A simple route to derivatives of benzo[j]fluoranthene

Article abstract of DOI:10.1016/j.tet.2013.11.029

3,6,8,11-Tetramethoxybenzo[j]fluoranthene can be made from 1,6-dimethoxynaphthalene in a one-pot ferric chloride oxidation/methanol reduction procedure. The reaction is tolerant of the presence of substituents in the 7-position of the naphthalene nucleus and provides a quick and easy route to these particular benzo[j]fluoranthenes. The reactions presumably proceed through initial formation of a bond between the 4-positions of two naphthalene molecules followed by closure of the five-membered ring. Indeed in one case some 4,4′-binaphthyl was isolated from the reaction mixture and it was generally found that better yields of the benzo[j]fluoranthrenes were obtained starting from the 4,4′-binaphthyl rather than by using the naphthalene as the starting material. In an analogous manner to the ring-closure of the 4,4′-binaphthyls, starting from a hexakisalkoxyphenylnaphthalene, a hexakisalkoxyfluoranthene could be obtained.

Full text of DOI:10.1016/j.tet.2013.11.029

Tetrahedron 70 (2014) 67e74
Contents lists available at ScienceDirect
Tetrahedron
journal homepage: www.elsevier.com/locate/tet
A simple route to derivatives of benzo[j]fluoranthene
y
Daniel J. Tate , Mohamed Abdelbasit, Colin A. Kilner, Helena J. Shepherd,
Stuart L. Warriner, Richard J. Bushby *
School of Chemistry, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK
a r t i c l e i n f o
a b s t r a c t
Article history:
3,6,8,11-Tetramethoxybenzo[j]fluoranthene can be made from 1,6-dimethoxynaphthalene in a one-pot
ferric chloride oxidation/methanol reduction procedure. The reaction is tolerant of the presence of
substituents in the 7-position of the naphthalene nucleus and provides a quick and easy route to these
particular benzo[j]fluoranthenes. The reactions presumably proceed through initial formation of a bond
between the 4-positions of two naphthalene molecules followed by closure of the five-membered ring.
Received 11 September 2013
Received in revised form 28 October 2013
Accepted 12 November 2013
Available online 16 November 2013
0
Indeed in one case some 4,4 -binaphthyl was isolated from the reaction mixture and it was generally
Keywords:
Scholl reaction
Fluoranthene
Benzo[j]fluoranthene
Ferric chloride
0
found that better yields of the benzo[j]fluoranthrenes were obtained starting from the 4,4 -binaphthyl
rather than by using the naphthalene as the starting material. In an analogous manner to the ring-closure
0
of the 4,4 -binaphthyls, starting from a hexakisalkoxyphenylnaphthalene, a hexakisalkoxyfluoranthene
could be obtained.
Ó 2013 Elsevier Ltd. All rights reserved.
1
. Introduction
allowing phenols to be obtained directly from this one-pot process;
12
despite the strongly oxidizing nature of first step. Very high yields
can be obtained but this is dependent on the use of an excess of the
oxidant, the use of a non-nucleophilic solvent and the use of a re-
ductive, non-aqueous workup. Aqueous solvents and aqueous
workups usually result in mixtures of ring-hydroxylation products
and quinones, both of which arise ultimately from attack of water
on cationic intermediates. Although strong acids (most often TFA or
Studies of the mechanism of arylearyl oxidative coupling show
that, under strongly oxidizing conditions, what is finally produced
1
2
is very often a solution of the radical cation or polycation of the
desired product, which has to be reduced back to the neutral
molecule. This understanding underlays the development of a two-
step version of the Scholl reaction, in which excess ferric chloride in
dichloromethane is used as the oxidant in the usual way, but the
sulfuric acid) have sometimes been added to the reaction medium
3
5b,12
reaction mixture is worked up reductively with methanol. This
to suppress dealkylation,
this is unnecessary since the mixture
protocol has mainly been used in the liquid crystal field where it
has proved important in the synthesis of alkoxy substituted bi-
phenyls4 (dimerization of benzene derivatives), symmetrically
rapidly becomes highly acidic through the HCl that is evolved.
2. Results and discussion
5
substituted triphenylenes (trimerization of benzene derivatives),
unsymmetrically substituted triphenylenes (regiospecific cross-
coupling of benzene and biphenyl derivatives) and systems with
In the search for new applications for this protocol we in-
vestigated the oxidative dimerization of a variety of methox-
ynaphthalene derivatives and were surprised to find that 1,6-
dimethoxynaphthalene 1a (Scheme 1) gave a bright yellow crys-
talline ‘dimer’ [C20H (OMe) ] showing three aromatic methoxy
6
more extended polynuclear aromatic cores (mostly examples of
7
variants of the ortho-terphenyl to triphenylene reaction). Variants
8
have been introduced using vanadium oxychloride, molybde-
8
4
9
10
1
num(V) chloride, ferric chloride/alumina or ferric chloride/ni-
tromethane11 as the oxidant. Methoxy and most primary alkoxy
substituents survive these reaction conditions but iso-propoxy
substituents are cleaved (probably during the methanol workup)
signals (6H,3H,3H) in the H NMR spectrum together with two 1H
singlets and six 1H doublets between 6.7 and 8.2. A single crystal
d
X-ray crystallographic study showed this product to be 3,6,8,11-
tetramethoxybenzo[j]fluoranthene 2a (Fig 1).
Although the yield obtained from dimethoxynaphthalene was
not high (up to 45% after chromatography and recrystallization and
using an optimized 6e8 M equiv of ferric chloride) this reaction
provides a very simple entry to some unusual benzo[j]fluoranthene
derivatives. In general, although there are many convenient
*
Corresponding author. Tel.: þ44 (0113) 3436509; e-mail address: R.J.Bushby@
leeds.ac.uk (R.J. Bushby).
y
Present address: Organic Materials Innovation Centre, School of Chemistry,
13
University of Manchester, Oxford Road, Manchester M13 9PL, UK.
routes to benzo[j]fluoranthene itself, those for ring-substituted
0
040-4020/$ e see front matter Ó 2013 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.tet.2013.11.029

68
D.J. Tate et al. / Tetrahedron 70 (2014) 67e74
OMe
OMe
OMe
X
MeO
Br
OMe
X
OMe
1. FeCl
3
/DCM
MeO
OMe
Br
2. MeOH
X
MeO
OMe
1
1
1
1
1
a) X = H
2a) X = H, 30-45%
2b) X = I, 0%
3), 60%
b) X = I
c) X = Br
2c) X = Br, 25%
d) X = C
6
H
4
OMe
2d) X = C H OMe, 0%
6
4
e) X = OMe
2e) X = OMe, 42-65%
Scheme 1. Oxidative dimerization of derivatives of 1,6-dimethoxynaphthalene.
Fig. 1. (a) X-ray crystallographic structure of 3,6,8,11-tetramethoxybenzo[j]fluoranthene 2a (solvent molecules omitted for clarity, atomic displacement parameters drawn at 50%
probability) (b) Structure rotated to display the planar nature of the aromatic core. C: dark grey, O: black, H: light grey.
derivatives often involve many steps.13c,14 In an attempt to extend
the scope of the synthesis we have investigated a series of 7-
substituted derivatives of 1,6-dimethoxynaphthalene and the re-
sults of these studies are summarized in Scheme 1.
In terms of the starting materials used in this study, the 7-
iodonaphthalene 1b is readily obtained by regiospecific lithiation
dimethoxynaphthalene with N-iodosuccinimide and catalytic TFA
21
(78%), converted to the boronic ester 5 by a palladium mediated
reaction with pinacol borane (84%) and the binaphthyl 6 obtained
by coupling 4 and 5 under standard Suzuki conditions (89%). Per-
0
haps the most persuasive evidence for the idea that 4,4 -binaphthyl
intermediates are involved in these reactions is that the major
ꢁ
of 1,6-dimethoxynaphthalene at ꢀ78 C followed by a workup with
product (w60%) in the attempted dimerization of 1c, is in fact the
15
0
iodine using the method of Mellin and Hacksell. This was con-
verted to the bromide 1c by reaction with cuprous bromide and to
the para-methoxyphenyl derivative 1e through a Suzuki reaction.
The trimethoxynaphthalene 1e was obtained through a Diel-
seAlder reaction between 4,5-dimethoxybenzyne and furan,
corresponding 4,4 -binaphthyl 3 (Scheme 1). Indeed, we attribute
16
the low yield of 2c via the direct dimerization of 1c to the limited
solubility of the intermediate 3 and, in particular, of its carbocation.
A rather unusual aspect of the dimerization reactions shown in
Scheme 1 is that oxidative couplings of this type usually result in
bond formation ‘ortho’ or ‘para’ to alkoxy or alkylamino sub-
stituents (bond formation at the sites where the spin-density of the
radical cation intermediates is highest) but, in the benzo[j]fluo-
ranthene forming reactions, one of the bonds is formed ‘meta’ to an
alkoxy group. However, if the binaphthyl shown in Scheme 2 is
indeed an intermediate then the ‘meta’ coupling (coupling oem
shown in formula 6) follows naturally because ‘ortho’ coupling
(coupling oeo in formula 6) would lead to a very sterically hindered
product.
17
18,19
acid catalyzed ring opening of the adduct to give 6,7-
dimethoxynaphthol and methylation using methyl iodide/potas-
sium carbonate.
The iodo-derivative 1b did not survive the rather strong ferric
chloride oxidative reaction conditions and neither did the
methoxyphenyl system 1d. However, the methoxy derivative 1e
gave the corresponding ‘dimer’ in reasonably good yield (up to 65%)
and as a single regioisomer, whilst the bromo derivative 1c gave
a more modest yield (w25%).
It seems likely that the regiospecificity of these reactions is
dictated by the fact that the first carbonecarbon bond formed is
Since these reaction conditions were effective in the formation
of fused naphthyl/five-membered ring products; we next
addressed the possibility of using this approach for the synthesis of
fluoranthenes through the cyclization of 1-phenylnaphthalenes.
The target molecule chosen was compound 14 (Scheme 3). This was
chosen because (1) oxidative coupling reactions of this type gen-
erally are best for polyalkoxylated aromatic compounds; (2) in the
intermediate phenylnaphthalene 12 there is a sterically unhindered
2
0
between the 4-positions of two naphthalene molecules: possibly
a 4,4-coupling of a pair of radical cations. In support of this hy-
pothesis we were able to show that the putative intermediate 6 in
the ‘dimerization’ of 1a gives a higher yield of 2a (65%) than that
obtained directly from 1a under identical reaction conditions
(Scheme 2). The 4-iodonaphthalene 4 was made by reacting 1,6-

D.J. Tate et al. / Tetrahedron 70 (2014) 67e74
69
OMe
I
OMe
Pinacol borane/Et
3
N
PdCl (dppf)/Dioxane
2
MeO
MeO
B
4
O
O
5
Pd(PPh
Ba(OH)
Dioxane
3 4
)
2
OMe
OMe
OMe
MeO
MeO
OMe
1. FeCl
3
/DCM
2. MeOH
OMe
OMe
6
2a
Scheme 2. Synthesis of the benzo[j]fluoranthene 2a by oxidative cyclization of the binaphthyl.
‘
ortho/para’ (high spin site to high spin site) coupling; (3) this
The first part of the synthesis shown in Scheme 3 was based on
the route to 2,3,6,7-tetramethoxynaphthalene 9 described by
coupling (oep in formula 12) gives a less sterically hindered
product than the alternative (oeo in formula 12) and so the reaction
should be regiospecific; and (4) it was hoped that the product 14,
like the triphenylene derivative 2,3,6,7,10,11-hexahexyloxytri
2
3
Hellberg et al.
although some modifications were required.
Hence, 2,7-dihydroxynaphthalene was treated with excess bromine
and the polybrominated intermediate(s) reduced back to 3,6-
dibromo-2,7-dihydroxynaphthalene 7 with tin in a simple one-
22
phenylene, would be liquid crystalline.
HO
Br
OH
Br
MeO
Br
OMe
Br
MeO
MeO
OMe
OMe
MeI/K
2
CO
3
NaOMe/CuI
Acetone
9
7
8
1
. HBr/Bu
4
NBr
CO
2
. C 13Br/K
6
H
2
3
/DMF
HxO
HxO
OHx
OHx
HxO
HxO
OHx
OHx
HxO
HxO
OHx
OHx
Pd(PPh
3
)
4
2
Br /DCM
K
2
CO /DME
3
Br
1
1
10
1
2
OHx
OHx
1
. FeCl
3
/DCM
2
3
. MeOH
2 3
. C 13Br/K C) /DMF
6
H
Cl
HxO
HxO
OHx
HxO
HxO
OHx
OHx
Pd(OAc)
OHx KF/H
2
/PHMS
2
O
HxO
OHx
HxO
OHx
1
3
14
Scheme 3. Synthesis of the fluoranthene 14 through oxidative cyclization of the phenylnaphthylene.

70
D.J. Tate et al. / Tetrahedron 70 (2014) 67e74
pot procedure. Alkylation with methyl iodide to give 3,6-dibromo-
,7-dimethoxynaphthalene 8 was straightforward but attempts to
{1H} NMR spectra were recorded on a 300 or 500 MHz spec-
trometer. The progress of reactions was monitored by TLC on pre-
coated silica plates and visualized by ultraviolet light or staining
with vanillin or potassium permanganate. Column chromatogra-
phy employed Merck Kieselgel (60 A) F254 (230e400 mesh) silica
and HPLC grade solvents.
2
prepare 2,3,6,7-tetramethoxynaphthalene from this according to
the procedure of Hellberg et al. using stoichiometric amounts of
sodium methoxide and copper(I)iodide were met with very little
success. However, when excess sodium methoxide was used and
additional copper(I)iodide was added during the reaction, a 70%
yield was obtained. The problem is most likely related to the ease
with which copper(I) catalysts degrade under the reaction condi-
ꢀ
4.2. 7-Iodo-1,6-dimethoxynaphthalene (1b)15
2
4
tions. Conversion to 2,3,6,7-tetrakis(hexyloxy)naphthalene 10
was achieved by dealkylation using HBr/Bu NBr to give the air-
Butyllithium (2.5 M solution in hexanes, 10.1 mL, 26.5 mmol)
ꢁ
4
was added dropwise to a cooled (ꢀ78 C) stirred solution of 1,6-
sensitive tetrahydroxynaphthalene, which was not isolated but
immediately realkylated using hexylbromide/potassium carbonate.
Monobromination and a Suzuki coupling reaction gave the desired
phenylnaphthalene 12 without difficulty. As sometimes happens
with long-chain alkoxy ethers under ferric chloride/methanol
coupling conditions, the oxidative cyclization of 12 was accompa-
nied by a small amount of dealkylation. The ease/extent of deal-
kylation in these ferric chloride mediated couplings usually
increases methoxy<<other primary alkoxy<<secondary alkoxy. In
this case the TLC of the crude product showed several yellow ‘flu-
oranthene spots’ and so the crude reaction mixture was realkylated
dimethoxynaphthalene (5.00 g, 26.5 mmol) in anhydrous THF
(50 mL) under an argon atmosphere. Upon completion of the ad-
dition, the reaction mixture was allowed to warm to room tem-
ꢁ
perature for 12e14 h. The mixture was again cooled (ꢀ78 C) and
iodine (6.74 g, 26.5 mmol) in anhydrous THF (50 mL) was added
dropwise over 1 h. The reaction mixture was brought to room
temperature and quenched with satd NH
Na (15 mL). The mixture was concentrated in vacuo and the
organic dissolved in diethyl ether (200 mL), washed with water
) and concentrated in vacuo to approxi-
4
Cl (10 mL) and satd
2 2 3
S O
(3ꢂ50 mL), dried (MgSO
4
mately 50 mL. The concentrated solution was filtered through
a Celite/silica plug eluting with diethyl ether and the filtrate con-
centrated in vacuo to yield a colourless solid (6.37 g, 76%), which
was recrystallized from MeOH to afford the title compound as off
2
5
using hexylbromide/potassium carbonate, which gave a single
major product (one yellow ‘fluoranthene spot’ in the TLC). However,
this was not the expected product 14 but the monochloro com-
ꢁ
15
ꢁ
1
pound 13 (accurate mass for C52
7
H
81
O
6
Cl and 1H singlets at
.62 and 7.21 in the H NMR spectrum). Although this type of ring
chlorination under ferric chloride/dichloromethane coupling con-
d
7.68,
white prisms, mp 110e112 C (lit. mp 110.5e112 C). H NMR
(300 MHz, CDCl 8.72 (s, 1H), 7.45e7.28 (m, 2H), 7.01 (s, 1H),
1
3
) d
13
6.72e6.54 (d, J¼7.6 Hz, 1H) 3.95 (s, 6H). C NMR (75 MHz, CDCl
3
):
2
6
ditions is very unusual it is not without precedent. The 3-chloro
rather than 7-chloro) structure for compound 13 is somewhat
d
155.6, 154.6, 135.6, 134.0, 127.3, 122.2, 119.0, 105.3, 102.5, 86.8,
ꢀ1
(
56.3, 55.5. IR (ATR) max (cm ) 2959, 2928, 2836, 1576, 1447, 1424,
n
þ
þ
tentatively assigned on the basis of the aromatic chemical shifts
and likely steric hindrance in the case of 7-chloro. Attempts to
confirm the structure by means of 2-D HSQC and HMBC experi-
1385, 1359. HRMS (EI , 70 eV) m/z: [M] calcd for C12
313.9798, found 313.9794. Anal. Calcd for C12 I: C, 45.88; H,
3.53; I, 40.40. Found: C, 46.04; H, 3.26; I, 39.99.
11 2
H O I
11 2
H O
2
ments proved inconclusive. Reduction of 13 to 14 using Pd(OAc) /
PHMS/KF27 gave a 63% yield of the desired product 14. This was
obtained as a low-melting yellow solid (mp. 33 C) and showed no
4.3. 7-Bromo-1,6-dimethoxynaphthalene (1c)
ꢁ
liquid crystal properties.
7-Iodo-1,6-dimethoxynaphthalene (2.00 g, 6.37 mmol) and
copper(I)bromide (1.83 g, 12.7 mmol) were stirred at reflux in an-
hydrous DMF (30 mL) under an atmosphere of argon for 24 h. The
reaction mixture was allowed to cool, diluted with DCM (50 mL)
and washed with 10% HCl (3ꢂ20 mL), water (2ꢂ20 mL), dried
3
. Conclusions
Most interest in benzo[j]fluoranthene and its derivatives arises
because of their carcinogenic activity and the fact that they are so
4
(MgSO ) and concentrated in vacuo. The crude brown solid was
2
8
widely spread in the environment. However, benzofluoranthenes
also have unique electro-optic properties, which are suggestive of
potential applications.29 We have shown that tetraalkoxy benzo[j]
fluoranthenes can be made in a very simple manner by oxidative
dimerization of 1,6-dialkoxynaphthalenes. We propose that the
reaction proceeds through a binaphthyl intermediate followed by
closure of the five-membered ring. In suitable cases, alkoxylated
benzo[j]fluoranthenes can also be made from the corresponding
binaphthyls or fluoranthenes from the corresponding alkoxylated
phenylnaphthalenes.
purified by column chromatography eluting with 20% DCM/hexane
v/v (R z0.35) to yield a colourless powder (1.51 g, 88%), which was
recrystallized from EtOH to afford the title compound as colourless
f
ꢁ
1
plates. Mp 108e110 C. H NMR (300 MHz, CDCl
3
) d 8.47 (s, 1H),
7.39e7.26 (m, 2H), 7.10 (s, 1H), 6.69 (d, J¼6.8 Hz, 1H), 3.99 (s, 3H),
13
3.97 (s, 3H). C NMR (CDCl
3
, 75 MHz) d 154.7, 154.0, 134.7, 127.53,
127.47, 121.3, 118.9, 112.3, 106.4, 102.6, 56.2, 55.5. IR (ATR)
n
max
ꢀ
1
þ
(cm ) 3010, 2931, 2836, 1581, 1448, 1427, 1386. HRMS (ESI ); m/z:
þ
[MþH] calcd for C12
H12BrO
2
267.0015, found 267.0021. Anal. Calcd
Br: C, 53.96; H, 4.15; Br, 29.91. Found: C, 53.70; H, 4.30;
for C12
H
11
O
2
Br, 29.85.
4
4
. Experimental section
4.4. 1,6-Dimethoxy-7-(4-methoxyphenyl)-naphthalene (1d)
.1. General procedures
Barium hydroxide octahydrate (0.60 g, 1.7 mmol) and
Unless otherwise stated, all reagents and solvents were ob-
PdCl
solution of 7-iodo-1,6-dimethoxynaphthalene (0.50 g, 1.6 mmol)
and 2-(4-methoxyphenyl)-4,4,5,5-tetramethyl-[1,3,2]dioxabor-
olane (0.45 g, 1.9 mmol) dissolved in DME/water (60/15 mL) and
degassed with argon for a further 1 h. The mixture was brought to
reflux for 16 h, allowed to cool, diluted with DCM (100 mL), filtered
through a Celite plug. The organics were washed successively with
2
(dppf) (0.06 g, 0.08 mmol) were added to an argon degassed
tained from commercial suppliers and were used without further
purification. Anhydrous THF, diethyl ether, dioxane and toluene
were pre-dried over sodium wire prior to continuous distillation
over sodium-benzophenone (except toluene, which was distilled
over sodium). DCM was pre-dried over calcium chloride and
freshly distilled over calcium hydride. All were distilled under an
atmosphere of oxygen free molecular nitrogen. Other anhydrous
10% HCl (2ꢂ20 mL), water (2ꢂ20 mL), dried (MgSO
4
) and concen-
1
13
solvents were used as supplied (water content <0.05%). H and
C
trated to afford the crude as a brown oil. This was purified by

D.J. Tate et al. / Tetrahedron 70 (2014) 67e74
71
column chromatography eluting with 25% DCM/hexane v/v
z0.35) to afford a colourless powder (0.40 g, 85%), which was
recrystallized from EtOH to afford the title compound as fine col-
4.7. Attempted synthesis of 2b
(R
f
Compound 1b was treated in an identical manner to that of 1a.
After extraction and concentration in vacuo, TLC and NMR spec-
troscopy of the crude product indicated that the desired product
was not present.
ꢁ
1
3
ourless needles. Mp 136.5e137 C. H NMR (300 MHz) CDCl ) d 8.16
(
6
3
1
5
s, 1H), 7.58, (d, J¼8.5 Hz, 2H), 7.36 (d, J¼4.3 Hz, 2H), 7.18 (s, 1H),
.99 (d, J¼8.5 Hz, 2H), 6.72 (t, J¼4.3 Hz,1H), 3.98 (s, 3H), 3.92 (s, 3H),
.86 (s, 3H). 13C NMR (75 MHz, CDCl
158.8, 155.8, 155.7, 135.1,
31.1, 131.0, 130.9, 126.4, 124.1, 120.7, 118.3, 113.5, 105.5, 102.2, 55.51,
3
) d
4.8. 5,10-Dibromo-3,6,8,11-tetramethoxybenzo[j]fluo-
ꢀ
1
0
0
0
0
5.47, 55.3. IR (ATR)
n
max (cm ) 3000, 2960, 2936, 2836, 1493.
ranthene (2c) and 6,6 -dibromo-4,4 ,7,7 -tetramethoxy-1,1 -
binaphthalene (3)
þ
þ
HRMS (EI , 70 eV); m/z: [M] calcd for C19
H
18
O
3
294.1250, found
2
7
94.1246. Anal. Calcd for C19
7.44; H, 6.10.
H
18
O
3
: C, 77.53; H, 6.16. Found: C,
Anhydrous ferric chloride (1.26 g, 7.87 mmol) was added por-
ꢁ
tionwise to a cooled (0 C) stirred solution of 7-bromo-1,6-
4
.5. 1,6,7-Trimethoxynaphthalene (1e)
,7-Dimethoxynaphthol19 (750 mg, 3.68 mmol), potassium
dimethoxynaphthalene (0.30 g, 1.1 mmol) dissolved in anhydrous
DCM (5 mL) under an argon atmosphere. The mixture was allowed
to warm to room temperature and stirring continued for a further
6
ꢁ
carbonate (761 mg, 5.50 mmol) and methyl iodide (343 L,
m
12 h. Upon completion the mixture was cooled (0 C) and quenched
ꢁ
5
0
.50 mmol) dissolved in anhydrous DMF (10 mL) were stirred at
with cold (0 C) methanol (20 mL). The mixture was diluted with
ꢁ
C for 2 h under argon. The reaction mixture was diluted with
DCM (50 mL), washed successively with 10% HCl (2ꢂ25 mL), water
water (10 mL) and extracted with DCM (2ꢂ10 mL), washed with
brine (10 mL), water (10 mL), dried (MgSO ) and concentrated in
vacuo. The resultant crude mixture was purified by column chro-
matography eluting with 30% EtOAc/hexane v/v (R z0.4) to yield
a colourless powder (742 mg, 91%), which was recrystallized from
toluene to afford the title compound as colourless prisms. Mp
(2ꢂ25 mL), dried (MgSO
4
) and concentrated in vacuo. The crude
4
brown solid was purified by column chromatography eluting with
20% EtOAc/hexane v/v (R z0.60) to afford 3 (757 mg, 61%) as
a colourless solid, which was recrystallized from CHCl /EtOH. Mp
8.58 (s, 2H), 7.36 (d, J¼7.9 Hz,
f
f
3
ꢁ
1
>270 C. H NMR (300 MHz, CDCl
2H), 6.83 (d, J¼7.9 Hz, 2H), 6.70 (s, 2H), 4.07 (s, 6H), 3.56 (s, 6H);
NMR (75 MHz, CDCl 154.4, 154.1, 134.1, 129.2, 127.3, 121.4, 112.6,
3
) d
13
C
ꢁ
30
ꢁ
1
133e134 C (lit. mp 132e133 C). H NMR (300 MHz, CDCl
3
)
d
7.53
3
) d
þ
þ
(
4
s, 1H), 7.31e7.23 (m, 2H), 7.01 (s, 1H), 6.73 (dd, J¼7.0, 1.6 Hz, 1H),
105.6, 102.6, 56.0, 55.6; HRMS (EI , 70 eV); m/z [M] calcd for
13
ꢀ1
.02 (s, 3H), 4.00 (s, 6H); C NMR (75 MHz, CDCl
3
)
d
154.9 and
24 20
C H O
4
Br
2
529.9728, found 529.9722. IR (ATR)
n
max (cm ) 2960,
1
50.1, 149.3, 130.7, 124.9, 121.0, 119.3, 106.6, 103.1, 101.3, 56.3, 56.2
2932, 2832, 1612, 1586, 1447, 1427, 1317. Anal. Calcd for
: C, 54.16; H, 3.79; Br, 30.03. Found: C, 54.4; H, 3.75; Br,
29.80. Later fractions (R z0.45) contained compound 2c as a bright
orange solid (312 mg, 25%), which was recrystallized from toluene/
ꢀ1
and 55.9. IR (ATR)
n
max (cm ) 3053, 3010, 2961, 2835, 1586, 1500,
24 2 4
C H20Br O
þ
þ
1456, 1377. HRMS (EI , 70 eV); m/z: [M] calcd for C13
H
14
O
3
f
218.0943, found 218.0953. Anal. Calcd for C13 : C, 71.54; H,
14 3
H O
ꢁ
1
6
.47. Found: C, 71.35; H, 6.56.
EtOH to afford bright orange needles. Mp 242e246 C. H NMR
300 MHz, CDCl
8.55 (s, 1H), 8.39 (s, 1H), 8.03 (d, J¼7.7 Hz, 1H),
7.77 (s, 1H), 7.54 (s, 1H), 6.84 (d, J¼8.1 Hz, 1H), 4.15 (s, 3H), 4.14 (s,
(
3
) d
4
.6. 3,6,8,11-Tetramethoxybenzo[j]fluoranthene (2a)
13
3
3
H), 4.12 (s, 3H), 4.02 (s, 3H); C NMR (CDCl , 75 MHz) d 155.5,
(
a) From the naphthalene. Ferric chloride (5.60 g, 34.5 mmol) was
154.8, 154.5, 152.6, 136.4, 134.3, 130.5, 129.8, 128.4, 128.0, 127.8,
ꢁ
added portionwise to a cooled (0 C) stirred solution of 1,6-
dimethoxynaphthalene (1.00 g, 5.3 mmol) dissolved in anhydrous
DCM (10 mL) under an atmosphere of argon. Upon completion of
the addition the mixture turned deep red/brown in colour and
125.5, 123.9, 121.5, 120.4, 118.5, 112.0, 105.6, 103.2, 100.1, 61.7, 56.2,
þ
55.9, 55.8. HRMS (EI , 70 eV) calcd for C24
527.9562. IR (ATR)
1460, 1414, 1390.
H
18Br
2
O
4
527.9572, found
ꢀ1
n
max (cm ) 2996, 2937, 2833, 1610, 1583, 1483,
stirring was continued for a further 12 h. The reaction was cooled
ꢁ
(
0
C) and quenched with cold methanol (50 mL). The resultant
4.9. Attempted synthesis of 2d
crude was extracted with DCM (100 mL), washed successively with
0% HCl (2ꢂ30 mL), water (2ꢂ30 mL), dried (MgSO ) and concen-
trated in vacuo. The crude was purified by column chromatography,
1
4
Compound 1d was treated in an identical manner to that of 1a.
After extraction and concentration in vacuo, TLC and NMR of the
crude product indicated that the desired product was not present.
eluting with DCM (R
f
z0.30) to afford a yellow powder (0.44 g,
ꢁ
4
5%), which was recrystallized from DCM/EtOH. Mp 239 C. (b)
From the binaphthyl. Ferric chloride (0.97 g, 6.01 mmol) was added
portionwise to a stirred solution of 4,7,4 ,7 -tetramethoxy-[1,1 ]
binaphthalenyl (0.75 g, 2.00 mmol) dissolved in anhydrous DCM
4.10. 3,5,6,8,10,11-Hexamethoxybenzo[j]fluoranthene (2e)
0
0
0
Anhydrous ferric chloride (1.06 g, 6.41 mmol) was added por-
tionwise to a stirred solution of 1,6,7-trimethoxynaphthalene (1e,
0.20 g, 0.92 mmol) dissolved in anhydrous DCM (5 mL) under ar-
gon. Upon completion of the addition the mixture turned deep red
in colour and was stirred overnight at room temperature. The re-
(
10 mL) under an argon atmosphere. Upon completion of the ad-
dition the mixture turned deep red in colour and stirring was
continued for 12 h. The reaction was cooled and quenched with
cold methanol (30 mL). Workup as before gave a yellow powder
ꢁ
(
2
8
7
1
d
0.47 g, 65%), which was recrystallized from DCM/EtOH. Mp
action mixture was cooled (0 C, ice bath) and quenched with cold
ꢁ
1
39e242 C. H NMR (300 MHz CDCl
3
)
d
8.24 (d, J¼9.2 Hz, 1H),
methanol (10 mL). The resultant mixture was extracted with DCM
.15e8.11 (2ꢂd, J¼9.2, 7.7 Hz, 2H), 7.86 (d, J¼2.1 Hz,1H), 7.62 (s,1H),
(2ꢂ20 mL), washed with 10% HCl (2ꢂ5 mL), dried (MgSO
concentrated in vacuo. The product was purified by chromatogra-
phy on silica gel eluting with DCM (R z0.30) to afford a yellow/
orange powder (0.13 g, 65%), which was recrystallized from CHCl
EtOH to afford the title compound as yellow prisms. Mp
4
) and
.28 (d, J¼9.2 Hz, 1H), 7.09 (dd, J¼9.2, 2.1 Hz, 1H), 6.79 (d, J¼7.7 Hz,
13
H), 4.18 (s, 3H), 4.13 (s, 3H), 4.04 (s, 6H); C NMR (75 MHz, CDCl
158.8, 156.0, 155.9, 155.2, 137.6, 134.9, 131.8, 130.0, 125.1, 125.0,
23.8, 120.8, 117.7, 115.7, 113.4, 103.9, 103.3, 100.3, 56.0, 55.8, 55.3.
3
)
f
3
/
1
þ
þ
ꢁ
1
HRMS (ESI ); m/z: [MþH] calcd for C24
H
21
O
4
373.1434, found
max (cm ) 2991, 2936, 2838, 1614, 1587, 1480,
454. Anal. Calcd for C24 : C, 77.42; H, 5.41. Found: C, 77.25; H,
.75.
231e232 C. H NMR (300 MHz, CDCl
3
)
d
7.94 (d, J¼7.8 Hz, 1H), 7.80
ꢀ
1
3
1
5
73.1424. IR (ATR)
n
(s, 1H), 7.62 (s, 1H), 7.61 (s, 1H), 7.43 (s, 1H), 6.83 (d, J¼7.8 Hz, 1H),
13
20
H O
4
4.14e4.06 (6ꢂs, 18H); C NMR (75 MHz, CDCl 155.4, 154.6,
3
) d
154.3,150.7,148.8,147.8, 134.9,130.4,127.6, 126.8,126.5,121.3, 121.1,

72
D.J. Tate et al. / Tetrahedron 70 (2014) 67e74
1
19.4, 105.5, 103.6, 102.6, 102.4, 100.9, 61.6, 56.6, 56.2, 56.2, 56.1; IR
J¼9.2 Hz, 2H), 7.35 (d, J¼7.8 Hz, 2H), 7.10 (dd, J¼9.2, 2.5 Hz, 2H), 6.75
13
ꢀ1
(
(
ATR)
n
max (cm ) 3011, 2937, 2888, 2830, 1592, 1426, 1357. HRMS
(d, J¼7.9 Hz, 2H), 6.72 (d, J¼2.5 Hz, 2H), 4.05 (s, 6H), 3.53 (s, 6H).
C
þ
þ
EI , 70 eV); m/z: [M] calcd for C26
24
H O
6
432.1573, found
NMR (75 MHz, CDCl 158.4, 155.5, 135.7, 130.3, 129.2, 124.2, 121.1,
3
) d
ꢀ
1
4
32.1570.
117.5, 105.7, 102.1, 55.9, 55.51. IR (ATR)
831, 1615, 1585, 1450, 1426. HRMS (EI , 70 eV); m/z: [M] calcd for
n
max (cm ) 3008, 2937,
þ
þ
2
4
.11. 4-Iodo-1,6-dimethoxynaphthalene (4)
24 22 4
C H O 374.1513, found 374.1517.
N-Iodosuccinimide (5.57 g, 29.2 mmol) was added portionwise
stirred solution of 1,6-dimethoxynaphthalene (5.00 g,
4.14. 3,6-Dibromo-2,7-dihydroxynaphthalene (7)
to
a
2
6.5 mmol) and trifluoroacetic acid (0.62 mL, cat. amount) dis-
Bromine (26.0 g, 0.162 mol) dissolved in acetic acid (50 mL) was
added dropwise over a 20 min period to a stirred solution of 2,7-
dihydroxynaphthalene (6.5 g, 0.046 mol) dissolved in acetic acid
150 mL). The mixture was diluted with water (20 mL) and brought
to reflux. Upon discolouration of bromine, powdered tin (10 g,
.084 mol) was added portionwise. The mixture was allowed to
solved in acetonitrile (125 mL). Upon completion of the addition
the mixture turned dark brown. Stirring was continued for 2 h.
Volatile organics were removed in vacuo and the resultant crude oil
extracted with diethyl ether (100 mL). The organics were washed
(
successively with satd NaHCO
3
(2ꢂ50 mL), water (2ꢂ50 mL), dried
0
(
(
MgSO
6.50 g, 78%), which was recrystallized from EtOH. Mp 64 C. H
8.15 (d, J¼9.2 Hz, 1H), 7.90 (d, J¼8.2 Hz,
H), 7.32 (d, J¼2.5 Hz, 1H), 7.12 (dd, J¼9.2, 2.5 Hz, 1H), 6.47 (d,
4
) and concentrated in vacuo to afford a pale brown solid
reflux for a further 4 h, allowed to cool to room temperature and
diluted with water (100 mL), the precipitated product was filtered
as a colourless solid (10.50 g, 72%), which was recrystallized from
ꢁ
1
3
NMR (300 MHz, CDCl ) d
1
ꢁ
30
ꢁ
1
AcOH. Mp 188e190 C (lit. mp 186e190 C). H NMR (300 MHz,
13
J¼8.2 Hz, 1H). 3.97 (s, 3H), 3.95 (s, 3H); C NMR (75 MHz, CDCl
3
)
13
DMSO-d
6
)
d
10.50 (s, 2H), 8.01 (s, 2H), 7.06 (s, 2H); C NMR
75 MHz, DMSO-d 152.5, 134.3, 131.0, 124.4, 110.1, 108.4. IR (ATR)
max (cm ) 3500e3300 (b), 2866, 2745, 1615, 1588, 1525. HRMS
d
158.4, 155.5, 135.7, 130.3, 129.2, 124.2, 121.1, 117.5, 105.7, 102.12,
(
n
6
) d
ꢀ1
5
5.91, 55.90. IR (ATR)
n
max (cm ) 2925, 2897, 2858, 1588, 1430,
ꢀ1
þ
þ
1353. HRMS (EI , 70 eV); m/z: [M] calcd for C12
H11IO
2
313.9798,
þ
þ
(
3
6 2 2
EI , 70 eV); m/z: [M] calcd for C10H Br O 315.8735, found
found 313.9796. Anal. Calcd for C12
Found: C, 46.00; H, 3.50; I, 40.30.
H11IO
2
: C, 45.88; H, 3.53; I, 40.40.
15.8741.
4.15. 3,6-Dibromo-2,7-dimethoxynaphthalene (8)
4
.12. 2-(4,7-Dimethoxynaphthalen-1-yl)-4,4,5,5-tetramethyl-
[1,3,2]dioxaborolane (5)
A solution of 3,6-dibromo-2,7-dihydroxynaphthalene (7, 3.00 g,
9
.43 mmol), potassium carbonate (3.91 g, 28.3 mmol) and methyl
4
-Iodo-1,6-dimethoxynaphthalene (3, 5.00 g, 15.9 mmol),
pinacol borane (3.10 g, 23.8 mmol) and triethylamine (6.66 mL,
7.7 mmol) were dissolved in anhydrous dioxane (100 mL) and
subsequently degassed with argon for 1 h. PdCl (dppf) (0.40 g,
.7 mmol) was added to the mixture and degassed for a further
.5 h. The mixture was brought to reflux with stirring for 3 h,
iodide (1.71 mL, 28.3 mmol) dissolved in anhydrous acetone
100 mL) were stirred at room temperature under argon for 4 h. The
(
4
reaction mixture was filtered through a Celite pad to remove the
inorganics, which was washed with DCM (100 mL). The combined
organic filtrate and washings were washed with 10% HCl
2
4
0
(
2ꢂ50 mL), water (2ꢂ50 mL), dried (MgSO
4
) and concentrated in
allowed to cool and extracted with diethyl ether (100 mL). The
) and
vacuo. The crude solid was recrystallized from ethanol to afford the
organics were washed with water (2ꢂ50 mL), dried (MgSO
4
ꢁ
title compound as fine white needles (2.50 g, 77%), mp 177e178 C
concentrated in vacuo. The resultant crude oil was purified by
chromatography on silica gel eluting with 50% DCM/hexane v/v to
afford 5 as a pale orange oil (4.20 g, 84%), which crystallized on
3
0
ꢁ
1
(lit. mp 176.5e178 C). H NMR (300 MHz, CDCl
3
)
d
7.88 (s, 2H),
154.3, 133.9,
1
3
7.05 (s, 2H), 3.98 (s, 6H); C NMR (75 MHz, CDCl
3
)
d
ꢀ
1
ꢁ
1
131.0, 125.3, 111.4, 105.7, 56.2; IR (ATR) max (cm ) 2994, 2940,
n
standing over a period of a few days. Mp 89e90 C. H NMR
300 MHz, CDCl
þ
þ
2
869, 2858, 1618, 1588, 1491, 1464. HRMS (EI , 70 eV); m/z: [M]
calcd for C12 343.9048, found 343.9059. Anal. Calcd for
: C, 41.65; H, 2.91; Br, 46.18. Found: C, 41.55; H, 2.85; Br,
(
(
3
3
)
d
8.29e8.22 (m, 2H), 8.05 (d, J¼7.8 Hz, 1H), 7.17
2 2
H10Br O
dd, J¼9.2, 2.5 Hz, 1H), 6.74 (d, J¼7.8 Hz, 1H), 4.04 (s, 3H), 4.00 (s,
H), 1.46 (s, 12H); 1 C NMR (75 MHz, CDCl
3
C
12 2 2
H10Br O
6.05.
3
) d 158.8, 140.3, 138.0,
4
1
5
29.2, 123.9, 121.1, 120.8, 117.4, 117.1, 107.6, 105.7, 102.0, 101.6, 83.71,
5.8, 55.4, 25.44. IR (ATR)
HRMS (EI , 70 eV); m/z: [M] calcd for C18
ꢀ1
n
max (cm ) 3005, 2975, 288, 1621, 1581.
þ
þ
H23BO
4
314.1689, found
4.16. 2,3,6,7-Tetramethoxynaphthalene (9)
314.1680. Anal. Calcd for C18
H
23BO : C, 68.81; H, 7.38. Found: C,
4
6
8.55; H, 7.35.
Sodium (0.21 g, 8.6 mmol) was added portionwise to anhydrous
methanol (30 mL) stirred under an argon atmosphere. Upon com-
plete dissolution, copper(I) iodide (1.65 g, 8.64 mmol), 3,6-
dibromo-2,7-dimethoxynaphthalene (7, 1.50 g, 4.32 mmol) and
anhydrous DMF (5 mL), were added to the reaction mixture and
brought to reflux for 24 h. Additional copper(I) iodide (0.83 g,
4.32 mmol) and satd sodium methoxide (20 mL) were added to
regenerate the catalyst and stirred at reflux for an additional 12 h.
The reaction was quenched by the addition of water (10 mL) and
extracted with DCM (2ꢂ25 mL), washed successively with 10% HCl
0
0
0
4
.13. 4,7,4 ,7 -Tetramethoxy-[1,1 ]binaphthalenyl (6)
A stirred solution of 4-iodo-1,6-dimethoxynaphthalene (1.56 g,
5
.0
mmol),
2-(4,7-dimethoxy-naphthalen-1-yl)-4,4,5,5-
tetramethyl-[1,3,2]dioxaborolane (1.72 g, 5.50 mmol) and barium
hydroxide octahydrate (1.57 g, 5.50 mmol) dissolved in anhydrous
dioxane (100 mL) was degassed with argon for 1 h. Tetrakis-
triphenylphosphine (0.17 g, 0.15 mmol) was added under a fast
stream of argon. The mixture was degassed for a further 0.5 h and
brought to reflux for 16 h. The mixture was allowed to cool,
extracted with chloroform (100 mL). The organic extracts were
washed successively with water (2ꢂ30 mL), dried (MgSO
concentrated in vacuo. The resultant crude was purified by column
chromatography, eluting with 30% DCM/hexane v/v (R z0.40) to
afford a colourless powder (1.65 g, 89%), which was recrystallized
(2ꢂ10 mL), water (2ꢂ10 mL), dried (MgSO
4
) and concentrated in
vacuo to afford a crude solid, which was recrystallized from ethanol
ꢁ
23
to afford the title compound (0.75 g, 70%). Mp 255e256 C (lit.
ꢁ
1
4
) and
mp>200 C). H NMR (300 MHz, CDCl
3
)
d
7.04 (s, 4H), 3.98 (s,
13
12H); C NMR (75 MHz, CDCl
3
)
d
148.1, 124.1, 55.8; IR (ATR)
n
max
ꢀ
1
f
(cm ) 3064, 3003, 2964, 2937, 2887, 1669, 1608, 1528, 1510. HRMS
(EI , 70 eV); m/z: [M] calcd for C14H O 248.1049, found
16 4
þ
þ
ꢁ
1
from EtOH. Mp 198e200 C. H NMR (300 MHz, CDCl
3
)
d
8.52 (d,
248.1048.

D.J. Tate et al. / Tetrahedron 70 (2014) 67e74
73
4
.17. 2,3,6,7-Tetrakis(hexyloxy)naphthalene (10)
,3,6,7-Tetrahydroxynaphthalene was prepared freshly as re-
30% DCM/hexane v/v to afford 12 as a colourless solid (300 mg,
ꢁ
1
91%), which was recrystallized from EtOH. Mp 53e54 C. H NMR
2
(300 MHz, CDCl 7.03 (s, 2H), 6.98e6.93 (m, 2H), 6.90e6.87 (m,
3
) d
quired. A mixture of HBr (20 mL, 48%), tetrabutylammonium bro-
mide (40 mg, 0.12 mmol) and zinc (ca. 200 mg) was brought to
reflux (z130 C). 2,3,6,7-Tetramethoxynaphthalene (2.0 g,
2H), 4.10e4.04 (m, 4H), 3.96e3.92 (m, 2H), 3.84e3.81 (m, 2H),
3.79e3.66 (m, 4H), 1.89e1.68 (m, 12H), 1.54e1.28 (m, 36H),
ꢁ
13
0.92e0.80 (m, 18H); C NMR (75 MHz, CDCl
3
)
d
150.6, 148.9, 148.6,
8
.1 mmol) was added in a single portion and stirred at reflux for 1 h.
The reaction mixture was allowed to cool and diluted with water
20 mL) and filtered. The filtrate was concentrated in vacuo and re-
suspended in water (20 mL). The suspension was filtered, washed
with water and dried over P . The product was used in the next
step without further purification. 2,3,6,7-Tetrahydroxynaphthalene
1.00 g, 5.20 mmol), potassium carbonate (5.74 g, 41.6 mmol),
148.0, 147.7, 129.2, 126.7, 123.2, 116.6, 113.3, 107.6, 106.5, 73.5, 69.3,
69.2, 69.0, 68.9, 68.3, 31.7, 31.6, 30.1, 29.4, 29.3, 29.1, 29.0, 25.9,
ꢀ
1
(
25.82, 25.7, 25.5, 22.6, 14.0, 14.0. IR (ATR)
n
max (cm ) 2953, 2928,
þ
þ
2857, 1503, 1466, 1414. HRMS (EI , 70 eV); m/z: [M] calcd for
2
O
5
C
52
H
84
O
6
804.6268, found 804.6265. Anal. Calcd for C52
84 6
H O : C,
77.56; H, 10.51. Found: C, 77.42, H, 10.22.
(
hexylbromide (6.96 g, 41.6 mmol) and potassium iodide (a few
4.20. 3-Chloro-1,2,5,6,8,9-hexakis(hexyloxy)fluoranthene (13)
small crystals) dissolved in anhydrous DMF (20 mL) were stirred at
ꢁ
6
5
C for 24 h under an argon atmosphere. The reaction was
Anhydrous ferric chloride (120 mg, 0.18 mmol) was added
0
0
allowed to cool and was diluted with water, extracted with DCM
2ꢂ30 mL). The combined organic extracts were washed with
) and concentrated in vacuo. The
portionwise to a stirred solution of 1-(3 ,4 -bis(hexyloxy)phenyl)-
2,3,6,7-tetrakis(hexyloxy)naphthalene (12, 150 mg, 0.75 mmol)
dissolved in anhydrous DCM (5 mL) under an argon atmosphere.
Upon completion of the addition the reaction mixture turned
deep red in colour and was stirred overnight. The reaction mix-
(
water (2ꢂ20 mL), dried (MgSO
4
resultant crude product was chromatographed on silica gel eluting
with 20% DCM/hexane v/v to afford a colourless solid (1.98 g, 72%),
ꢁ
1
ꢁ
which was recrystallized from EtOH. Mp 118e119 C. H NMR
300 MHz, CDCl
7.00 (s, 4H), 4.06 (t, J¼6.6 Hz, 8H), 1.90e1.82 (m,
H), 1.54e1.43 (m, 8H), 1.36e1.24 (m, 16H), 0.92 (t, J¼6.7 Hz, 12H);
ture was cooled (0 C, ice bath) and quenched with methanol
(
3
)
d
(5 mL). The mixture was diluted with DCM (20 mL), washed with
8
10% HCl (2ꢂ10 mL), dried (MgSO
4
) and concentrated in vacuo. The
1
3
C NMR (75 MHz, CDCl
2.6, 14.0; IR (ATR)
3
)
d
148.1, 124.4, 107.8, 69.0, 31.6, 29.2, 25.7,
crude product was subsequently realkylated with an excess of
ꢀ1
ꢁ
2
1
n
max (cm ) 2950, 2932, 2871, 2855, 1605, 1508,
hexylbromide, potassium carbonate in DMF for 24 h at 65 C.
þ
þ
418. HRMS (EI , 70 eV); m/z: [M] calcd for C34
H
56
O
4
528.4179,
Upon completion of the reaction, the organics were extracted in
found 528.4189. Anal. Calcd for C34
C, 77.10; H, 10.80.
H
56
O
4
: C, 77.22; H, 10.67. Found:
DCM (2ꢂ30 mL), washed successively with 10% HCl (2ꢂ20 mL),
water (2ꢂ20 mL), dried (MgSO
4
) and concentrated in vacuo. The
crude was purified by chromatography on silica gel eluting with
4
.18. 1-Bromo-2,3,6,7-tetrakis(hexyloxy)naphthalene (11)
40% DCM/hexane v/v to afford a yellow a waxy solid (104 mg,
6
7%), which was recrystallized from Me
2
CO to afford the title
ꢁ
1
Bromine (453 mg, 146
m
L, 2.85 mmol), was added dropwise to
compound a fine yellow needles. Mp 42 C. H NMR (300 MHz,
ꢁ
a cooled (0 C, ice bath) stirred solution of 2,3,6,7-tetra(hexyloxy)
naphthalene (10, 1.50 g, 2.85 mmol) dissolved in DCM (30 mL). The
reaction mixture was allowed to warm to room temperature and
stirred for a further 30 min. The mixture was diluted with DCM
CDCl
3
) d 7.68 (s, 1H), 7.62 (s, 1H), 7.21 (s, 1H), 4.25e4.23 (m, 4H),
4.18e4.07 (m, 8H), 1.96e1.85 (m, 12H), 1.62e1.48 (m, 12H),
ꢀ
1
1.43e1.32 (m, 24H), 0.95e0.89 (m, 18H); IR (ATR)
n
max (cm
)
þ
2950, 2928, 2857, 1604, 1571, 1487, 1463. HRMS (EI , 70 eV); m/z:
þ
(
70 mL), washed with satd Na
2
S
2
O
3
$5H
2
O (2ꢂ20 mL), water
[M] calcd for C52
H81ClO
6
836.5722, found 836.5698. Anal. Calcd
(
2ꢂ30 mL), dried (MgSO ) and concentrated in vacuo. The crude
4
for C52
Cl, 4.45.
H81ClO : C, 74.56; H, 9.75; Cl, 4.23. Found: C, 74.40; H, 9.60;
6
product was purified by chromatography on silica gel eluting with
2
3
2
0% DCM/hexane v/v to afford 11 as a colourless precipitate (0.52 g,
ꢁ
1
0%), mp 65e66 C. H NMR (300 MHz, CDCl
3
)
d
7.43 (s, 1H), 6.99 (s,
4.21. 1,2,5,6,8,9-Hexakis(hexyloxy)fluoranthene (14)
solution of 3-chloro-1,2,5,6,8,9-hexakis(hexyloxy)fluo-
ranthene (13, 75 mg, 0.09 mmol) dissolved in anhydrous THF
(5 mL) was degassed with argon for 0.5 h. Potassium fluoride
(10 mg, 0.18 mmol) dissolved in water (1 mL) was added and the
H), 4.15e4.02 (m, 8H), 1.94e1.82 (m, 8H), 1.55e1.45 (m, 8H),
13
1
d
.37e1.30 (m, 16H), 0.95e0.89 (m, 12H); C NMR (75 MHz, CDCl
151.0, 149.7, 149.3, 145.5, 127.0, 123.6, 115.5, 108.3, 107.9, 107.6,
3.9, 69.46, 69.44, 69.23, 32.1, 32.0, 31.9, 30.6, 29.6, 29.4, 26.2, 26.1,
3
)
A
7
2
ꢀ
þ
1
6.1, 23.0, 23.0, 14.4, 14.0. IR (ATR)
n
max (cm ); 2953, 2928, 2857,
þ
1503,1466, 1414. HRMS (EI , 70 eV); m/z: [M] calcd for C34
H55BrO
4
mixture degassed for a further 0.5 h. Pd(OAc)
0.001 mmol) was added under a fast stream of argon. PMHS (63 m
2
(ca. 2 mg,
L,
6
06.3284, found 606.3289. Anal. Calcd for C34
H55BrO
4
: C, 67.20; H,
9
.12; Br, 13.15. Found: C, 67.10; H, 9.20; Br, 13.15.
0.38 mmol) was added and the mixture stirred at room tempera-
ture for 12 h. Upon completion of the reaction, unreacted PHMS
was hydrolyzed with 3 M NaOH aq (5 mL). The reaction mixture
was diluted with DCM (10 mL), washed with water (2ꢂ5 mL), dried
0
0
4
.19. 1-(3 ,4 -Bis(hexyloxy)phenyl)-2,3,6,7-tetrakis(hexyloxy)
naphthalene (12)
(
4
MgSO ) and concentrated in vacuo. The crude product was puri-
Tetrakistriphenylphosphine (23 mg, 0.02 mmol) was added to
a degassed mixture of ethylene glycol dimethyl ether (30 mL) and
fied by preparative TLC on silica eluting with 40% DCM/hexane v/v
(R z0.6) to afford 14 as a bright yellow powder (50 mg, 68%),
which was recrystallized from (Me
(300 MHz, CDCl
7.69 (s, 2H), 6.98 (s, 2H), 4.22 (t, J¼6.6 Hz, 4H),
4.14e4.07 (m, 8H), 1.93e1.83 (m, 12H), 1.57e1.50 (m, 12H),
f
ꢁ
1
2
M potassium carbonate (0.62 mL, 1.23 mmol) with stirring under
2
CO). Mp 33 C. H NMR
an argon atmosphere. The reaction mixture was degassed for
a further 0.5 h. 1-Bromo-2,3,6,7-tetrakis(hexyloxy)naphthalene (11,
3
) d
13
2
50 mg, 0.41 mmol) and 2-(3,4-bis(hexyloxy)phenyl)-4,4,5,5-
1.39e1.25 (m, 24H), 0.95e0.88 (m, 18H); C NMR (75 MHz, CDCl
3
)
tetramethyl-1,3,2-dioxaborolane (332 mg, 0.83 mmol) were
added under a fast stream of argon. The reaction mixture was
stirred at 70 C for 24 h. The reaction mixture was allowed to cool to
d
153.9, 148.9, 144.6, 131.5, 110.5, 106.3, 74.5, 74.0, 69.7, 69.3, 31.84,
31.77, 31.65, 31.60, 30.8, 30.2, 29.4, 26.0, 25.9, 25.8, 22.6, 14.0; IR
(ATR)
ꢁ
ꢀ1
n
max (cm ) 2951, 2827, 2852, 1601, 1578, 1481, 1465. HRMS
þ
þ
room temperature, diluted with DCM (30 mL), washed with water
(ESI ); m/z: [MþNa] calcd for C52
H
82
O
6
Na 825.6004, found
(
2ꢂ25 mL), dried (MgSO
4
) and concentrated in vacuo. The crude
825.6015. Anal. Calcd for C52
77.70; H, 10.25.
82 6
H O : C, 77.76; H, 10.29. Found: C,
product was purified by chromatography on silica gel eluting with

7
4
D.J. Tate et al. / Tetrahedron 70 (2014) 67e74
4. Boden, N.; Bushby, R. J.; Lu, Z.; Headdock, G. Tetrahedron Lett. 2001, 41, 10117.
4
.22. X-ray crystal structure of 3,6,8,11-tetramethoxybenzo[j]
5
. (a) Boden, N.; Borner, R. C.; Bushby, R. J.; Cammidge, A. N.; Jesudason, M. V. Liq.
Cryst. 1993, 15, 851; (b) Krebs, F. C.; Schiodt, N. C.; Batsberg, W.; Bechgaard, K.
Synthesis 1997, 1285.
fluoranthene (2a)
Single crystals of compound 2a were grown from CHCl
X-ray diffraction measurements were carried out at 150 K on
a Nonius KappaCCD diffractometer using graphite monochromated
3
/EtOH.
6. (a) Boden, N.; Bushby, R. J.; Cammidge, A. N. J. Chem. Soc., Chem. Commun. 1994,
4
9
65; (b) Boden, N.; Bushby, R. J.; Cammidge, A. N. J. Am. Chem. Soc. 1995, 117,
24; (c) Boden, N.; Bushby, R. J.; Lu, Z. Liq. Cryst. 1998, 25, 47.
7. (a) Herbert, R. B.; Kattah, A. E.; Murtagh, A. J.; Sheldrake, P. W. Tetrahedron Lett.
Mo K
a
radiation. The structure was solved by direct methods with
1995, 36, 5649; (b) Yatabe, T.; Harbison, M. A.; Brand, J. D.; Wagner, M.; Mullen, K.;
Samori, P.; Rabe, J. P. J. Mater. Chem. 2000, 10, 1519; (c) Boden, N.; Bushby, R. J.;
Headdock, G.; Lozman, O. R.; Wood, A. Liq. Cryst. 2001, 28, 139; (d) Lee, M.; Kim, J.-
W.; Peleshanko, S.; Larsen, K.; Yoo, Y.-S.; Vaknin, D.; Markutsya, S.; Tsukruk, V. V. J.
Am. Chem. Soc. 2002, 124, 9121.
. (a) Kumar, S.; Varshney, S. K. Liq. Cryst. 1999, 26, 1841; (b) Kumar, S.; Varshney,
S. K. Synthesis 2001, 305.
. Kumar, S.; Manickam, M. Chem. Commun. 1997, 1615.
10. Cooke, G.; Sage, V.; Richomme, T. Synth. Commun. 1999, 29, 1767.
11. Kumar, S.; Lakshmi, B. Tetrahedron Lett. 2005, 46, 2603.
2. Bushby, R. J.; Lu, Z. Synthesis 2001, 763.
3. (a) Older Methods of Synthesis of Benzo[j]fluoranthene are Summarized in Clar
E. J.; Polycyclic Hydrocarbons; Academic: London, 1964, Vol. 2; (b) Dobbs, T. K.;
Hertzler, D. V.; Keen, G. W.; Eisenbraun, E. J. J. Org. Chem. 1980, 45, 4769; (c)
Rice, J. E.; Cai, Z.-W. J. Org. Chem. 1993, 58, 1415.
4. (a) Yax, E.; Ourisson, G. Bull. Soc. Chim. Fr. 1967, 4153; (b) Crawford, M.;
Supanekar, V. R. J. Chem. Soc. 1964, 2380; (c) Crawford, M.; Supanekar, V. R. J.
Chem. Soc. C 1970, 1832; (d) Sharma, K. S.; Taneja, K. L.; Mukherji, S. M. Ind. J.
Chem. 1982, 21B, 572; (e) Rice, J. E.; Shih, H.-C.; Hussain, N.; LaVoie, E. J. J. Org.
Chem. 1987, 52, 849; (f) He, Z.-M.; Rice, J. E.; LaVoie, E. J. J. Org. Chem. 1992, 57,
31
1
ShelXS in the monoclinic space group P2 /n and was refined using
SHELXL-97.32 The asymmetric unit contains one molecule of 2a and
one molecule of chloroform, which was disordered over two po-
sitions with the ratio of the site occupation factors ultimately fixed
at 0.70:0.30. All non-hydrogen atoms were refined anisotropically.
All hydrogen atoms were placed in calculated positions and refined
8
9
ꢀ
using a riding model. CeH distances: methyl, 0.98 A; aromatic,
1
1
ꢀ
0
.95A. All Uiso(H) values were constrained to be 1.2 times (1.5 for
methyl) Ueq of the parent atom. At the conclusion of the re-
finement, the most extreme deviations in the residual electron
ꢀ
density map are 1.40 at 0.6789, ꢀ0.0043, 0.1411 (0.91 A from CL3S)
1
ꢀ
and ꢀ1.43 at 0.7916, 0.0947, 0.1780 (0.80 A from CL3S).
Crystal Data for compound 2a (M¼491.77): monoclinic, space
ꢀ
ꢀ
group P2
c¼24.3735(4) A,
(Mo K
)¼0.442 mm , Dcalcd¼1.466 g/mm , 22,614 reflections
1
/n (no. 14), a¼7.5360(1) A, b¼12.1427(2) A,
ꢀ ꢀ
ꢁ
3
b
¼92.608(1) , V¼2228.05(6) A , Z¼4, T¼150(2) K,
1 3
1
784; (g) Panda, K.; Vankatesh, C.; Ila, H.; Junjappa, H. Eur. J. Org. Chem. 2005,
2045.
5. Mellin, C.; Hacksell, U. Tetrahedron 1987, 43, 5443.
6. Couture, C.; Paine, A. J. Can. J. Chem. 1985, 63, 111.
ꢀ
m
a
1
1
1
measured (6.04ꢃ2 ꢃ52), 4355 unique (Rint¼0.0740), which were
Q
used in all calculations. The final R1 was 0.0571 (>2s(I)) and wR2
7. (a) Miyaura, M.; Ishiyama, T.; Ishikawa, M.; Suzuki, A. Tetrahedron Lett. 1986, 27,
was 0.1499 (all data). CCDC number 967582.
6369; (b) Schilling, B.; Kaufmann, D. E. Eur. J. Org. Chem. 1998, 4, 701.
1
1
8. Lautens, M.; Fagnou, K.; Yang, D. J. Am. Chem. Soc. 2003, 125, 14884.
9. Giles, R. G. F.; Hughes, A. B.; Sargent, M. V. J. Chem. Soc., Perkin Trans. 1 1991,
581.
0. Yang, H. J.; Wipf, D. O.; Bard, A. J. J. Electroanal. Chem. 1992, 331, 913.
1. Carreno, M. C.; Garcia Ruano, J. L.; Saz, G.; Toledo, M. A.; Urbano, A. Tetrahedron
Acknowledgements
1
2
2
D.J.T. acknowledges the support of Merck and the EPSRC for
funding. We also thank Simon Barrett and Robert P.W. Davies for
assistance with NMR files.
Lett. 1996, 37, 4081.
2
2. (a) Bushby, R. J.; Cammidge, A. N. In Handbook of Liquid Crystals; Demus, D.,
Goodby, J. W., Gray, G. W., Spiess, H. W., Vill, V., Eds.; Wiley-VCH: Weinheim,
1998; Vol. 2B, pp 693e748; (b) Kumar, S. Liq. Cryst. 2004, 31, 1037.
2
2
2
3. Hellberg, J.; Dahlstedt, E.; Pelcman, M. E. Tetrahedron 2004, 60, 8899.
4. Keegstra, M. A.; Peters, T. H. A.; Brandsma, L. Tetrahedron 1992, 48, 3633.
5. Bushby, R. J.; Boden, N.; Kilner, C. A.; Lozman, O. R.; Lu, Z.; Liu, Q.; Thornton-Pett,
M. A. J. Mater. Chem. 2003, 13, 470 Details given in the Supplementary data.
Supplementary data
Crystallographic characterization for 2a (CIF). H NMR and 13C
H} spectra for compounds 1be14. Supplementary data related to
1
{1
26. Cammidge, A. N.; Gopee, H. J. Mater. Chem. 2001, 11, 2773.
27. Rahaim, R. J.; Maleczka, R. E. Tetrahedron Lett. 2002, 43, 8823.
this article can be found at http://dx.doi.org/10.1016/
j.tet.2013.11.029.
2
8. (a) Rice, J. E.; Wheland, E. H.; Geddie, N. G.; DeFloria, M. C.; LaVoie, E. J. Cancer Res.
1987, 47, 6166; (b) LaVoie, E. J.; He, Z.-M.; Wu, Y.; Meschter, C. L.; Weyland, E. H.
Cancer Res. 1994, 54, 962; (c) Hecht, S. S.; Riverson, A.; Amin, S.; Krzeminski, J.; El-
Bayoumy, K.; Reddy, B. S.; Kurtzke, C.; LaVoie, E. J. Cancer Lett. 1996, 106, 251.
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2
2
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3