Synthesis and solid state structures of N,N′-linked carbazoles and indoles

Article abstract of DOI:10.1016/S0040-4020(02)00344-7

The synthesis and solid state conformations of a number of N,N′-linked carbazoles and indoles has been investigated. Using xylyl-based linkers, the o, m and p-linked carbazoles and indoles 4-6, 8-10 and 12, 13 were prepared. Likewise, unsymmetrical deriva

Full text of DOI:10.1016/S0040-4020(02)00344-7

TETRAHEDRON
Pergamon
Tetrahedron 58 32002) 3709±3720
Synthesis and solid state structures of N,N0-linked carbazoles
and indoles
Jason Bloxham,a Christopher J. Moodya,b,p and Alexandra M. Z. Slawina,c,²
aDepartment of Chemistry, Loughborough University, Loughborough, Leicestershire LE11 3TU, UK
bSchool of Chemistry, University of Exeter, Stocker Road, Exeter EX4 4QD, UK
cDepartment of Chemistry, University of St Andrews, St Andrews, Fife KY16 9ST, UK
Received 7 January 2002; revised 1 March 2002; accepted 21 March 2002
AbstractÐThe synthesis and solid state conformations of a number of N,N0-linked carbazoles and indoles has been investigated. Using
xylyl-based linkers, the o, m and p-linked carbazoles and indoles 4±6, 8±10 and 12, 13 were prepared. Likewise, unsymmetrical derivatives
were also prepared. Investigation using X-ray crystallography showed that the heterocycles adopted either stretched or folded conformations
in the solid state. q 2002 Elsevier Science Ltd. All rights reserved.
1. Introduction
2. Results and discussion
Poly3N-vinylcarbazole), a polymer with photoconducting
properties, has attracted considerable attention because of
potential applications in xerography and electroimaging,
and the photophysical properties of the polymer have been
extensively investigated.1 Although the carbazole chromo-
phone itself does not form excimers, the polymer shows two
types of excimer ¯uorescence attributed to different
geometric arrangements of the aromatic rings. Thus, photo-
chemical studies on 1,n-di3carbazol-9-yl)alkanes 1 3nˆ3±5)
and 2,4-di3carbazol-9-yl)pentane as models for the polymer
unit have been carried out,2±5 as have studies on carbazolo-
phanes in which the aromatic rings are more rigidly ®xed,6,7
and the results interpreted in terms of the interaction
between the chromophores. Such an interaction between
aromatic rings is an important intermolecular attractive
force with wide-ranging implications in chemistry, biology
and materials science.8 In view of our long standing interest
in carbazoles,9 we have prepared a series of N,N0-linked
derivatives 2, together with the corresponding indoles 3
3Fig. 1), with a view to determining the relative orientation
of the aromatic rings in the solid state.10 Similar linked
carbazole derivatives have recently been investigated as
low molecular weight glasses.11
2.1. Synthesis
The ®rst linker, X, chosen for study was the xylyl linker.
Hence reaction of carbazole with a,a0-dibromo-ortho-
xylene in the presence of potassium hydroxide in DMSO,
conditions known to facilitate the N-alkylation of pyrroles
and indoles,12 gave the linked carbazole 4 in 71% yield. The
meta- and para-isomers 5 and 6 were prepared similarly,
and the naphthalene-linked derivative 7 was prepared from
1,8-bis3bromomethyl)naphthalene using sodium hydride as
base in DMF/THF. The three isomeric xylyl linked indoles
8±10 were prepared in a similar manner to their carbazole
analogues, and the simple 1,5-diindolyl pentane 11 was
readily obtained from 1,5-diiodopentane 3Fig. 2). In order
to change the electronic properties of the heterocyclic
rings, 5-nitro- and 5-methoxy-indole were used as starting
materials. Reaction of 5-nitroindole with KOH in DMSO
gave a bright red anion which reacted with a,a0-dibromo-
para-xylene to give the linked indole 12 in 67% yield. The
5-methoxyindole derivative 13 was prepared similarly.
Keywords: polycyclic heterocyclic compounds; indoles; conformation;
X-ray crystallography.
p
Corresponding author. Present address: School of Chemistry, University
of Exeter, Stocker Road, Exeter EX4 4QD, UK. Fax: 144-1392-263434;
e-mail: c.j.moody@ex.ac.uk
Present address: Department of Chemistry, University of St Andrews,
St Andrews, Fife KY16 9ST, UK.
²
Figure 1.
0040±4020/02/$ - see front matter q 2002 Elsevier Science Ltd. All rights reserved.
PII: S0040-4020302)00344-7

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J. Bloxham et al. / Tetrahedron 58 32002) 3709±3720
Figure 2. Symmetrical linked carbazoles and indoles.
Since all of the above examples are symmetrical, it was
decided to prepare some unsymmetrical derivatives in
which the electronic properties of the heterocyclic rings
differed. Again the para-xylyl linker was used. Reaction
of 5-nitroindole with 2 equiv. of the xylyl dibromide gave
the mono bromide 14 in 34% yield together with a similar
amount of the symmetrical compound 12, readily separated
by chromatography. Subsequent reaction of bromide
with either 5-methoxyindole or carbazole gave the unsym-
metrical para-xylyl linked compounds 15 and 16 3Scheme 1).
Other linkers were also explored on the basis that these
might affect the overall conformation of the molecule.
Nagao and co-workers have shown that the nature of the
linker does indeed have a profound in¯uence on the confor-
mation of non-rigid molecules containing linked rings.13,14
Thus, it was shown that two linked aromatic rings could
adopt either a folded or stretched conformation according
to the nature of the linker 3carboxylate or sulfonate
ester). In order to investigate this in the indole and carba-
zole series, the known 2-3indol-l-yl)ethanol 1715 and
Scheme 1. Reagents and conditions: 3i) a,a0-dibromo-para-xylene 32 equiv.) KOH, DMSO 334%), 3ii) 5-methoxyindole, KOH, DMSO 347%), 3iii) carbazole,
KOH, DMSO 374%).

J. Bloxham et al. / Tetrahedron 58 32002) 3709±3720
3711
Scheme 2. Reagents and conditions: 3i) PhCOCl, Et3N, CH2Cl2 356%) or 4-NO2±C6H4COCl, Et3N, CH2Cl2 389%); 3ii) PhSO2Cl, Et3N, CH2Cl2 395%),
3iii) terephthaloyl chloride, Et3N, CH2Cl2 357%).
2-3carbazol-9-yl)ethanol 2116 were chosen as starting
materials; both were readily prepared by reaction of the
parent heterocycle with 2-chloroethanol. Hence, a range of
esters 18±20 and 22, 23 was readily prepared in good
yield from the alcohols 17 and 21 as outlined in Schemes
2 and 3.
Finally, the more complex linked carbazole 26 was prepared
Scheme 3. Reagents and conditions: 3i) PhCOCl, Et3N, CH2Cl2 364%) or 4-NO2±C6H4COCl, Et3N, CH2Cl2 379%); 3ii) PhSO2Cl, Et3N, CH2Cl2 394%).
Scheme 4. Reagents and conditions: 3i) a,a0-dibromo-para-xylene 30.5 equiv.), K2CO3, acetone 329%); 3ii) a,a0-dibromo-para-xylene 31.25 equiv.), NaH,
DMF 338%); 3iii) 24 31 equiv.), 25 32 equiv.), KOH, DMSO 386%).

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J. Bloxham et al. / Tetrahedron 58 32002) 3709±3720
Figure 3. X-Ray crystal structure of 1,5-di3indol-1-yl)pentane 11 showing 3a) the zig-zag conformation of the alkyl chain, and 3b) the relative orientation of
the heteroaromatic rings.
in the expectation that it might act as a molecular tweezer.17
The two building blocks 24 and 25 were both prepared from
a,a0-dibromo-para-xylene by reaction with 5-hydroxy-
indole and carbazole, respectively 3Scheme 4). Coupling
the two fragments 24 and 25 3in the ratio 1:2) then
gave the desired linked carbazole 26 in excellent yield
386%). Unfortunately, no suitable crystals of 26 could
be obtained, so its solid state conformation remains
unknown.
2.2. X-Ray crystal structures
In order to study the solid state conformations of the linked
hetereocycles, a number of X-ray crystallographic analyses
Figure 4. 3a) X-Ray crystal structure of 1,2-di[3carbazol-9-yl)methyl]benzene 4 showing 3b) the helicopter-blade conformation.
Figure 5. 3a) X-Ray crystal structure of 1,4-di[3carbazol-9-yl)methyl]benzene 6 showing 3b) the anti-parallel carbazole rings.

J. Bloxham et al. / Tetrahedron 58 32002) 3709±3720
3713
Figure 6. 3a) X-Ray crystal structure of 1,2-di[3indol-1-yl)methyl]benzene 8; 3b) X-ray crystal structure of 1,4-di[3indol-1-yl)methyl]benzene 10 showing its
similar conformation to the carbazole analogue 6.
Figure 7. X-Ray crystal structures of 3a) 1,4-di[35-nitroindol-1-yl)methyl]benzene 12 and 3b) 1,4-di[35-methoxyindol-1-yl)methyl]benzene 13.
were performed. The ®rst compound investigated was the
C5-linked indole 11. In this molecule, the ¯oppy alkyl chain
adopts a normal zig-zag conformation, although interest-
ingly the planes of the terminal indole rings lie almost at
although the meta-isomers 5 and 9 did not. In the linked
carbazole 4, there is considerable steric repulsion between
the carbazole rings which causes them to point away from
each other, although they are not coplanar, and adopt a
helicopter-blade type conformation 3Fig. 4). In the para-
isomer 6, the planes of the benzene and carbazole rings
are almost at right angles in an H-shape with the two carba-
zoles pointing away from each other with their planes
almost parallel 3Fig. 5).
Ê
right angles to each other at a distance of ca. 7.5 A 3Fig. 3).
The ortho- and para-xylyl linked carbazoles and indoles 4,
6, 8 and 10 also gave suitable crystals for X-ray analysis,
In the linked indole 8, the indole rings appear to twist as far
away as possible from each other 3Fig. 6a), although the
para-isomer 10 adopts an almost identical solid state
conformation to its carbazole analogue 6 3Fig. 6b).
However, the other para-xylyl linked indoles 12 and 13
showed signi®cantly different conformations in the crystal.
Whereas the nitro-substituted compound 12 adopted a more
or less identical conformation to the unsubstituted indole 10
and the carbazole analogue 6, the methoxy-substituted
compound 13 is somewhat different 3Fig. 7).
The crystal structure of the unsymmetrical para-xylyl
linked compound 16 is also markedly different 3Fig. 8). In
this case, the rings do not point in opposite directions 3as in
Figure 8. X-Ray crystal structure of 1-[4-3carbazol-9-yl)methyl]benzyl-5-
nitroindole 16.

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J. Bloxham et al. / Tetrahedron 58 32002) 3709±3720
Figure 9. X-Ray crystal structures of the 2-3indol-1-yl) esters 3a) 2-3indol-1-yl)ethyl 4-nitrobenzoate 18b and 3b) di-[2-3indol-1-yl)ethyl] terephthalate 20.
the symmetrical cases) and one heterocyclic ring apparently
lies over the other.
which the rings are connected by ester linkages show the
expected stretched conformation.
The esters 18b, 20 and 22 were also investigated by
crystallography. The indole derived para-nitrobenzoate
adopted a conformation 3Fig. 9a) reminiscent of one that
is described by Nagao as a `non-stacked conformation'
since it is not fully stretched.13,14 On the other hand, the
terephthaloyl diester 20 adopted the stretched conformation,
as perhaps expected on the basis of Nagao's work 3Fig. 9b).
Unfortunately, the corresponding sulfonate 19 did not give
suitable crystals.
4. Experimental
4.1. General
Commercially available reagents were used throughout
without further puri®cation; solvents were dried by standard
procedures. Ether refers to diethyl ether, and light petroleum
to the fraction with bp 40±608C. Analytical thin layer
chromatography was carried out using aluminium-backed
plates coated with Merck Kieselgel 60 GF254. Plates were
visualised under UV light 3at 254 and/or 360 nm). Flash
chromatography was carried out using Merck Kieselgel 60
H silica or Matrex silica 60.
The esters 22a and 22b also adopted the non-stacked
conformation 3Fig. 10) and, since the two structures are
more or less identical, an electronic effect of the nitro
group in in¯uencing the conformation can be ruled out.
Fully characterised compounds were chromatographically
homogeneous. IR spectra were recorded in the range
4000±600 cm21 using a Nicolet FT-205 spectrometer,
3. Conclusions
1
with internal calibration. H and 13C NMR spectra were
A number of linked carbazoles and indoles have been
synthesised, and although not all of them gave suitable
crystals, a number of solid state conformations have
been determined by X-ray crystallography. In general,
the symmetrical para-xylyl-linked derivatives adopted the
stretched conformation, whereas the unsymmetrical
example preferred a folded conformation. Compounds in
recorded in deuteriochloroform 3unless otherwise stated)
using Bruker AC-250 and Bruker DPX-400 instruments.
High- and low-resolution mass spectra were recorded on
a Kratos MS80 instrument, and at the EPSRC Mass
Spectrometry Service at Swansea.
4.1.1. 1,2-Di[/carbazol-9-yl)methyl]benzene 4. Carbazole
Figure 10. X-Ray crystal structures of 3a) 2-3carbazol-9-yl)ethyl benzoate 22a, and 3b) 2-3carbazol-9-yl)ethyl 4-nitrobenzoate 22b.

J. Bloxham et al. / Tetrahedron 58 32002) 3709±3720
3715
31.67 g, 10.0 mmol) was added to a suspension of potassium
hydroxide 32.24 g, 40.0 mmol) in DMSO 315 mL) under
nitrogen. The mixture was stirred for 0.75 h after which
time a,a0-dibromo-o-xylene 31.32 g, 5.0 mmol) was
added. The reaction was stirred overnight. Addition of
water 320 mL) caused precipitation of the crude product.
The solid was ®ltered off, dissolved in dichloromethane
3250 mL) and washed with brine 36£100 mL). Column
chromatography 31:1 dichloromethane±light petroleum)
yielded the title compound 31.55 g, 71%) as a colourless
solid, mp 227±2288C 3toluene) 3lit.,11 mp 2278C); nmax
3CH2Cl2) 1486, 1454, 1326, 1216 cm21; dH 3250 MHz;
CDCl3) 8.17 34H, d, Jˆ7.7 Hz, Ar-4H), 7.44 34H, dd,
Jˆ8.1, 7.7 Hz, aryl H), 7.29 34H, t, Jˆ7.4 Hz, aryl H),
7.20 34H, d, Jˆ8.1 Hz, Ar-2H), 7.05 32H, dd, Jˆ5.4,
3.6 Hz, xylyl H), 6.74 32H, dd, Jˆ5.4, 3.6 Hz, xylyl H),
5.45 34H, s, NCH2); dC 362.9 MHz; CDCl3) 140.6 3C),
133.6 3C), 128.0 3CH), 126.7 3CH), 126.0 3CH), 123.2
3C), 120.6 3CH), 119.5 3CH), 108.9 3CH), 44.4 3NCH2).
tion of carbazole 3322 mg, 1.93 mmol) and DMF 30.15 mL,
1.93 mmol) in THF 35 mL) was added to sodium hydride
3116 mg, 4.8 mmol) under nitrogen. After 0.25 h 1,8-
bis3bromomethyl)naphthalene 3303 mg, 0.96 mmol) was
added. The reaction was heated at 508C for 4 h. The solvent
was removed under reduced pressure. Puri®cation by
column chromatography 33:10 dichloromethane±light
petroleum) yielded the title compound 3355 mg, 76%) as a
colourless solid, mp 268±2708C; 3Found: C, 88.4; H, 5.3; N,
5.6. C36H26N2 requires C, 88.8; H, 5.4; N, 5.8%); nmax
3CH2Cl2) 1599, 1487, 1457, 1222 cm21; dH 3250 MHz;
CDCl3) 8.20 34H, d, Jˆ7.5 Hz, aryl H), 7.78 32H, d, Jˆ
8.0 Hz, naphthyl H), 7.49±7.42 34H, m, aryl H), 7.34±
7.30 34H, m, aryl H), 7.30 34H, d, Jˆ7.8 Hz, aryl H), 7.18
32H, m, naphthyl H), 6.74 32H, d, Jˆ7.2 Hz, naphthyl H),
6.35 34H, s, NCH2); dC 362.9 MHz; CDCl3) 145.1 3C),
140.8 3C), 137.3 3C), 135.2 3C), 134.2 3naphthyl CH),
130.7 3CH), 130.1 3naphthyl CH), 129.7 3naphthyl CH),
127.7 3C), 125.1 3CH), 124.2 3CH), 113.8 3CH), 53.0
3NCH2); m/z 3EI) 486 3M1, 6%), 317 322), 267 342), 167
374), 155 380), 51 3100).
4.1.2. 1,3-Di[/carbazol-9-yl)methyl]benzene 5. Carbazole
3501 mg, 3.00 mmol) was added to a suspension of potas-
sium hydroxide 3672 mg, 12.0 mmol) in DMSO 310 mL)
under nitrogen. The mixture was stirred for 0.75 h after
which time a,a0-dibromo-m-xylene 3396 mg, 1.50 mmol)
was added. The reaction was stirred overnight. Addition
of water 350 mL) caused precipitation of the crude product;
the solid was ®ltered and washed with water and brine.
Column chromatography 31:1 dichloromethane±light petro-
leum) yielded the title compound 3445 mg, 68%) as a
colourless solid, mp 208±2108C 3lit.,11 mp 2038C);
3Found: C, 87.8; H, 5.5; N, 6.3. C32H24N2 requires C,
88.0; H, 5.5; N, 6.4%); nmax 3CH2Cl2) 1610, 1513, 1484,
1463, 1439, 1317, 1187 cm21; dH 3250 MHz; CDCl3) 8.14
34H, dd, Jˆ7.0, 1.8 Hz, aryl H), 7.41 34H, ddd, Jˆ7.0, 1.8,
1.1 Hz, aryl H), 7.29±7.23 38H, m, aryl H), 7.13±6.94 34H,
m, aryl H), 5.40 34H, s, NCH2); dC 362.9 MHz; CDCl3)
140.7 3C), 137.8 3C), 129.3 3CH), 125.8 3CH), 125.5
3CH), 124.6 3CH), 123.0 3C), 120.3 3CH), 119.2 3CH),
108.8 3CH), 46.3 3NCH2).
4.1.5. 1,2-Di[/indol-1-yl)methyl]benzene 8. Indole 31.50 g,
12.8 mmol) was added to a suspension of potassium
hydroxide 32.87 g, 51.3 mmol) in DMSO 325 mL) under
an atmosphere of nitrogen. The mixture was stirred for
1 h, then a,a0-dibromo-o-xylene 31.70 g, 6.4 mmol) was
added with external cooling. The mixture was stirred
overnight. Water 310 mL) was added and extracted with
dichloromethane 33£90 mL), the organics were then washed
with brine 33£100 mL) and dried 3MgSO4). Column
chromatography 31:49 ether±light petroleum) yielded the
title compound 31.66 g, 77%) as a colourless solid, mp
114±1158C 3ethanol); 3Found: M1, 336.1628. C24H20N2
requires 336.1626); nmax 3CH2Cl2) 1514, 1484, 1463,
1319, 1269 cm21; dH 3250 MHz; CDCl3) 7.70±7.66 32H,
m, aryl H), 7.26±7.12 38H, m, aryl H), 6.98 32H, d,
Jˆ3.2 Hz, Ar-2H), 6.91±6.87 32H, m, aryl H), 6.58 32H,
d, Jˆ3.2 Hz, Ar-3H), 5.24 34H, s, NCH2); dC 362.9 MHz;
d6DMSO) 136.3 3C), 134.8 3C), 128.8 3C), 128.4 3CH),
128.3 3CH), 127.8 3CH), 121.9 3CH), 121.2 3CH), 119.8
3CH), 109.5 3CH), 102.2 3CH), 47.6 3NCH2); m/z 3EI) 336
3M1, 27%), 218 3100), 104 38).
4.1.3. 1,4-Di[/carbazol-9-yl)methyl]benzene 6. Carbazole
3500 mg, 2.99 mmol) was added to a suspension of potas-
sium hydroxide 3671 mg, 12.0 mmol) in DMSO 310 mL)
under nitrogen. The mixture was stirred for 0.75 h after
which time a,a0-dibromo-p-xylene 3395 mg, 1.50 mmol)
was added. The reaction was stirred overnight. Addition
of water 350 mL) caused precipitation of the crude product;
the solid was ®ltered and washed with water and brine.
Column chromatography 31:1 dichloromethane±light petro-
leum) yielded the title compound 3483 mg, 74%) as a
colourless solid, mp 246±2488C 3toluene) 3lit.,11 mp
2658C); 3Found: C, 87.8; H, 5.5; N, 6.3. C32H24N2 requires
C, 88.0; H, 5.6; N, 6.4%); nmax 3CH2Cl2) 1486, 1460, 1333,
1326 cm21; dH 3250 MHz; CDCl3) 8.09 34H, dd, Jˆ7.8,
0.9 Hz, aryl H), 7.39 34H, ddd, Jˆ7.4, 7.5, 1.0 Hz, aryl
H), 7.30 34H, d, Jˆ7.4 Hz, aryl H), 7.22 34H, ddd, Jˆ7.8,
7.3, 1.0 Hz, aryl H), 7.02 34H, s, xylyl H), 5.45 34H, s,
NCH2); dC 3100 MHz; CDCl3) 140.5 3C), 136.5 3C), 126.8
3CH), 125.8 3CH), 122.9 3C), 120.3 3CH), 119.2 3CH), 108.8
3CH), 46.1 3NCH2).
4.1.6. 1,3-Di[/indol-1-yl)methyl]benzene 9. Indole 31.50 g,
12.8 mmol) was added to a suspension of potassium
hydroxide 32.87 g, 51.3 mmol) in DMSO 325 mL) under
an atmosphere of nitrogen. The mixture was stirred for
1 h, then a,a0-dibromo-m-xylene 31.70 g, 6.4 mmol) was
added with external cooling. The mixture was stirred over-
night. Water 320 mL) was added and extracted with
dichloromethane 33£80 mL), the organics were then washed
with brine 34£100 mL) and dried 3MgSO4). Column chro-
matography 3dichloromethane) yielded the title compound
31.63 g, 75%) as a colourless solid, mp 112±1138C
3ethanol); 3Found: C, 85.7; H, 5.8; N, 8.0. C24H20N2 requires
C, 85.7; H, 6.0; N, 8.3%); nmax 3CH2Cl2) 1514, 1484, 1463,
1334, 1317, 1270 cm21; dH 3250 MHz; CDCl3) 7.69±7.66
32H, m, aryl H), 7.26±7.11 36H, m, aryl H), 7.09 32H, d,
Jˆ3.3 Hz, Ar-2H), 6.98±6.95 34H, m, aryl H), 6.56 32H, d,
Jˆ3.3 Hz, Ar-3H), 5.26 34H, s, NCH2); dC 362.9 MHz;
CDCl3) 138.1 3C), 136.0 3C), 129.2 3CH), 128.7 3C),
128.1 3CH), 126.0 3CH), 125.1 3CH), 121.7 3CH), 120.9
4.1.4. 1,8-Di[/carbazol-9-yl)methyl]naphthalene 7. A solu-

3716
J. Bloxham et al. / Tetrahedron 58 32002) 3709±3720
3CH), 119.5 3CH), 109.6 3CH), 101.7 3CH), 49.9 3NCH2);
m/z 3EI) 336 3M1, 100%), 220 365), 168 316), 104 316).
3CH), 109.6 3CH), 54.7 3NCH2); m/z 3EI), 277 322%), 116
322), 91 349), 84 368), 49 3100).
4.1.7. 1,4-Di[/indol-1-yl)methyl]benzene 10. Indole 34.0 g,
34.2 mmol) was added to a stirred solution of powdered
potassium hydroxide 37.66 g, 136.8 mmol) in DMSO
350 mL) under nitrogen. The mixture was stirred for 1 h
after which a,a0-dibromo-p-xylene 34.51 g, 17.1 mmol)
was added with external cooling. The mixture was stirred
overnight. Water 350 mL) was added and the mixture
extracted with dichloromethane 33£80 mL). The combined
organics were washed with brine 35£100 mL) and dried
3MgSO4). The solvent was removed under reduced pressure.
Column chromatography 3dichloromethane) yielded the
title compound 35.2 g, 91%)as a colourless solid, mp 127±
1288C 3lit.,18 mp 1158C 3ethanol)); nmax 3CH2Cl2) 1514,
1484, 1463, 1318, 1184 cm21; dH 3250 MHz; CDCl3) 7.65
32H, dd, Jˆ6.6, 1.5 Hz, aryl H), 7.25 32H, d, Jˆ6.8 Hz, aryl
H), 7.20±7.08 36H, m, aryl H), 7.03 34H, s, xylyl H), 6.54
32H, dd, Jˆ3.6, 0.8 Hz, Ar-3H), 5.28 34H, s, NCH2); dC
362.9 MHz; CDCl3) 137.0 3C), 136.5 3C), 128.7 3C), 128.2
3CH), 127.1 3CH), 121.7 3CH), 121.0 3CH), 119.6 3CH),
109.6 3CH), 101.8 3CH), 49.7 3NCH2).
4.1.10. 1,4-Di[/5-methoxyindol-1-yl)methyl]benzene 13.
5-Methoxyindole 3294 mg, 2.0 mmol) was added to a
suspension of potassium hydroxide 3450 mg, 8.0 mmol) in
DMSO 35 mL) under nitrogen. The mixture was stirred for
0.75 h, then a,a0-dibromo-p-xylene 3264 mg, 1.0 mmol)
was added. The reaction mixture was stirred overnight.
Water 330 mL) was added and the mixture extracted with
dichloromethane 32£100 mL). The combined organics were
then washed with brine 35£100 mL) and dried 3MgSO4).
The solvent was removed under reduced pressure. Column
chromatography 31:1 dichloromethane±light petroleum)
yielded the title compound 3294 mg, 74%) as a colourless
solid, mp 164±1658C 3toluene); 3Found: C, 78.8; H, 6.0; N,
7.0. C26H24N2O2 requires C, 78.8; H, 6.1; N, 7.1%); nmax
3CH2Cl2) 1487, 1422, 1240, 1152 cm21; dH 3360 MHz;
CDCl3) 7.11±7.09 34H, m, aryl H), 7.06 32H, d, Jˆ
3.0 Hz, Ar-2H), 6.99 34H, s, xylyl H), 6.80 32H, dd, Jˆ
8.8, 2.5 Hz, aryl H), 6.44 32H, d, Jˆ3.0 Hz, Ar-3H), 5.23
34H, s, NCH2), 3.83 36H, s, OCH3); dC 3100 MHz; CDCl3)
154.1 3C), 137.1 3C), 131.6 3C), 129.1 3C), 128.7 3CH),
127.3 3CH), 112.0 3CH), 110.4 3CH), 102.4 3CH), 101.3
3CH), 55.8 3OCH3), 49.9 3NCH2); m/z 3EI) 396 3M1,
100%), 250 342), 146 365), 104 335).
4.1.8. 1,5-Di/indol-1-yl)pentane 11. Indole 34.00 g,
34.2 mmol) was added to a suspension of potassium
hydroxide 37.66 g, 136.8 mmol) in DMSO 360 mL) under
nitrogen. After 0.75 h, 1,5-diiodopentane 35.40 g, 17.1
mmol) was added with external cooling. After 16 h, water
320 mL) was added and the mixture extracted with dichloro-
methane 33£80 mL). The combined organics were washed
with water 33£80 mL), brine 33£80 mL) and dried
3MgSO4). The solvent was removed under reduced pressure.
Puri®cation by column chromatography 31:1 dichloro-
methane±light petroleum) yielded the title compound
38.2 g, 80%) as a colourless crystalline solid, mp 84±868C
3lit.,18 mp 818C); nmax 3Nujol) 1510, 1446, 1438, 1317,
746 cm21; dH 3250 MHz; CDCl3) 7.77 32H, d, Jˆ7.4 Hz,
aryl H), 7.43±7.21 36H, m, aryl H), 7.09 32H, d,
Jˆ3.3 Hz, Ar-2H), 6.60 32H, d, Jˆ3.3 Hz, Ar-3H), 4.09
34H, t, Jˆ7.0 Hz, NCH2), 1.89 34H, m, NCH2CH2) 1.41±
1.34 32H, m, NCH2CH2CH2); dC 362.9 MHz; CDCl3) 136.0
3C), 128.4 3C), 127.8 3CH), 121.5 3CH), 121.1 3CH), 119.3
3CH), 109.4 3CH), 101.1 3CH), 46.1 3NCH2), 29.9
3NCH2CH2), 24.5 3NCH2CH2CH2).
4.1.11. 1-/4-Bromomethyl)benzyl-5-nitroindole 14. 5-Nitro-
indole 3486 mg, 3.0 mmol) was added to a suspension
of potassium hydroxide 3670 mg, 12.0 mmol) in DMSO
320 mL) under nitrogen. The reaction was stirred for
0.75 h, then a,a0-dibromo-p-xylene 31.56 g, 6.0 mmol)
was added and the reaction stirred for 3 h. Water 340 mL)
was added and extracted with dichloromethane 33£80 mL).
The combined organics were then washed with brine
34£100 mL) and dried 3MgSO4). Column chromatography
33:2 dichloromethane±light petroleum) yielded the title
compound 3350 mg, 34%) as a yellow solid, mp 128±
1298C; 3Found: M1, 344.0155. C16H1379BrN2O2 requires
344.0161); nmax 3CH2Cl2) 1518, 1336, 1256, 1070, 774
cm21; dH 3250 MHz; CDCl3) 8.58 31H, d, Jˆ2.2 Hz,
Ar-4H), 8.05 31H, dd, Jˆ9.1, 2.2 Hz, Ar-6H), 7.34 32H, d,
Jˆ8.1 Hz, xylyl H), 7.28 31H, d, Jˆ3.2 Hz, Ar-2H), 7.27±
7.25 31H, d, Jˆ9.2 Hz, Ar-7H), 7.07 32H, d, Jˆ8.0 Hz, xylyl
H), 6.73 31H, d, Jˆ3.2 Hz, Ar-3H), 5.36 32H, s, NCH2), 4.45
32H, s, BrCH2); dC 362.9 MHz; CDCl3) 142.0 3C), 139.0
3C), 137.7 3C), 136.5 3C), 131.4 3CH), 129.6 3CH), 127.9
3C), 127.1 3CH), 118.2 3CH), 117.4 3CH), 109.5 3CH), 104.5
3CH), 50.2 3NCH2), 32.7 3BrCH2); m/z 3EI) 346/344 3M1,
29%), 265 312), 185 339), 183 341), 104 3100), 91 329), 78
318).
4.1.9. 1,4-Di[/5-nitroindol-1-yl)methyl]benzene 12. 5-Nitro-
indole 3486 mg, 3.0 mmol) was added to a stirred suspension
of potassium hydroxide 3672 mg, 12.0 mmol) in DMSO
310 mL) under nitrogen. The mixture was stirred for 0.75 h,
then a,a0-dibromo-p-xylene 3396 mg, 1.5 mmol) was added.
The mixture was stirred overnight. Water 330 mL) was added
and the resultant suspension was ®ltered off. Column chroma-
tography 3dichloromethane) yielded the title compound
3428 mg, 67%) as a yellow solid, mp 205±2068C 3toluene);
3Found: C, 67.2; H, 4.1; N, 12.6. C24H18N4O4 requires C, 67.6;
H, 4.3; N, 13.1%); nmax 3CH2Cl2) 1518, 1336, 731 cm21; dH
3360 MHz; d6DMSO) 8.56 32H, d, Jˆ2.2 Hz, Ar-4H), 7.96
32H, dd, Jˆ9.1, 2.2 Hz, Ar-6H), 7.73 32H, d, Jˆ3.1 Hz,
Ar-2H), 7.64 32H, d, Jˆ9.1 Hz, Ar-7H), 7.17 34H, s, xylyl
H), 6.77 32H, d, Jˆ3.1 Hz, Ar-3H), 5.47 34H, s, NCH2); dC
3100 MHz; d6DMSO) 146.5 3C), 144.2 3C), 142.5 3C), 138.5
3CH), 133.1 3C), 133.0 3CH), 123.2 3CH), 122.1 3CH), 116.2
4.1.12. 1-[4-/5-Methoxyindol-1-yl)methyl]benzyl-5-nitro-
indole 15. 5-Methoxyindole 3122 mg, 0.83 mmol) was
added to a suspension of potassium hydroxide 3186 mg,
3.3 mmol) in DMSO 35 mL) under nitrogen. After 0.75 h,
the benzyl bromide 14 3300 mg, 0.87 mmol) was added. The
reaction was stirred overnight. Addition of water 315 mL)
and ®ltration gave the crude product. Column chroma-
tography 33:7 dichloromethane±light petroleum) yielded
the title compound 3160 mg, 47%) as a yellow solid, mp
117±1188C 3toluene); 3Found: M1, 411.1584. C25H21N3O3
requires 411.1583); nmax 3CH2Cl2) 3055, 1518, 1487, 1450,

J. Bloxham et al. / Tetrahedron 58 32002) 3709±3720
3717
1335, 1240, 1152, 1070 cm21; dH 3250 MHz; CDCl3) 8.59
31H, d, Jˆ2.2 Hz, Ar-4H3NO2)), 8.05 31H, dd, Jˆ9.1,
2.2 Hz, Ar-6H3NO2)), 7.26±7.23 32H, m, aryl H), 7.12±
7.06 33H, m, aryl H), 7.02 34H, d, Jˆ2.0 Hz, xylyl H),
6.82 31H, dd, Jˆ9.0, 2.4 Hz, Ar-6H3OMe)), 6.71 31H,
d, Jˆ3.2 Hz, Ar-3H3NO2)), 6.47 31H, d, Jˆ3.0 Hz,
Ar-3H3OMe)), 5.30 32H, s, NCH2), 5.24 32H, s, NCH2),
3.84 33H, s, OCH3); dC 362.9 MHz; CDCl3) 154.1 3C),
141.6 3C), 138.9 3C), 137.7 3C), 135.6 3C), 131.4 3CH),
129.1 3C), 128.7 3CH), 127.9, 127.2 3CH), 127.1 3CH),
118.2 3CH), 117.4 3CH), 112.0 3CH), 110.3 3CH), 109.5
3CH), 104.4 3CH), 102.7 3CH), 101.4 3CH), 56.8 3OCH3),
50.1 3NCH2), 49.8 3NCH2); m/z 3EI) 411 313%), 186 314),
155 334), 78 343), 44 347), 31 3100).
7.2 mmol) in dichloromethane 35 mL) under an atmosphere
of nitrogen. The mixture was stirred overnight. The solvent
was removed under reduced pressure and the residue
puri®ed by column chromatography 3dichloromethane) to
yield the title compound 3668 mg, 56%) as a colourless
solid, mp 103±1048C 3toluene); 3Found: C, 76.8; H, 5.7;
N, 5.1. C17H15NO2 requires C, 77.0; H, 5.7; N, 5.3%);
nmax 3CH2Cl2) 1718, 1270, 741, 710, 668 cm21; dH 3250
MHz; CDCl3) 7.96 32H, d, Jˆ7.2 Hz, aryl H), 7.65 31H, d,
Jˆ7.8 Hz, aryl H), 7.55 31H, d, Jˆ7.3 Hz, aryl H), 7.45±
7.39 33H, m, aryl H), 7.28±7.11 33H, m, aryl H), 6.55 31H,
d, Jˆ3.2 Hz, Ar-3H), 4.65 32H, t, Jˆ5.5 Hz, CH2CH2), 4.52
32H, t, Jˆ5.5 Hz, CH2CH2); dC 362.9 MHz; CDCl3) 166.0
3CvO), 135.9 3C), 133.0 3CH), 129.4 3CH), 128.5 3C),
128.2 3CH), 127.9 3C), 127.8 3CH), 121.5 3CH), 120.9
3CH), 119.4 3CH), 109.1 3CH), 101.7 3CH), 63.4 3OCH2),
44.7 3NCH2); m/z 3EI) 265 3M1, 31%), 143 3100), 130 395),
105 327), 77 351).
4.1.13. 1-[4-/Carbazol-9-yl)methyl]benzyl-5-nitroindole
16. Carbazole 3121 mg, 0.72 mmol) was added to a suspen-
sion of potassium hydroxide 3162 mg, 2.90 mmol) in
DMSO 35 mL) under nitrogen. After 0.75 h, the benzyl
bromide 14 3250 mg, 0.72 mmol) was added. The reaction
was stirred overnight. Water 315 mL) was added to give the
crude product as a precipitate. Filtration followed by
column chromatography 33:7 dichloromethane±light petro-
leum) yielded the title compound 3230 mg, 74%) as a yellow
solid, mp 184±1858C 3toluene); 3Found: M1, 431.1638.
C28H21N3O2 requires 431.1634); nmax 3CH2Cl2) 1517,
1485, 1453, 1335, 1070 cm21; dH 3250 MHz; CDCl3) 8.59
31H, d, Jˆ2.1 Hz, indole-4H), 8.13 32H, d, Jˆ7.7 Hz,
Ar-4H), 8.05 31H, dd, Jˆ9.1, 2.2 Hz, indole-6H), 7.43
32H, dt, Jˆ1.0, 7.6 Hz, aryl H), 7.31±7.21 36H, m, aryl
H), 7.09 32H, d, Jˆ8.1 Hz, aryl H), 6.97 32H, d, Jˆ
8.1 Hz, aryl H), 6.70 31H, d, Jˆ3.2 Hz, indole-3H), 5.49
32H, s, NCH2), 5.29 32H, s, NCH2); dC 3100 MHz; CDCl3)
142.2 3C), 140.9 3C), 139.4 3C), 137.7 3C), 135.9 3C), 131.8
3CH), 128.3 3C), 127.6 3CH), 127.5 3CH), 126.3 3CH), 123.5
3C), 120.9 3CH), 119.8 3CH), 118.7 3CH), 117.9 3CH), 109.9
3CH), 109.1 3CH), 104.9 3CH), 50.6 3CH2), 46.5 3CH2); m/z
3EI) 431 3M1, 42%), 267 346), 236 332), 155 367), 31 3100).
4.1.16. 2-/Indol-1-yl)ethyl 4-nitrobenzoate 18b. p-Nitro-
benzoyl chloride 3835 mg, 4.5 mmol) was added to a solu-
tion of the alcohol 17 3483 mg, 3.0 mmol) and triethylamine
30.48 mL, 4.5 mmol) in dichloromethane 35 mL) under an
atmosphere of nitrogen. The mixture was stirred overnight.
The solvent was removed under reduced pressure and the
residue puri®ed by column chromatography 33:1 dichloro-
methane±light petroleum) to yield the title compound
3828 mg, 89%) as a yellow solid, mp 103±1048C 3light
petroleum); 3Found: M1, 310.0954. C17H14N2O4 requires
310.0953); nmax 3CH2Cl2) 2254, 1728, 1531, 1351, 1270,
740 cm21; dH 3250 MHz; CDCl3) 8.23 32H, d, Jˆ8.7 Hz,
benzoyl H), 8.05 32H, d, Jˆ8.8 Hz, benzoyl H), 7.66 31H,
d, Jˆ7.8 Hz, Ar-4H), 7.41 31H, d, Jˆ8.2 Hz, aryl H), 7.24
31H, d, Jˆ5.6 Hz, aryl H), 7.21±7.11 32H, m, aryl H), 6.56
31H, d, Jˆ0.6 Hz, Ar-3H), 4.69 32H, d, Jˆ5.3 Hz, CH2),
4.57 32H, d, Jˆ5.4 Hz, CH2); dC 362.9 MHz; CDCl3)
164.8 3CvO), 150.8 3C), 136.0 3C), 134.8 3C), 130.7
3benzoyl CH), 128.4 3C), 127.6 3CH), 123.5 3benzoyl
CH), 121.8 3CH), 121.2 3CH), 119.7 3CH), 109.0 3CH),
102.2 3CH), 64.4 3OCH2), 44.8 3NCH2); m/z 3EI) 310
3M1, 31%), 267 310), 180 349), 143 345), 130 3100).
4.1.14. 2-/Indol-1-yl)ethanol 17. Indole 32.34 g, 20.0
mmol) was added to a suspension of potassium hydroxide
34.48 g, 80.0 mmol) in DMSO 320 mL) under an atmos-
phere of nitrogen. The mixture was stirred for 1 h, then
2-chloroethanol 32.0 g, 25.0 mmol) was added with external
cooling. The mixture was stirred overnight. Water 320 mL)
was added and the mixture was extracted with dichloro-
methane 33£80 mL). The combined organics were then
washed with brine 36£100 mL) and dried 3MgSO4). Column
chromatography 3dichloromethane) yielded the title
compound as a pale yellow oil 32.57 g, 71%), 3lit.,15 oil),
nmax 3®lm) 3367 3br), 2935, 1510, 1464, 1315, 1064,
742 cm21; dH 3250 MHz; CDCl3) 7.64 31H, d, Jˆ7.9 Hz,
Ar-4H), 7.38 31H, d, Jˆ8.3 Hz, Ar-7H), 7.24 31H, dd,
Jˆ8.2, 7.7 Hz, aryl H), 7.20±7.09 32H, m, aryl H), 6.52
31H, d, Jˆ3.0 Hz, Ar-3H), 4.12 32H, t, Jˆ5.3 Hz, OCH2),
3.76 32H, t, Jˆ5.2 Hz, NCH2), 1.80 31H, s br, OH); dC
362.9 MHz; CDCl3) 136.0 3C), 128.5 3C), 128.4 3CH),
121.6 3CH), 121.0 3CH), 119.5 3CH), 109.3 3CH), 101.4
3CH), 61.8 3OCH2), 48.6 3NCH2).
4.1.17. 2-/Indol-1-yl)ethyl benzenesulfonate 19. Benzene-
sulfonyl chloride 30.86 mL, 6.75 mmol) was added to a
solution of the alcohol 17 3543 mg, 3.37 mmol) and triethyl-
amine 30.72 mL, 6.75 mmol) in dichloromethane 35 mL)
under an atmosphere of nitrogen. The mixture was stirred
overnight. The solvent was removed under reduced pressure
and the residue puri®ed by column chromatography 33:2
dichloromethane±light petroleum) to yield the title com-
pound 3860 mg, 95%) as a colourless solid, mp 72±738C;
3Found: C, 63.9; H, 4.7; N, 4.5. C16H15NO3S requires C,
63.8; H, 5.0; N, 4.6%); nmax 3CH2Cl2) 1365, 1188, 1178,
907 cm21; dH 3360 MHz; CDCl3) 7.62±7.58 33H, m, aryl
H), 7.50 31H, t, Jˆ7.5 Hz, aryl H), 7.33 32H, t, Jˆ7.9 Hz,
aryl H), 7.18±7.07 33H, m, aryl H), 7.03 31H, d, Jˆ3.2 Hz,
Ar-2H), 6.46 31H, d, Jˆ3.2 Hz, Ar-3H), 4.40 32H, t, Jˆ
5.1 Hz, CH2CH2), 4.32 32H, t, Jˆ5.1 Hz, CH2CH2); dC
3100 MHz; CDCl3) 136.1, 135.5, 134.1 3CH), 129.7 3CH),
129.5, 128.4 3CH), 127.9 3CH), 122.3 3CH), 121.5 3CH),
120.1 3CH), 109.2 3CH), 102.6 3CH), 68.5 3OCH2), 45.5
3NCH2); m/z 3EI) 301 3M1, 30%), 143 316), 130 3100), 91
332), 77 318).
4.1.15. 2-/Indol-1-yl)ethyl benzoate 18a. Benzoyl chloride
30.78 mL, 6.8 mmol) was added to a solution of the
alcohol 17 3725 mg, 4.5 mmol) and triethylamine 31.0 mL,

3718
J. Bloxham et al. / Tetrahedron 58 32002) 3709±3720
4.1.18. Di-[2-/indol-1-yl)ethyl] terephthalate 20. Tereph-
thaloyl chloride 3391 mg, 1.93 mmol) was added to a
solution of the alcohol 17 3620 mg, 3.85 mmol) and triethyl-
amine 30.5 mL) in dichloromethane 34 mL). The mixture
was stirred overnight. The solvent was removed under
reduced pressure. Column chromatography 31:1 ether±
dichloromethane) yielded the title compound 3497 mg,
57%) as a colourless solid, mp 143±1448C 3toluene);
3Found: C, 74.4; H, 5.2; N, 6.0. C28H24N2O4 requires C,
74.3; H, 5.3; N, 6.2%); nmax 3CH2Cl2) 1724, 1282, 1246,
1121 cm21; dH 3250 MHz; CDCl3) 7.96 34H, s, terephtha-
loyl H), 7.67 32H, dd, Jˆ6.9, 1.1 Hz, aryl H), 7.43 32H, dd,
Jˆ6.8, 0.8 Hz, aryl H), 7.28±7.22 32H, m, aryl H), 7.19±
7.13 34H, m, aryl H), 6.56 32H, d, Jˆ3.3 Hz, Ar-3H), 4.65
34H, t, Jˆ5.1 Hz, CH2CH2), 4.53 34H, t, Jˆ5.2 Hz,
CH2CH2); dC 3100 MHz; CDCl3) 165.8 3CvO), 136.6,
134.0, 130.1 3terephthaloyl CH), 129.2, 128.3 3CH), 122.3
3CH), 121.6 3CH), 120.2 3CH), 109.6 3CH), 102.6 3CH),
64.5 3OCH2), 45.4 3NCH2); m/z 3EI) 452 3M1, 29%),143
3100), 51 318).
solution of the alcohol 21 3284 mg, 1.34 mmol) and triethyl-
amine 30.75 mL) in dichloromethane 35 mL). The reaction
was stirred overnight. The solvent was removed under
reduced pressure. Column chromatography 3dichloro-
methane) yielded the title compound 3383 mg, 79%) as a
yellow solid, mp 173±1748C 3toluene); 3Found: C, 70.1; H,
4.4; N, 7.8. C21H16N2O4 requires C, 70.0; H, 4.5; N, 7.8%);
n
max 3CH2Cl2) 1728, 1530, 1351, 1273 cm21; dH 3250 MHz;
CDCl3) 9.14 32H, d, Jˆ8.8 Hz, benzoyl H), 9.11 32H, d,
Jˆ7.7 Hz, aryl H), 8.88 32H, d, Jˆ8.8 Hz, benzoyl H),
8.46 34H, d, Jˆ7.7 Hz, aryl H), 8.29±8.23 32H, m, aryl
H), 4.75 34H, s, CH2CH2); dC 3100 MHz; CDCl3) 164.9
3CvO), 150.9 3C), 140.8 3C), 135.2 3C), 131.1 3CH),
126.3 3CH), 123.8 3CH), 123.6 3C), 121.0 3CH), 119.9
3CH), 108.9 3CH), 63.9 3OCH2), 41.9 3NCH2); m/z 3EI)
193 324%), 180 3100), 152 314).
4.1.22. 2-/Carbazol-9-yl)ethyl benzenesulfonate 23.
Triethylamine 31.0 mL, 7.2 mmol) was added to a solution
of the alcohol 21 3378 mg, 1.79 mmol) and benzenesulfonyl
chloride 30.46 mL, 3.6 mmol) in dichloromethane 35 mL)
under nitrogen. The reaction was stirred overnight. The
solvent was removed under reduced pressure. Column
chromatography 31:1 dichloromethane±light petroleum,
then dichloromethane) yielded the title compound
3590 mg, 94%) as a colourless solid, mp 71±728C;
3Found: C, 68.2; H, 4.6; N, 3.8. C20H17NO3S requires C,
68.4; H, 4.9; N, 4.0%); nmax 3CH2Cl2) 1598, 1486, 1460,
1365, 1188, 917 cm21; dH 3250 MHz; CDCl3) 8.02 32H, d,
Jˆ7.8 Hz, aryl H), 7.45±7.39 34H, m, aryl H), 7.36±7.31
32H, m, aryl H), 7.27±7.20 33H, m, aryl H), 7.17±7.11 32H,
m, aryl H), 4.56 32H, t, Jˆ5.6 Hz, CH2CH2), 4.43 32H, t,
Jˆ5.6 Hz, CH2CH2); dC 3100 MHz; CDCl3) 140.4, 135.4,
133.8 3CH), 129.2 3CH), 127.6 3CH), 126.3 3CH), 123.5,
120.7 3CH), 119.9 3CH), 108.8 3CH), 67.8 3OCH2), 42.2
3NCH2); m/z 3EI) 351 3M1, 17%), 180 372), 130 313), 91
3100).
4.1.19. 2-/Carbazol-9-yl)ethanol 21. Carbazole 31.67 g,
10.0 mmol) was added to a suspension of potassium
hydroxide 32.24 g, 40.0 mmol) in DMSO 320 mL) under
an atmosphere of nitrogen. The mixture was stirred for 1 h,
then 2-chloroethanol 30.74 mL, 11.0 mmol) was added with
external cooling and the mixture stirred overnight. Water
320 mL) was added and the mixture extracted with dichloro-
methane 34£100 mL). The combined organics were then
washed with water 32£100 mL), brine 34£100 mL) and
then dried 3MgSO4). The solvent was removed under
reduced pressure. Column chromatography 399:1 dichloro-
methane±ether) yielded the title compound 31.21 g, 57%) as
a colourless solid, mp 93±948C 3lit.,16 mp 83±83.58C); nmax
3CH2Cl2) 3612, 1598, 1485, 1326, 912 cm21; dH 3250 MHz;
CDCl3) 8.14 32H, dd, Jˆ7.8, 0.8 Hz, aryl H), 7.53 32H, dt,
Jˆ7.6, 0.8 Hz, aryl H), 7.36±7.30 34H, m, aryl H), 4.13 32H,
t, Jˆ5.3 Hz, NCH2), 3.60 32H, t, Jˆ5.3 Hz, OCH2), 2.45
31H, br s, OH); dC 362.9 MHz; CDCl3) 140.7 3C), 125.8
3CH), 122.9 3C), 120.4 3CH), 119.2 3CH), 109.0 3CH),
60.9 3OCH2), 45.2 3NCH2).
4.1.23. 1,4-Di[/indol-5-yloxy)methyl]benzene 24. a,a0-Di-
bromo-p-xylene 3245 mg, 0.93 mmol) was added to a
solution of potassium carbonate 32.31 g, 16.7 mmol) and
5-hydroxyindole 3247 mg, 1.86 mmol) in acetone 310 mL).
The mixture was heated under re¯ux for 16 h. The mixture
was ®ltered and the solid washed with acetone. The solvent
was removed under reduced pressure. Column chroma-
tography 3dichloromethane) gave the title compound
3196 mg, 29%) as a colourless solid, mp 220±2228C;
3Found: M1, 368.1527. C24H20N2O2 requires 368.1525);
nmax 3CH2Cl2) 3686, 2927, 1455, 1151 cm21; dH 3250
MHz; d6DMSO) 10.91 32H, br s, NH), 7.48 34H, s, xylyl
H), 7.31±7.28 34H, m, aryl H), 7.13 32H, d, Jˆ2.1 Hz,
Ar-2H), 6.82 32H, dd, Jˆ8.8, 2.3 Hz, Ar-6H), 6.33 32H,
d, Jˆ1.9 Hz, Ar-3H), 5.10 34H, s, OCH2); dC 362.9 MHz;
d6DMSO) 157.4 3C), 142.3 3C), 136.3 3C), 133.1 3C), 132.7
3CH), 131.0 3CH), 117.1 3CH), 116.9 3CH), 108.5 3CH),
106.0 3CH), 74.7 3OCH2); m/z 3EI) 368 3M1, 20%), 236
334), 155 337), 132 3100), 104 355).
4.1.20. 2-/Carbazol-9-yl)ethyl benzoate 22a. Triethyl-
amine 30.2 mL, 1.4 mmol) was added to a solution of the
alcohol 21 3232 mg, 1.1 mmol) and benzoyl chloride
30.19 mL, 1.65 mmol) in dichloromethane 34 mL). The
mixture was stirred overnight. The solvent was removed
under reduced pressure. Column chromatography 3dichloro-
methane) yielded the title compound 3222 mg, 64%) as a
colourless solid, mp 147±1488C 3toluene) 3lit.,16 mp
142±1438C); 3Found: C, 79.9; H, 5.3; N, 4.2. C21H17NO2
requires C, 80.0; H, 5.4; N, 4.4%); nmax 3CH2Cl2) 3070,
1719, 1465, 1273 cm21; dH 3250 MHz; CDCl3) 8.12 32H,
d, Jˆ7.7 Hz, aryl H), 7.84 32H, dd, Jˆ7.7, 1.3 Hz, aryl H),
7.53±7.44 35H, m, benzoyl H), 7.36 32H, t, Jˆ7.6 Hz, aryl
H), 7.26 32H, t, Jˆ7.7 Hz, aryl H), 4.72 34H, s, CH2CH2); dC
3100 MHz; CDCl3) 166.5 3CvO), 140.5 3C), 133.1 3CH),
129.7 3CH), 129.6 3C), 128.3 3CH), 125.8 3CH), 123.1 3C),
120.5 3CH), 119.3 3CH), 108.7 3CH), 62.7 3OCH2), 41.8
3NCH2).
4.1.24. 4-[/Carbazol-9-yl)methyl]benzyl bromide 25. A
solution of carbazole 30.50 g, 3.0 mmol) and DMF 30.46
mL, 6.0 mmol) in THF 310 mL) was added to sodium
hydride 30.18 g, 7.5 mmol) under nitrogen. The reaction was
stirred for 0.25 h after which time a,a0-dibromo-p-xylene
4.1.21. 2-/Carbazol-9-yl)ethyl 4-nitrobenzoate 22b. 4-Nitro-
benzoyl chloride 3300 mg, 1.62 mmol) was added to a

J. Bloxham et al. / Tetrahedron 58 32002) 3709±3720
3719
Table 1.
Crystal data
4
6
8
Empirical formula
Formula weight
C32H24N2´1/23C3H6O)
465.59
C32H24N2
436.55
C24H20N2
336.44
Crystal dimensions 3mm)
Crystal system
Lattice parameters
0.12£0.12£0.30
0.20£0.30£0.60
0.33£0.33£0.40
Monoclinic
Ê
Monoclinic
Ê
Triclinic
Ê
Ê
Ê
Ê
Ê
aˆ14.993 32) A, bˆ16.665 31) A,
aˆ8.722 34) A, bˆ14.304 33) A,
aˆ10.489 32) A, bˆ11.619 32) A, cˆ8.190 32) A,
Ê
Ê
cˆ22.534 31) A, bˆ101.801 37)8,
cˆ9.450 33) A, bˆ104.31 33)8,
aˆ95.51 32)8, bˆ93.73 32)8, gˆ112.65 31)8,
Ê 3
Ê 3
Ê 3
Vˆ5511.3 38) A
Vˆ1142.5 37) A
Vˆ911.2 33) A
Space group
Z value
P21/n 3#14)
8
1.122
P21/c 3#14)
2
1.269
P1 3#2)
2
1.226
Dcalc 3g/cm3)
m 3CuK a) 3cm21
Re¯ections
)
5.12
8855
5.32
1917
5.19
2892
8520 unique 3Rintˆ0.135)
Obs. with I.2s3I) 2613
0.105; 0.097
1789 unique 3Rintˆ0.045)
Obs. with I.3s3I) 1426
0.052; 0.043
2718 unique 3Rintˆ0.139)
Obs. with I.3s3I) 2146
0.049; 0.040
R; Rw
CCDC deposition no.
180436
180437
180438
10
11
12
Empirical formula
Formula weight
C24H20N2
336.44
C21H22N2
302.42
C24H18N4O4
426.43
Crystal dimensions 3mm3)
Crystal system
Lattice parameters
0.30£0.30£0.50
0.15£0.21£0.31
0.18£0.18£0.78
Orthorhombic
Monoclinic
Monoclinic
Ê
Ê
Ê
Ê
Ê 3
Ê
Ê
Ê
Ê 3
Ê
aˆ10.085 34) A, bˆ27.318 36) A,
aˆ10.253 35) A, bˆ8.675 38) A,
aˆ7.291 32) A, bˆ14.261 34) A, cˆ9.694 31) A,
Ê
Ê 3
cˆ6.567 33) A, Vˆ1809 31) A
cˆ19.829 33) A, bˆ103.34 32)8,
bˆ92.37 32)8, Vˆ1007.1 34) A
Vˆ1715 31) A
Space group
Z value
P212121 3#19)
4
1.235
5.23
1621
P21/c 3#14)
4
1.171
P21/a 3#2)
2
1.406
7.68
1701
Dcalc 3g/cm3)
m 3CuK a) 3cm21
Re¯ections
)
4.93
2933
2762 unique 3Rintˆ0.128)
Obs. with I.3s3I) 1345
0.062; 0.040
1568 unique 3Rintˆ0.385)
Obs. with I.3s3I) 988
0.055; 0.038
R; Rw
CCDC deposition no.
0.043; 0.044
180439
180440
180441
13
16
18b
Empirical formula
Formula weight
C26H24N2O2
396.49
C28H21N3O2
431.49
C17H14N2O4
310.31
Crystal dimensions 3mm3)
Crystal system
Lattice parameters
0.21£0.31£0.63
0.21£0.22£0.31
0.24£0.24£0.15
Monoclinic
Monoclinic
Monoclinic
Ê
Ê
Ê
Ê
Ê
Ê
Ê 3
Ê
aˆ8.034 31) A, bˆ7.698 32) A,
aˆ9.453 31) A, bˆ16.305 32) A,
aˆ9.6734 39) A, bˆ8.2735 39) A, cˆ18.7943 36)A,
Ê
Ê 3
Ê
Ê 3
cˆ16.7098 39) A, bˆ91.075 37)8,
cˆ14.413 32) A, bˆ103.11 31)8,
bˆ93.732 35)8, Vˆ1501.0 32) A
Vˆ1033.3 33) A
Vˆ2163.7 35) A
Space group
Z value
P21/n 3#14)
2
1.274
P21/a 3#14)
4
1.324
P21/n 3#14)
4
1.373
8.28
2574
Dcalc 3g/cm3)
m 3CuK a) 3cm21
Re¯ections
)
6.04
1811
6.39
4498
1678 unique 3Rintˆ0.154)
Obs. with I.2s3I) 1328
0.056; 0.054
3361 unique 3Rintˆ0.135)
Obs. with I.3s3I) 1475
0.037; 0.033
2415 unique 3Rintˆ0.030)
Obs. with I.2s3I) 1402
0.041; 0.031
R; Rw
CCDC deposition no.
180442
180443
180444
20
22a
22b
Empirical formula
Formula weight
C28H24N2O4
452.51
C21H17NO2
315.37
C21H16N2O4
360.37
Crystal dimensions 3mm3)
Crystal system
Lattice parameters
0.10£0.10£0.25
0.12£0.21£0.37
0.03£0.10£0.20
Monoclinic
Monoclinic
Monoclinic
Ê
Ê
Ê
Ê
Ê
Ê
Ê 3
Ê
aˆ17.81 31) A, bˆ8.233 36) A,
aˆ12.397 34) A, bˆ24.002 37) A,
aˆ18.651 32) A, bˆ8.453 31) A, cˆ22.294 32) A,
Ê
Ê
cˆ17.854 37) A, bˆ118.02 33)8,
cˆ5.461 34) A, bˆ95.13 34)8,
bˆ93.082 39)8, Vˆ3509.9 38) A
Ê 3
Ê 3
Vˆ2311 32) A
Vˆ1618 31) A
Space group
Z value
P21/n 3#14)
4
1.300
P21/n 3#14)
4
1.294
P21/c 3#14)
8
1.364
7.90
5833
Dcalc 3g/cm3)
m 3CuK a) 3cm21
Re¯ections
)
7.10
3853
6.25
2614
3721 unique 3Rintˆ0.303)
Obs. with I.3s3I) 879
0.260; 0.232
2494 unique 3Rintˆ0.071)
Obs. With I.3s3I) 1437
0.036; 0.025
5639 unique 3Rintˆ0.064)
Obs. with I.2s3I) 1436
0.040; 028
R; Rw
CCDC deposition no.
180445
180446
180447

3720
J. Bloxham et al. / Tetrahedron 58 32002) 3709±3720
31.06 g, 4.0 mmol) was added. The reaction was heated to
508C for 3 h. The solvent was removed under reduced
pressure. Column chromatography 33:10 dichloromethane±
light petroleum) yielded the title compound 3397 mg, 38%)
as a colourless solid, mp 135±1368C; 3Found: M1,
349.0466. C20H1679BrN requires 349.0467); nmax 3CH2Cl2)
1598, 1486, 1461, 1326, 1211 cm21; dH 3250 MHz; CDCl3)
8.15 32H, d, Jˆ7.7 Hz, aryl H), 7.48±7.42 32H, m, aryl H),
7.37±7.25 36H, m, aryl H), 7.12 32H, d, Jˆ8.0 Hz, aryl H),
5.52 32H, s, NCH2), 4.44 32H, s, CH2Br); dC 362.9 MHz;
CDCl3) 140.6 3C), 137.6 3C), 137.1 3C), 129.5 3CH), 126.9
3CH), 126.0 3CH), 123.1, 120.5 3CH), 119.4 3CH), 108.9
3CH), 46.3 3NCH2), 33.1 3CH2Br); m/z 3EI) 351/349 3M1,
100%), 270 341), 183 339), 166 363), 104 384).
Crystallographic Data Centre, 12 Union Road, Cambridge,
CB2 1EZ, UK. The coordinates are under the deposition
numbers 180436±180447 as indicated in the table.
Acknowledgements
We thank the EPSRC for a studentship 3to J. B.), and the
EPSRC Mass Spectrometry Service at Swansea for mass
spectra.
References
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4.1.25. 1,4-{[1-/carbazol-9-yl)methyl]benzylindol-5-yloxy-
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4.2. Crystallography
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