. 136 °C. IR (KBr): ν˜ ϭ
8.4 Hz, 2 H, 4,7-H) ppm. 13C NMR (75 MHz, CDCl3): δ ϭ 28.4
2936 (aliph. CϪH), 1721 (CϭO), 1581, 1456 (arom.), 1242, 1126 (t, CH2CHϭ), 30.0 (t, OCH2CH2), 68.4 (t, OCH2), 106.1 (d, 3Ј,5Ј-
(CϪOϪC) cmϪ1 1H NMR (300 MHz, CDCl3): δ ϭ 1.31 (t, J ϭ C), 114.5 (t, ϭCH2), 120.7 (s, 1Ј-C), 123.8, 125.1, 127.0, 127.1,
7.1 Hz, 6 H, OCH2CH3), 2.20 (H2O, ca. 1 H), 3.28 (d, J ϭ 7.7 Hz, 130.0, 134.6, 138.5 (7 d, 4Ј,3,4,5,6,7,8-C), 127.2, 127.5 (2 s, 4a,6a-
.
2 H, ArCH2), 3.68 (s, 6 H, ArOCH3), 3.71 [t, J ϭ 7.7 Hz, 1 H,
C), 138.2 (d, CHϭ), 144.8, 146.3 (2 s, 10a,10b-C), 150.9, 155.7 (2 s,
3300
Eur. J. Org. Chem. 2002, 3294Ϫ3303

A Facile Route to Aryl-Substituted 1,10-Phenanthrolines
FULL PAPER
2,9-C), 158.1 (2Ј,6Ј-C) ppm. MS: (EI, 70 eV): m/z (%) ϭ 460, 458
(26, 63) [Mϩ]; 419, 417 (34, 100) [Mϩ Ϫ C3H5]; 405, 403 (29, 77)
(CϪOϪC) cmϪ1
.
1H NMR (300 MHz, CDCl3): δ ϭ 1.27 (t, J ϭ
7.1 Hz, 6 H, OCH2CH3), 2.41 (H2O, ca. 1 H), 3.24 (d, J ϭ 7.7 Hz,
[Mϩ Ϫ C4H7]; 391, 389 (7, 18) [Mϩ Ϫ C5H9]. C28H27ClN2O2 2 H, ArCH2), 3.69 (t, J ϭ 7.7 Hz, 1 H, ArCH2CH(COOEt)2], 3.70,
(458.99): calcd. C 73.27, H 5.93, N 6.10; found C 73.19, H 6.09,
N 5.98.
3.72 (2 s, 12 H, ArOCH3), 4.21 (mc, 4 H, OCH2CH3), 6.51 (s, 2 H,
3Ј,5Ј-H), 6.65 (d, J ϭ 8.4 Hz, 2 H, 3ЈЈ,5ЈЈ-H), 7.30 (t, J ϭ 8.4 Hz, 1
H, 4ЈЈ-H), 7.59, 7.62 (2 d, J ϭ 8.2 Hz, 2 H, 3,8-H), 7.79 (s, 2 H,
5,6-H), 8.22, 8.23 (2 d, J ϭ 8.2 Hz, 1 H, 4,7-H) ppm. 13C NMR
(75 MHz, CDCl3): δ ϭ 14.1 (q, OCH2CH3), 35.2 (t, ArCH2), 53.9
[d, ArCH2CH(COOEt)2], 56.4, 56.4 (2 q, ArOCH3), 61.6 (t,
OCH2CH3), 105.0, 105.7 (2 d, 3Ј,5Ј,3ЈЈ,5ЈЈ-C), 119.2, 120.7 (2 s,
1Ј,1ЈЈ-C), 125.9, 126.0, 126.2 (3 d, 3,5,6,8-C), 127.5 (s, 4a,6a-C),
129.7 (d, 4ЈЈ-C), 135.3, 135.4 (2 d, 4,7-C), 140.1 (s, 4Ј-C), 146.3 (s,
10a,10b-C), 154.7, 154.9 (2 s, 2,9-C), 158.4, 158.5 (2 s, 2Ј,6Ј,2ЈЈ,6ЈЈ-
C), 168.9 (s, COOEt) ppm. MS: (EI, 70 eV): m/z (%) ϭ 642 (92)
[Mϩ]; 623 (100) [Mϩ Ϫ H]; 606 (45) [Mϩ Ϫ H2O]; 593 (12) [Mϩ
Ϫ CH3O]; 579 (11) [Mϩ Ϫ CHO2]. C36H36N2O8 (624.69): calcd.
C 69.22, H 5.81, N 4.48, C29H25N2O4·0.5 H2O, calcd. C 68.23,
H 5.89, N 4.42, found C 68.24, H 6.01, N 4.30.
2,9-Bis(2,6-dimethoxyphenyl)-1,10-phenanthroline (18a): The syn-
thesis of compound 18a was carried out analogously to the syn-
thesis of 17a, with 2,9-dichloro-1,10-phenanthroline (16b, 803
µmol) and 2 equiv. of compound 3. Refluxing for 2 days gave
300 mg (83%) of 18a. The spectroscopic data were in accordance
with ref.[11]
9-(2,6-Dimethoxyphenyl)-2-{2,6-dimethoxy-4-[(2-tetrahydropyranyl-
oxy)methyl]phenyl}-1,10-phenanthroline (18b): The synthesis of
compound 18b was carried out analogously to the synthesis of 17b,
with 2-chloro-9-(2,6-dimethoxyphenyl)-1,10-phenanthroline (854
µmol, 17f). Refluxing for 2 days gave 283 mg (88%) of 18b. M.p.
Ͼ 250 °C. IR (KBr): ν˜ ϭ 2939 (aliph. CϪH), 1582, 1472 (arom.),
1247, 1108 (CϪOϪC) cmϪ1 1H NMR (300 MHz, CDCl3): δ ϭ
.
2,9-Bis[2,6-bis(but-3-enoxy)phenyl]-1,10-phenanthroline (18f): 2,9-
Bis(but-4-enoxy)benzeneboronic acid (15a, 263 mg, 1.00 mmol),
tetrakis(triphenylphosphane)palladium(0) (46.0 mg, 40.0 µmol),
barium hydroxide (258 mg, 1.51 mmol), and water (2 mL) were ad-
ded to a solution of 2,9-dichloro-1,10-phenanthroline (16b, 100 mg,
402 µmol) in dimethoxyethane (20 mL). The reaction mixture was
heated under reflux for 16 h. After the addition of water and
dichloromethane (20 mL each), the water layer was extracted with
dichloromethane (3 times, 30 mL each) and the combined organic
layer was washed with saturated aqueous sodium chloride. The
solvent was removed in vacuo, and the residue was purified by fil-
tration through basic aluminium oxide (dichloromethane) and
recrystallized from dichloromethane/n-hexane, yielding 191 mg
(78%) of 18f. M.p. 142-143 °C. IR (KBr): ν˜ ϭ 3448 (OϪH, mois-
ture), 3070 (arom. CϪH), 2938, 2872 (aliph. CϪH), 1642 (aliph.
1.5Ϫ1.9 (m, 6 H, CH2), 3.5Ϫ3.6 (m, 1 H, CH2O), 3.72 (s, 6 H,
ArOCH3), 3.73 (s, 6 H, ArOCH3), 3.9Ϫ4.0 (m, 1 H, CH2O), 4.55
(d, J ϭ 12.3 Hz, 1 H, ArCH2O), 4.72 (dd, J ϭ 2.9 Hz, J ϭ 4.4 Hz,
1 H, OCHO), 4.79 (d, J ϭ 12.3 Hz, 1 H, ArCH2O), 6.65 (d, J ϭ
8.4 Hz, 2 H, 3ЈЈ,5ЈЈ-H), 6.67 (s, 2 H, 3Ј,5Ј-H), 7.25 (s, 1 H, CHCl3),
7.30 (t, J ϭ 8.4 Hz, 1 H, 4ЈЈ-H), 7.61, 7.62 (2 d, J ϭ 8.2 Hz, 2 H,
3,8-H), 7.80 (mc, 2 H, 5,6-H), 8.23, 8.23 (2 d, J ϭ 8.2 Hz, 2 H, 4,7-
H) ppm. MS: (EI, 70 eV): m/z (%) ϭ 566 (100) [Mϩ]; 565 (96) [Mϩ
Ϫ H]; 548 (49) [Mϩ Ϫ H2O]; 535 (17) [Mϩ Ϫ CH3O]; 481 (13) [Mϩ
Ϫ C5H9O]; 465 (17) [Mϩ Ϫ C5H9O2]. C34H34N2O6 (566.65): calcd.
C 72.07, H 6.05, N 4.94, C34H34N2O6·0.75 CHCl3, calcd. C 63.61,
H 5.34, N 4.27, found C 63.85, H 4.98, N 4.14.
2-(4-Chloromethyl-2,6-dimethoxyphenyl)-9-(2,6-dimethoxyphenyl)-
1,10-phenanthroline (18d): The synthesis of compound 18d was car-
ried out analogously to the synthesis of 17d, with 9-(2,6-dimethoxy-
phenyl)-2-{2,6-dimethoxy-5-[(2-tetrahydropyranyloxy)methyl]-
phenyl}-1,10-phenanthroline (18b, 176 µmol) and yielding 72 mg
(82%) of 18c. M.p. Ͼ 250 °C. IR (KBr): ν˜ ϭ 2935 (aliph. CϪH),
CϭC), 1593, 1459 (arom.), 1102 (CϪOϪC) cmϪ1 1H NMR
.
(300 MHz, CDCl3): δ ϭ 2.25 (qt, Jq ϭ 6.8 Hz, Jt ഠ 1.3 Hz, 8 H,
OCH2CH2), 3.96 (t, J ϭ 6.8 Hz, 8 H, OCH2), 4.7Ϫ4.9, (m, 8 H,
ϭCH2), 5.60 (tdd, Jt ϭ 6.8 Hz, Jd ϭ 10.2 Hz, Jd ϭ 17.2 Hz, 4 H,
CHϭ), 6.63 (d, J ϭ 8.4 Hz, 4 H, 3Ј,3ЈЈ,5Ј,5ЈЈ-H), 7.25 (t, J ϭ
8.4 Hz, 2 H, 4Ј,4ЈЈ-H), 7.62 (d, J ϭ 8.2 Hz, 2 H, 3,8-H), 7.81 (s,
2 H, 5,6-H), 8.20 (d, J ϭ 8.2 Hz, 2 H, 4,7-H) ppm. 13C NMR
(125 MHz, CDCl3): δ ϭ 33.5 (t, OCH2CH2), 68.5 (t, OCH2), 106.3
(d, 3Ј,3ЈЈ,5Ј,5ЈЈ-C), 116.4 (t, ϭCH2), 121.4 (s, 1Ј,1ЈЈ-C), 126.0, 126.1
(2 d, 3,5,6,8-C), 127.2 (s, 4a,6a-C), 129.5 (d, 4Ј,4ЈЈ-C), 134.7, 134.8
(2 d, 4,7-C, CHϭ), 146.2 (s, 10a,10b-C), 154.8 (s, 2,9-C), 157.8 (s,
2Ј,2ЈЈ,6Ј,6ЈЈ-C). Assignment was confirmed by HMBC and HSQC.
MS: (EI, 70 eV): m/z (%) ϭ 612 (100) [Mϩ]; 571 (88) [Mϩ Ϫ C3H5];
557 (26) [Mϩ Ϫ C4H7]. C40H40N2O4 (612.77), calcd. C 78.41,
H 6.58, N 4.57, C40H40N2O4·0.2 H2O, calcd. C 77.95, H 6.61,
N 4.55, found C 77.87, H 6.68, N 4.48.
1585, 1470 (arom.), 1248, 1110 (CϪOϪC) cmϪ1 1H NMR
.
(300 MHz, CDCl3): δ ϭ 3.72, 3.73 (2 s, 12 H, ArOCH3), 6.65 (d,
J ϭ 8.4 Hz, 2 H, 3ЈЈ,5ЈЈ-H), 6.67 (s, 2 H, 3Ј,5Ј-H), 7.24 (s, ca. 0.5
H, CHCl3), 7.30 (t, J ϭ 8.4 Hz, 1 H, 4ЈЈ-H), 7.60, 7.63 (2 d, J ϭ
8.2 Hz, 2 H, 3,8-H), 7.81 (s, 2 H, 5,6-H), 8.24 (d, J ϭ 8.2 Hz, 2 H,
4,7-H) ppm. 13C NMR (75 MHz, CDCl3): δ ϭ 46.7 (t, ArCH2Cl),
56.0 (2 q, ArOCH3), 104.5, 104.8 (2 d, 3Ј,5Ј,3ЈЈ,5ЈЈ-C), 119.5, 119.6
(2 s, 1Ј,1ЈЈ-C), 125.9, 126.1, 126.2, 126.4 (4 d, 3,5,6,8-C), 127.6 (2
s, 4a,6a-C), 129.9 (d, 4ЈЈ-C), 135.7, 135.8 (2 d, 4,7-C), 139.3 (s, 4Ј-
C), 145.9 (2 s, 10a,10b-C), 154.3, 154.7 (2 s, 2,9-C), 158.2, 158.3 (2
s, 2Ј,6Ј,2ЈЈ,6ЈЈ-C) ppm. MS: (EI, 70 eV): m/z (%) ϭ 500, 502 (53,
23) [Mϩ]; 499, 501 (100, 44) [Mϩ Ϫ H]; 482, 484 (28, 16) [Mϩ
H2O]; 481, 483 (28, 12) [Mϩ Ϫ H Ϫ H2O]; 465 (8) [Mϩ
Ϫ
Ϫ
2,9-Bis[2,6-bis(pent-4-enoxy)phenyl]-1,10-phenanthroline (18g): 2,9-
Diiodo-1,10-phenanthroline (16c, 200 mg, 462 µmol) was dissolved
in dimethoxyethane (40 mL). After addition of 2,9-bis(pent-4-enoxy)-
benzeneboronic acid (15b, 336 mg, 1.16 mmol), tetrabutylammo-
Cl]. C29H25ClN2O4 (500.98): calcd. C 69.53, H 5.03, N 5.59,
C29H25ClN2O4·0.5 CHCl3, calcd. C 63.20, H 4.58, N 5.00, found
C 63.53, H 4.62, N 4.84.
2-{2,6-Dimethoxy-4-[(2,2-bis(ethoxycarbonyl)ethyl]phenyl}-9- nium fluoride (732 mg, 2.32 mmol), and tetrakis(triphenylphos-
(2,6-dimethoxyphenyl)-1,10-phenanthroline (18e): The synthesis of
compound 18e was carried out analogously to the synthesis of 17e,
with 2-(4-chloromethyl-2,6-dimethoxyphenyl)-9-(2,6-dimethoxy-
phane)palladium(0) (54.0 mg, 46.0 µmol), the reaction mixture was
heated under reflux for 16 h. After the addition of water and
dichloromethane (20 mL each), the water layer was extracted with
phenyl)-1,10-phenanthroline (18d, 299 µmol). The product was dichloromethane (3 times, 30 mL each) and the combined organic
purified by chromatography (silica gel, dichloromethane/2% meth-
anol) and filtration through basic aluminium oxide (dichlorome-
layer was washed with saturated aqueous sodium chloride. The
solvent was removed in vacuo and the residue was purified by fil-
thane), yielding 89 mg (48%) of 18e. M.p. Ͼ 250 °C. IR (KBr): ν˜ ϭ tration through basic aluminium oxide (dichloromethane) and
2936 (aliph. CϪH), 1746 (CϭO), 1579, 1472 (arom.), 1249, 1112
Eur. J. Org. Chem. 2002, 3294Ϫ3303
recrystallized from dichloromethane/n-hexane, yielding 273 mg
3301

U. Lüning, M. Abbass, F. Fahrenkrug
FULL PAPER
(88%) of 18g. Ϫ The reaction analogous to that used for the pre-
paration of 18f, but with 2,9-dichloro-1,10-phenanthroline
(1.61 mmol) and barium hydroxide as the base, gave 988 mg (92%)
of 18g. M.p. 111 °C. IR (KBr): ν˜ ϭ 3072 (arom. CϪH), 2936, 2871
(300 MHz, CDCl3): δ ϭ 1.56 (mc, 4 H, OCH2CH2CH2CHϭ), 1.85
(mc, 4 H, O(CH2)2CH2CHϭ), 2.25 (qt, Jq ϭ 6.8 Hz, Jt ഠ 1.3 Hz,
4 H, OCH2CH2CHϭ), 3.35 (br. s, 0.6 H, OH), 3.91, 3.97 (2 t, J ϭ
6.4, J ϭ 6.7, 8 H, OCH2), 4.7Ϫ4.9 (m, 8 H, ϭCH2), 5.5Ϫ5.7 (m,
(aliph. CϪH), 1638 (aliph. CϭC), 1596, 1459 (arom.), 1102 4 H, CHϭ), 6.61, 6.63 (2 d, J ϭ 8.4, J ϭ 8.4, 4 H, 3Ј,3ЈЈ,5Ј,5ЈЈ-H),
(CϪOϪC) cmϪ1. 1H NMR (300 MHz, CDCl3): δ ϭ 1.58 (mc, 8 H, 7.25, 7.26 (2 t, J ϭ 8.4 Hz, 2 H, 4Ј,4ЈЈ-H), 7.61, 7.62 (2 d, J ϭ
OCH2CH2), 1.87 (mc, 8 H, CH2CHϭ), 3.92 (t, J ϭ 6.4 Hz, 8 H, 8.2 Hz, 2 H, 3,8-H), 7.80 (s, 2 H, 5,6-H), 8.19, 8.22 (2 d, J ϭ 8.2 Hz,
OCH2), 4.7Ϫ4.8 (m, 8 H, ϭCH2), 5.57 (tdd, Jt ϭ 6.7 Hz, Jd ϭ 2 H, 4,7-H) ppm. 13C NMR (75 MHz, CDCl3): δ ϭ 28.2 [t,
10.3 Hz, Jd ϭ 17.0 Hz, 4 H, CHϭ), 6.61 (d, J ϭ 8.4 Hz, 4 H,
3Ј,3ЈЈ,5Ј,5ЈЈ-H), 7.23 (t, J ϭ 8.4 Hz, 2 H, 4Ј,4ЈЈ-H), 7.61 (d, J ϭ
O(CH2)2CH2CHϭ], 29.9 (t, OCH2CH2CH2CHϭ), 33.5 (t,
OCH2CH2CHϭ), 68.1, 68.4 (2 t, OCH2), 105.2, 106.2 (2 d,
8.2 Hz, 2 H, 3,8-H), 7.80 (s, 2 H, 5,6-H), 8.21 (d, J ϭ 8.2 Hz, 2 H, 3Ј,3ЈЈ,5Ј,5ЈЈ-C), 114.6, 116.4 (2 t, ϭCH2), 121.0, 121.0 (2 s, 1Ј,1ЈЈ-
4,7-H) ppm. 13C NMR (75 MHz, CDCl3): δ ϭ 28.2 (t, CH2CHϭ),
C), 125.9, 126.1, 126.1, 126.2 (4 d, 3,5,6,8-C), 127.3, 127.3 (2 s,
29.9 (t, OCH2CH2), 68.5 (t, OCH2), 106.3 (d, 3Ј,3ЈЈ,5Ј,5ЈЈ-C), 114.6 4a,6a-C), 129.6, 129.6 (2 d, 4Ј,4ЈЈ-C), 134.7, 138.0 (2 d, CHϭ),
(t, ϭCH2), 121.9 (s, 1Ј,1ЈЈ), 125.9, 126.0 (2 d, 3,5,6,8-C), 127.2 (s, 134.9, 135.0 (2 d, 4,7-C), 146.0, 146.1 (2 s, 10a,10b-C), 154.8, 155.1
4a,6a-C), 129.3 (d, 4Ј,4ЈЈ-C), 134.7 (d, 4,7-C), 138.1 (d, CHϭ), (2 s, 2,9-C), 157.7, 157.8 (2 s, 2Ј,2ЈЈ,6Ј,6ЈЈ-C) ppm. MS: (EI, 70 eV):
146.4 (s, 10a,10b-C), 155.0 (s, 2,9-C), 158.0 (2Ј,2ЈЈ,6Ј,6ЈЈ-C) ppm.
m/z (%) ϭ 640 (100) [Mϩ]; 599 (78) [Mϩ Ϫ C3H5]; 585 (47) [Mϩ
MS: (EI, 70 eV): m/z (%) ϭ 668 (100) [Mϩ]; 627 (97) [Mϩ Ϫ C3H5]; Ϫ C4H7]; 532 (11) [Mϩ Ϫ C8H14]. C42H44N2O4 (640.82), calcd.
613 (74) [Mϩ Ϫ C4H7]; 599 (20) [Mϩ Ϫ C5H9]. C44H48N2O4 C 78.72, H 6.92, N 4.37, C42H44N2O4·0.3 H2O, calcd. C 78.06,
(668.36): calcd. C 79.01, H 7.23, N 4.19; found C 78.88, H 7.06,
N 4.09.
H 6.96, N 4.34; found C 78.12, H 7.05, N 4.20.
2-[2,6-Bis(hex-5-enoxy)phenyl]-9-[2,6-bis(pent-4-enoxy)phenyl]-
1,10-phenanthroline (18j): The synthesis of compound 18j was car-
ried out analogously to that of 18i, with 2,6-bis(hex-5-enoxy)ben-
zeneboronic acid (15c, 736 µmol), yielding 450 mg (88%) of 18j.
M.p. 110Ϫ111 °C. IR (KBr): ν˜ ϭ 3429 (OϪH, moisture), 2934 (al-
iph. CϪH), 1639 (aliph. CϭC), 1596, 1460 (arom.), 1104
2,9-Bis[2,6-bis(hex-5-enoxy)phenyl]-1,10-phenanthroline (18h): The
synthesis of compound 18h was carried out analogously to that of
18g, with 2,6-bis(hex-5-enoxy)benzeneboronic acid (15c, 254 µmol),
yielding 162 mg (88%) of 18h. Ϫ The reaction analogous to that
used for the preparation of 18f, but with 2,9-dichloro-1,10-phen-
anthroline (1.61 mmol) and barium hydroxide as the base, gave
1.17 g (73%) of 18h. M.p. 108Ϫ109 °C. IR (KBr): ν˜ ϭ 3072 (arom.
CϪH), 2934 (aliph. CϪH), 1639 (aliph. CϭC), 1596, 1458 (arom.),
1104 (CϪOϪC) cmϪ1. 1H NMR (300 MHz, CDCl3): δ ϭ 1.21 (mc,
8 H, OCH2CH2CH2), 1.49 (mc, 8 H, OCH2CH2), 1.80 (mc, 8 H,
CH2CHϭ), 3.91 (t, J ϭ 6.4 Hz, 8 H, OCH2), 4.7Ϫ4.8 (m, 8 H,
ϭCH2), 5.30 (s, 0.10 H, CH2Cl2), 5.53 (tdd, Jt ϭ 6.6 Hz, Jd ϭ
10.4 Hz, Jd ϭ 16.9 Hz, 4 H, CHϭ), 6.61 (d, J ϭ 8.4 Hz, 4 H,
3Ј,3ЈЈ,5Ј,5ЈЈ-H), 7.24 (t, J ϭ 8.4 Hz, 2 H, 4Ј,4ЈЈ-H), 7.60 (d, J ϭ
8.2 Hz, 2 H, 3,8-H), 7.80 (s, 2 H, 5,6-H), 8.19 (d, J ϭ 8.2 Hz, 2 H,
(CϪOϪC) cmϪ1 1H NMR (300 MHz, CDCl3): δ ϭ 1.1Ϫ1.3 [m,
.
4 H, O(CH2)2CH2CH2CHϭ), 1.4Ϫ1.65 (m, 8 H, OCH2CH2),
1.75Ϫ1.95 (m, 8 H, CH2CHϭ), 3.35 (br. s, 0.4 H, OH), 3.92 (mc,
8 H, OCH2), 4.7Ϫ4.9 (m, 8 H, ϭCH2), 5.55 (mc, 4 H, CHϭ), 6.60,
6.61 (2 d, J ϭ 8.4, J ϭ 8.4, 4 H, 3Ј,3ЈЈ,5Ј,5ЈЈ-H), 7.24 (t, J ϭ 8.4 Hz,
2 H, 4Ј,4ЈЈ-H), 7.59, 7.62 (2 d, J ϭ 8.2 Hz, 2 H, 3,8-H), 7.80 (s, 2 H,
5,6-H), 8.19, 8.21 (2 d, J ϭ 8.2 Hz, 2 H, 4,7-H) ppm. 13C NMR
(75 MHz, CDCl3): δ ϭ 25.0 [t, O(CH2)2CH2CH2CHϭ], 28.2, 28.4
[2 t, O(CH2)2CH2CHϭ, OCH2CH2(CH2)2CHϭ], 29.9 (t,
OCH2CH2CH2CHϭ), 33.1 [t, O(CH2)3CH2CHϭ], 68.4, 68.9 (2 t,
OCH2), 106.1, 106.1 (2 d, 3Ј,3ЈЈ,5Ј,5ЈЈ-C), 114.1, 114.6 (2 t, ϭCH2),
121.6 (s, 1Ј,1ЈЈ-C), 125.9, 126.0, 126.1 (3 d, 3,5,6,8-C), 127.2 (s,
4a,6a-C), 129.4, 129.4 (2 d, 4Ј,4ЈЈ-C), 134.7, 134.8 (2 d, 4,7-C),
138.1, 138.6 (2 d, CHϭ), 146.4 (s, 10a,10b-C), 155.0, 155.1 (2 s, 2,9-
C), 158.0, 158.0 (2 s, 2Ј,2ЈЈ,6Ј,6ЈЈ-C) ppm. MS: (EI, 70 eV): m/z
4,7-H) ppm. 13C NMR (75 MHz, CDCl3):
δ ϭ 25.0 (t,
OCH2CH2CH2), 28.4 (t, OCH2CH2), 33.1 (t, CH2CHϭ), 69.0 (t,
OCH2), 106.2 (d, 3Ј,3ЈЈ,5Ј,5ЈЈ-C), 114.2 (t, ϭCH2), 121.8 (s, 1Ј,1ЈЈ-
C), 125.9, 126.0 (2 d, 3,5,6,8-C), 127.3 (s, 4a,6a-C), 129.3 (d, 4Ј,4ЈЈ-
C), 134.7 (d, 4,7-C), 138.6 (d, CHϭ), 146.4 (s, 10a,10b-C), 155.1
(s, 2,9-C), 158.1 (2Ј,2ЈЈ,6Ј,6ЈЈ-C) ppm. MS: (EI, 70 eV): m/z (%) ϭ
724 (100) [Mϩ]; 669 (12) [Mϩ Ϫ C4H7]; 655 (58) [Mϩ Ϫ C5H9]; 641
(81) [Mϩ Ϫ C6H11]. C48H56N2O4 (724.99): calcd. C 79.52, H 7.79,
N 3.86, C48H56N2O4·0.1CH2Cl2, calcd. C 78.77, H 7.72, N 3.82,
found C 78.68, H 7.72, N 3.70.
(%) ϭ 696 (100) [Mϩ]; 655 (52) [Mϩ Ϫ C3H5]; 641 (47) [Mϩ
Ϫ
C4H7]; 627 (40) [Mϩ C5H9]; 613 (43) [Mϩ
Ϫ
Ϫ
C6H11].
C46H52N2O4 (696.93), calcd. C 79.28, H 7.52, N 4.02,
C46H52N2O4·0.2H2O, calcd. C 78.87, H 7.54, N 4.00; found
C 78.89, H 7.43, N 3.84.
2-[2,6-Bis(but-3-enoxy)phenyl]-9-[2,6-bis(pent-4-enoxy)phenyl]-
1,10-phenanthroline (18i): 2,9-Bis(but-3-enoxy)benzeneboronic acid
(15a, 357 mg, 1.36 mmol), tetrakis(triphenylphosphane)pallad-
ium(0) (126 mg, 109 µmol), barium hydroxide (350 mg, 2.04 mmol),
and water (12.5 mL) were added to a solution of 2-chloro-9-[2,6-
Acknowledgments
We would like to thank Dr. Martin Hagen for his inspiration and
for providing us with starting material, and we thank Prof. Dr.
Michael Göbel, Johann-Wolfgang-Goethe-Universität Frankfurt,
for his very kind and prompt help in preparing boronic acids.
bis(pent-4-enoxy)phenyl]-1,10-phenanthroline
(17g,
500 mg,
1.09 mmol) in dimethoxyethane (50 mL). The reaction mixture was
heated under reflux for 16 h. After the addition of water and
dichloromethane (50 mL each), the water layer was extracted with
dichloromethane (3 times, 50 mL each) and the combined organic
layer was washed with saturated aqueous sodium chloride solution.
The solvent was removed in vacuo and the residue was purified by
filtration through basic aluminium oxide (dichloromethane) and
was recrystallized from dichloromethane/n-hexane yielding 456 mg
(65%) of 18i. M.p. 96Ϫ98 °C. IR (KBr): ν˜ ϭ 3476 (OϪH, mois-
ture), 3075 (arom. CϪH), 2938, 2871 (aliph. CϪH), 1640, 1620
(aliph. CϭC), 1593, 1458 (arom.), 1101 (CϪOϪC) cmϪ1. 1H NMR
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[20]
Received February 18, 2002
[O02091]
Eur. J. Org. Chem. 2002, 3294Ϫ3303
3303