Pyrrolo-annelated tetrathiafulvalenes: The parent systems

Article abstract of DOI:10.1021/jo000742a

The synthesis of a number pyrrolo-annelated tetrathiafulvalenes, including the parent bis(pyrrolo-[3,4-d])tetrathiafulvalene (7) is decribed. Starting from readily available 4,5-bis(bromomethyl)-1,3-dithiole-2-thione (14) and sodium tosylamide, the parent

Full text of DOI:10.1021/jo000742a

5794
J . Org. Chem. 2000, 65, 5794-5805
P yr r olo-An n ela ted Tetr a th ia fu lva len es: Th e P a r en t System s
J an Oskar J eppesen,† Kazuo Takimiya,†,‡ Frank J ensen,† Thomas Brimert,† Kent Nielsen,†
Niels Thorup,§ and J an Becher*,†
Department of Chemistry, SDU, Odense University, Campusvej 55, DK-5230 Odense M, Denmark, and
Department of Chemistry, The Technical University of Denmark, DK-2800 Lyngby, Denmark
jbe@chem.sdu.dk
Received May 15, 2000
The synthesis of a number pyrrolo-annelated tetrathiafulvalenes, including the parent bis(pyrrolo-
[3,4-d])tetrathiafulvalene (7) is decribed. Starting from readily available 4,5-bis(bromomethyl)-1,3-
dithiole-2-thione (14) and sodium tosylamide, the parent 7 and the asymmetric monopyrrolo
tetrathiafulvalenes 23a ,b were prepared in good yields via a nonclassical and simple pyrrole
synthesis. Furthermore, a series of asymmetrical N-alkylated monopyrrolo/monodihydropyrro-
lotetrathiafulvalenes was prepared starting from primary amines and 14. A detailed study of the
fundamental redox behavior of this class of heterocycles is reported. NMR spectroscopy, cyclic
voltammetry, and PM3 MO calculations revealed that the pyrrolo-annelated tetrathiafulvalenes
have highly extended π-surfaces. The X-ray crystallographic analyses of the monopyrrolo tetrathia-
fulvalenes 22b and 24b, together with preliminary formation of a charge-transfer complex between
the parent donor 7 and TCNQ, are also reported.
In tr od u ction
The chemistry of tetrathiafulvalene (TTF, 1) and its
derivatives has been intensively studied since the dis-
covery of the first metallic charge-transfer TTF complex.1
The TTF skeleton has been extensively modified over the
past two decades to enhance dimensionality in the related
charge-transfer salts.2 Among those modifications, the
heterocyclic-fused TTF donor, bis(ethylenedithio)tetra-
thiafulvalene (BEDT-TTF, 2), has given rise to more
superconducting salts than any other TTF derivative,
with κ-(BEDT-TTF)2-Cu[N(CN)2]Br as the current record
holder.3
A variety of donor molecules have been synthesized in
which the TTF core is annelated to benzenoid 3,4 furan,5
thiophene,6 or selenophene7 units 4 (Figure 1); all of these
compounds have oxidation potentials appreciably higher
F igu r e 1.
* To whom correspondence should be addressed. Fax: Int. code +
45(66)158780.
† Odense University.
than that of TTF (1) itself. Furthermore, there has been
an increasing interest in incorporating tetrathiaful-
valenes into macrocyclic and supramolecular structures.2d,8
Cava and co-workers have recently presented a detailed
study of bis(2,5-dimethylpyrrolo[3,4-d])tetrathiafulvalene
(5), the related monopyrrolo-annelated tetrathiafulvalene
6, and their N-alkylated derivatives (Figure 1).9 The
synthesis of 5 involves classical pyrrole chemistry, build-
ing up the 1,3-dithiole-2-thione moiety from a 2,5-
dimethylpyrrole core.10 Annelation of TTF to two electron-
‡ Current address: Department of Applied Chemistry, Faculty of
Engineering, Hiroshima University, Kagamiyama 1-4-1, Higashi-
Hiroshima 739-8527, J apan.
§ The Technical University of Denmark.
(1) Ferraris, J . P.; Cowan, D. O.; Walatka, V.; Perlstein, J . H. J .
Am. Chem. Soc. 1973, 95, 948-949.
(2) (a) Otsubo, T.; Aso, Y.; Takimiya, K. Adv. Mater. 1996, 8, 203-
211. (b) Bryce, M. R. J . Mater. Chem. 1995, 5, 1481-1496. (c) Garin,
J . Adv. Heterocycl. Chem. 1995, 62, 249-304. (d) Adam, M.; Mu¨llen,
K. Adv. Mater. 1994, 6, 439-459. (e) Schukat, G.; Fangha¨nel, E. Sulfur
Rep. 1996, 18, 1-294.
(3) Kini, A. M.; Geiser, U.; Wang, H. H.; Carlson, K. D.; Williams,
J . M.; Kwok, W. K.; Vandervoort, K. G.; Thompson, J . E.; Stupka, D.
L.; J ung, D.; Whangbo, M.-H. Inorg. Chem. 1990, 29, 2555-2557.
(4) Lerstrup, K.; Talham, D.; Bloch, A.; Cowan, D. J . Chem. Soc.,
Chem. Commun. 1982, 336-337.
(8) (a) J ørgensen, T.; Hansen, T. K.; Becher, J . Chem. Soc. Rev. 1994,
23, 41-51. (b) Becher, J .; Li, Z.-T.; Blanchard, P.; Svenstrup, N.; Lau,
J .; Nielsen, M. B.; Leriche, P. Pure Appl. Chem. 1997, 69, 465-470.
(9) (a) Zong, K.; Chen, W.; Cava, M. P.; Rogers, R. D. J . Org. Chem.
1996, 61, 8117-8124. (b) Chen, W.; Cava, M. P.; Takassi, M. A.;
Metzger, R. M. J . Am. Chem. Soc. 1988, 110, 7903-7904. (c) Zong, K.;
Cava, M. P. J . Org. Chem. 1997, 62, 1903-1905.
(10) The two methyl groups are mandatory in this synthesis because
the first step is an electrophilic thiocyanation at the â-positions and
they serve to block the more reactive R-positions.
(5) Siquot, Y.; Fre`re, P.; Nozdryn, T.; Cousseau, J .; Salle´, M.;
J ubault, M.; Orduna, J .; Gar´ın, J .; Gorgues, A. Tetrahedron Lett. 1997,
38, 1919-1922.
(6) Shu, P.; Chiang, L.; Emge, T.; Holt, D.; Kistenmacher, T.; Lee,
M.; Stokes, J .; Poehler, T.; Bloch, A.; Cowan, D. J . Chem. Soc., Chem.
Commun. 1981, 920-921.
(7) Ketcham, R.; Ho¨rnfeldt, A.-B.; Gronowitch, S. J . Org. Chem.
1984, 49, 1117-1119.
10.1021/jo000742a CCC: $19.00 © 2000 American Chemical Society
Published on Web 08/17/2000

Pyrrolo-Annelated Tetrathiafulvalenes
J . Org. Chem., Vol. 65, No. 18, 2000 5795
Sch em e 1
rich 2,5-dimethylpyrrole rings produces a donor system
with a lower oxidation potential than that of the parent
TTF (1), and this in connection with the higher symmetry
suggests 5 to be a useful building block in supramolecular
chemistry, devoid of cis/trans isomerism as in the simple
TTFs.11 However, the four methyl groups in 5, acting as
protecting groups during the synthesis, block the R-posi-
tions in the pyrrole units, excluding the possibility for
further C-functionalization in addition to N-alkylations.
Furthermore, steric hindrance can be expected from the
methyl groups, when 5 is incorporated in macrocyclic
systems.
F igu r e 2.
the ring closure reaction. Second, it works as an excellent
protecting group for the pyrrole nitrogen during the
harsh triethyl phosphite coupling reaction. Finally, the
tosyl groups can be removed almost quantitatively under
mild conditions from the aromatic pyrrole ring.
In this context, the parent bis(pyrrolo[3,4-d])tetra-
thiafulvalene (7) appeared to be interesting (Figure 1),
and we present here a straightforward route to 7 and
the related monopyrrolo annelated TTFs 8, through a
nonclassical pyrrole synthesis.12,13
The construction of R,R′-unsubstituted N-tosyl-2,5-
dihydropyrrolo annelated heterocycles 10 from tosyl-
amide/sodium tosylamide (Scheme 1) and unsaturated
1,2-bishalomethyl precursors 9 has been sporadically
described in the literature.14 However, to the best of our
knowledge subsequent oxidations to the corresponding
N-tosylpyrroles 11 and complete detosylation to give R,R′-
unsubstituted pyrroles 12 have apparently not been
reported.15
In our approach, the pyrrole ring is constructed in two
steps from a 1,3-dithiole-2-thione core bearing two vicinal
bromomethyl groups. The first step is a ring closure
reaction with sodium tosylamide followed by oxidation
of the annelated dihydropyrrole ring with 2,3-dichloro-
5,6-dicyano-1,4-benzoquinone (DDQ) to give the N-tosyl-
protected pyrrole. The tosyl group plays a triple role
during this synthesis. First, it activates the nitrogen in
We have previously demonstrated that the cyanoethyl
group works as an excellent protecting group for 1,3-
dithiole-2-chalcogenone and tetrathiafulvalene thiolates,
and shown that selective and stepwise deprotection of
the cyanoethyl thiolate protecting groups is possible, by
treatment with 1 equiv of cesium hydroxide monohy-
drate.16 Although the simple S-alkyl derivatives of 6a
recently have been reported,9c similar cross-couplings of
4,5-bis(2-cyanoethylthio)-1,3-dithiole-2-chalcogenones with
5-tert-butoxycarbonyl-4,6-dimethyl-(1,3)-dithiolo-[4,5-c]-
pyrrole-2-chalcogenones to give 6b were unsuccessful
(Figure 2).17
These results encouraged us to synthesize 22c, and we
describe here the potential of 22c as a promising building
block for macrocyclic and supramolecular chemistry.
To study the difference between annelation of a dihy-
dropyrrole- and a pyrrole unit to tetrathiafulvalene, a
series of asymmetrical N-alkylated monopyrrolo/monodi-
hydropyrrolotetrathiafulvalenes was prepared starting
from primary amines and 14.
The π-donor ability of the new systems was investi-
gated by cyclic voltammetry and theoretical methods
together with preliminary formation of a tetracyanoquin-
odimethane (TCNQ) complex. We also report the X-ray
crystal structures of the monopyrrolo-TTFs 22b and 24b.
(11) (a) Simonsen, K. B.; Zong, K.; Rogers, R. D.; Cava, M. P.; Becher,
J . J . Org. Chem. 1997, 62, 679-686. (b) Lau, J .; Nielsen, M. B.; Thorup,
N.; Cava, M. P.; Becher, J . Eur. J . Org. Chem. 1999, 3335-3341.
(12) For a comprehensive review on pyrrole synthesis, see: Bird,
C. W. Comprehensive Heterocyclic Chemistry II, Vol. 2; Katritzky, A.
R., Rees, C. W., Scriven, E. F. V., Eds.; Pergamon: Oxford, 1996; pp
1-257.
(13) A preliminary account on the synthesis of compounds 7 and
23a has recently been published, see: J eppesen, J . O.; Takimiya, K.;
J ensen, F.; Becher, J . Org. Lett. 1999, 1, 1291-1294.
Resu lts a n d Discu ssion
Syn th esis of (1,3)-Dith iolo[4,5-c]p yr r ole-2-ch a lco-
gen on es. The starting material in our synthesis is the
(14) (a) Scheffer, J . R.; Ihmels, H. Liebigs Ann./ Recl. 1997, 1925-
1929. (b) Kim, W.-J .; Kim, B.-J .; Lee, T.-S.; Nam, K.-S.; Kim, K.-J .
Heterocycles 1995, 41, 1389-1397. (c) J endralla, H.; Fisher, G. Ibid.
1995, 41, 1291-1298. (d) Bottino, F.; Grazia, M. D.; Finocchiaro, P.;
Fronczek, F. R.; Mamo, A.; Pappalardo, S. J . Org. Chem. 1988, 53,
3521-3529. (e) Stapler, J . T.; Bornstein, J . J . Heterocycl. Chem. 1973,
10, 983-988.
(15) The dehydrogenation of N-alkyl/arylsulfonyl-2,5-dihydropyr-
roles with different oxidation agents has been described, see: (a)
Suzuki, T.; Ohyabu, H.; Takayama, H. Heterocycles 1997, 46, 199-
202. (b) Xu, Z.; Lu, X. Tetrahedron Lett. 1997, 38, 3461-3464. (c) Ando,
K.; Kankake, M.; Suzuki, T.; Takayama, H. Tetrahedron 1995, 51,
129-138. (d) Suzuki, T.; Takayama, H. J . Chem. Soc., Chem. Commun.
1995, 807-808. (e) Ando, K.; Kankake, M.; Suzuki, T.; Takayama, H.
J . Chem. Soc., Chem. Commun. 1992, 1100-1102.
(16) (a) Svenstrup; N.; Rasmussen, K. M.; Hansen, T. K.; Becher,
J . Synthesis 1994, 809-812. (b) Simonsen, K. B.; Svenstrup, N.; Lau,
J .; Simonsen, O.; Mørk, P.; Kristensen, G. J .; Becher, J . Synthesis 1995,
407-418. (c) Simonsen, K. B.; Becher, J . Synlett 1997, 1211-1220.
(17) Cava, M. P.; Becher, J . Unpublished results.
(18) J eppesen, J . O.; Takimiya, K.; Thorup, N.; Becher, J . Synthesis
1999, 803-810.
(19) Recently an experimental procedure using CBr4/PPh3 has been
reported by Mu¨llen and co-workers, see: Skabara, P. J .; Mu¨llen, K.;
Bryce, M. R.; Howard, J . A. K.; Batsanov, A. S. J . Mater. Chem. 1998,
8, 1719-1724.
(20) The use of PBr3 has been reported in a communication from
Gorgues and co-workers, see: Durand, C.; Hudhomme, P.; Duguay,
G.; J ubault, M.; Gorgues, A. Chem. Commun. 1998, 361-362.

5796 J . Org. Chem., Vol. 65, No. 18, 2000
J eppesen et al.
Sch em e 2
Sch em e 3
diol 13,18 which was dibrominated with phosphorus
tribromide (PBr3) to give dibromide 14.19,20 Cyclization
was performed by treatment of 14 with 2 equiv sodium
tosylamide affording the dihydropyrrolo compound 15a
in 89% yield (Scheme 2).
Deprotection of the tosyl group in 22a ,b with sodium
methoxide in a 1:1 mixture of THF-MeOH afforded the
asymmetrical monopyrrolo-TTFs 23a ,b in high yields
(Scheme 4). Alkylation of 23a proceeded smoothly to give
the N-alkylated derivatives 24a -c.
Transchalcogenation of thione 15a with mercuric
acetate in a mixture of chloroform and glacial acetic acid
gave ketone 15b in 99% yield. Dehydrogenation of the
dihydropyrroles 15a ,b using 2 equiv of DDQ in chlo-
robenzene afforded the N-tosylated (1,3)-dithiolo[4,5-c]-
pyrrole-2-chalcogenones 16a ,b in 75% and 95% yields,
respectively. Detosylation of 16a was carried out by
treatment of 16a with sodium methoxide in a 1:1 mixture
of THF-MeOH, affording the pyrrole 17 in 84% yield.21
Syn th esis of Bis(pyr r olo[3,4-d])tetr ath iafu lvalen es.
Self-coupling of the ketone 16b to form the TTF 18 using
triethyl phosphite proceeded in 84% yield (Scheme 3).
Removal of the tosyl protecting groups of 18 was
carried out by refluxing a suspension of 18 and sodium
methoxide in a 1:1 mixture of THF-MeOH, affording the
novel bis(pyrrolo)-TTF 7 in quantitative yield. Finally, 7
was dialkylated to give the N,N′-dialkyl derivatives 19a ,b
in 82-83% yields (Scheme 3). Treatment of the ketone
15b with triethyl phosphite gave bis(2,5-dihydro-N-
tosylpyrrolo[3,4-d])tetrathiafulvalene (20) in 35% yield
as a very insoluble solid (Scheme 3). Although several
attempts were performed to remove the tosyl groups in
20, we never succeeded in obtaining bis(2,5-dihydro[3,4-
d])tetrathiafulvalene (21) probably on account of the high
chemical stability of the sulfamide bonds and the low
solubility of 20.
P oten tia l of 22c a s a Bu ild in g Block for Su -
p r a m olecu la r Ch em istr y. To study the potential of 22c
as a building block for macrocyclic and supramolecular
chemistry, the following regioselective deprotection and
realkylation reactions were carried out. Treatment of a
THF solution of 22c with 1 equiv of cesium hydroxide
monohydrate generated the TTF-monothiolate selec-
tively, without interfering with the tosyl protecting group,
evidenced by quenching of the thiolate with iodomethane
to give the methylthio substituted TTF 25 in near
quantitative yield. Subsequently, the remaining cyano-
ethyl thiolate protecting group in 25 was deprotected
using 1 equiv of cesium hydroxide monohydrate followed
by addition of iodomethane, affording the bis(methylthio)
Sch em e 4
Syn th esis of Mon op yr r olo[3,4-d ]tetr a th ia fu l-
va len es. Cross-coupling of 16b with 2 equiv of 4,5-bis-
(methylthio)-1,3-dithiole-2-thione, 4,5-bis(pentylthio)-1,3-
dithiole-2-thione, and 4,5-bis(2-cyanoethylthio)-1,3-dithiole-
2-thione, respectively, in neat triethyl phophite afforded
the N-tosyl-protected asymmetrical monopyrrolo-TTFs
22a -c in 55-69% yields (Scheme 4).22
(21) Care must be taken during workup, especially with regard to
temperature; otherwise ring opening occurs in the 1,3-dithiole ring and
a mixture of 17 and 3,4-bis(methylthio)pyrrole is isolated.
(22) Cross-coupling of thione 16a and 2 equiv of 4,5-bis(methylthio)-
1,3-dithiol-2-one in neat triethyl phosphite afforded TTF 22a in a
considerably lower yield (26%), compared to the cross-coupling reaction
between ketone 16b and 4,5-bis(methylthio)-1,3-dithiole-2-thione.

Pyrrolo-Annelated Tetrathiafulvalenes
J . Org. Chem., Vol. 65, No. 18, 2000 5797
Sch em e 5
Sch em e 7
substituted TTF 22a in 95% yield.To obtain 22a directly
from 22c, the following reaction sequence was neces-
sary.23 A THF solution of 22c was treated with 1 equiv
of cesium hydroxide monohydrate and the resulting
monothiolate realkylated with iodomethane, whereupon
excess iodomethane was removed.24 The residue was then
treated with 1 equiv of cesium hydroxide monohydrate,
followed by addition of iodomethane, which effected the
second deprotection/realkylation sequence and afforded
22a in 93% yield (Scheme 5).
Syn th esis of Asym m etr ica l N-Alk yla ted Mon op y-
r r olo/Mon odih ydr opyr r olotetr ath iafu lvalen es. Treat-
ment of dibromide 14 with butylamine in a refluxing
mixture of THF and CH3CN, in the precence of excess
cesium carbonate, gave the N-butyldihydropyrrole 26a
in 79% yield (Scheme 6).
rosilane in the presence of imidazole, giving the silyl
protected 1,3-dithiole-2-thione 26d in 81% yield.25 The
THP protected ethanolamine was synthesized in a two-
step reaction from commercially available ethanol-
amine,26 which implies that five steps are necessary in
this approach to 26d . Instead, 26d can be synthesized
in a one-pot synthesis starting from 14 and ethanol-
amine, followed by treatment with tert-butyldiphenyl-
chlorosilane in the presence of imidazole (Scheme 6),
affording 26d in an acceptable yield. The advantage of
the second route is obvious.
Cross-coupling of the dihydropyrroles 26a ,b,d with 3
equiv of 4,5-bis(methylthio)-1,3-dithiol-2-one or 4,5-bis-
(2-cyanoethylthio)-1,3-dithiol-2-one in neat triethyl phos-
phite gave the asymmetrical N-alkyl-dihydropyrrolo-
TTFs 27a ,b,d in moderate yields (Scheme 7).
Using similar reaction conditions, 26b was obtained
in 73% yield by treatment of dibromide 14 with THP-
protected ethanolamine (Scheme 6). The THP protecting
group in 26a was removed using aqueous hydrochloric
acid, affording the alcohol 26c in almost quantitative
yield, which subsequently was protected as the tert-
butyldiphenylsilyl ether, using tert-butyldiphenylchlo-
The TTF-alcohol 28 was obtained in optimum yield by
removal of the THP protecting group in 27b using
aqueous hydrochloric acid. Deprotection of the silyl group
in 27d with tetrabutylammonium flouride (TBAF) af-
forded 28 in 54% yield after recrystallization (Scheme 7).
Oxidation of the dihydropyrroles 26a ,d with DDQ
proceeded in high yields under mild conditions affording
the corresponding pyrroles 29a ,d , which subsequently
were cross-coupled with 4,5-bis(methylthio)-1,3-dithiol-
2-one or 4,5-bis(2-cyanoethylthio)-1,3-dithiol-2-one, giving
the asymmetrical N-alkyl-monopyrrolo-TTFs 24b and 30
in 52% and 31% yields, respectively (Scheme 8).
Deprotection of the tert-butyldiphenylsilyl protecting
group in 30 with TBAF afforded the TTF-alcohol 31 in
92% yield.
Sch em e 6
E lect r och em ist r y of Com p ou n d s 7, 18, 19, a n d
22-25. Solution oxidation potentials obtained from cyclic
voltammograms (CVs) of pyrrolo-TTF π donors (D) and
(23) Treatment of 22c with 2.1 equiv of cesium hydroxide monohy-
drate dissolved in MeOH, followed by addition of excess iodomethane,
afforded only 22a in 42% yield, together with byproducts where the
tosyl group had been partially deprotected and/or the cyanoethyl
thiolate protecting groups partially deprotected.
(24) At this point it was verified by TLC and PDMS that clean
monodeprotection had taken place.
(25) Previous results have shown that a primary alcohol functional-
ity is unable to survive the standard trialkyl phosphite coupling,
whereas the tert-butyldiphenylsilyl alcohol protecting group is able to
withstand the standard coupling conditions, see: (a) Marshallsay, G.
J .; Bryce, M. R.; Cooke, G.; J ørgensen, T.; Becher, J .; Reynolds, C. D.;
Wood, S. Tetrahedron 1993, 49, 6849-6862. (b) Marshallsay, G. J ;
Hansen, T. K.; Moore, A. J .; Bryce, M. R.; Becher, J . Synthesis 1995,
926-930.
(26) Passon, M.; Antoine, M.; Chabassier, S.; Geiger, S.; Girard, P.;
Richer, D.; Lajudie, P.; Hovath, E.; Leriche, B.; Patte, S. Eur. J . Med.
Chem., Chemi Ther. 1974, 9, 591-594.

5798 J . Org. Chem., Vol. 65, No. 18, 2000
J eppesen et al.
Ta ble 2. 1H NMR Ch em ica l Sh ifts for P yr r ole r-P r oton s
a n d Selected 13C NMR Ch em ica l Sh ifts (in p p m ) for
N-Su bstitu ted Asym m etr ica l Mon op yr r olo-TTF s 22a , 23a ,
a n d 24a a
Sch em e 8
fulvene
fulvene
dithiole
pyrrole
R
CadC
CdCb
dCc-Cd
Cd
HR
Ts
H
Me
112.52
107.27
107.24
117.73
121.95
121.34
126.14
117.16
116.77
112.84
110.88
114.66
7.40
6.81
6.78
a
Spectra were recorded in DMSO-d6 (25 °C) at 300 and 75 MHz
for protons and carbons, respectively.
tetramethylated analogue 5. This effect was also observed
for 23a and its R,R′-bismethylated analogue 32 (20 mV)
on account of the electron-donating effect of the R-methyl
groups.
1
The first-half wave oxidation potential E1/2 of 7 is
1
2
higher (40 mV) than that of TTF (1), indicating that
annelation of two pyrrolo units to the TTF framework
results in a decrease of the electron-donating ability. The
N-tosylated pyrrolo-TTFs (i.e., 18 and 22a ,b) showed the
highest oxidation potentials (both E1/21 and E1/22) in both
the bis(pyrrolo)-TTF series and the monopyrrolo-TTF
series, whereas the N-alkylated pyrrolo-TTFs (i.e., 19a ,b
and 24a -c) revealed the lowest oxidation potentials (both
E1/21 and E1/22), due to the inductive effect exhibited from
the tosyl groups and alkyl groups, respectively.
Ta ble 1. Oxid a tion P oten tia ls E1/2 a n d E1/2 of
P yr r olo-TTF Der iva tives 7, 18, 19a ,b, 22a -c, 23a ,b, 24a -c,
a n d 25 Deter m in ed by Cyclic Volta m m etr ya ,b
1
2
compd
E1/2 (V)
E1/2 (V)
∆Ep (V)
TTF (1)
5
7
0.34
0.33
0.38
0.55
0.36
0.36
0.60
0.59
0.66
0.44
0.44
0.42
0.42
0.42
0.62
0.42
0.73
0.74
0.72
0.96
0.70
0.70
0.87
0.86
0.95
0.75
0.75
0.74
0.73
0.73
0.90
0.76
0.39
0.41
0.34
0.41
0.34
0.34
0.27
0.27
0.29
0.31
0.31
0.32
0.31
0.31
0.28
0.34
18c
19a
19b
22a
22b
22c
23a
23b
24a
24b
24c
25
NMR Sp ectr oscop y. An interesting feature of the
monopyrrolo-TTFs is found in their 13C chemical shifs,
1
which are summarized in Table 2 together with the H
chemical shifts.
As expected, the tosyl group has a strong influence on
the chemical shift of the pyrrole protons. The most
remarkable fact, however, is that the tosyl group is able
to shift most of the 13C resonances in 22a . Especially for
the fulvene CadC, which is located six bonds away from
the tosyl group, a significant change in the chemical shift
is observed, indicating a pronounced extension of the
π-surface in monopyrrolo-TTFs.
High est Occu p ied Molecu la r Or bita ls. To shed
more light on the extension of the π-surface in pyrrolo-
TTFs, the characters of the highest occupied molecular
orbital (HOMO) of 7 and 23a were calculated using the
semiempirical PM3 method.30 Figure 3 (top) shows the
electron distribution of 7, and it is noteworthy that
approximately 21% of the HOMO density is located on
the outer two pyrrole rings, similar to that of BEDT-TTF
(2) where the outer sulfur atoms have relatively large
HOMO densities with the same phase as the inner sulfur
atoms.31
32
a
Conditions: Ag/AgCl electrode, Pt electrode, 20 °C, Bu4NPF6
(0.1 M in CH3CN), scan rate 0.1 Vs-1, [compound] 10-3 M. The
oxidation potentials for parent TTF (1), bis(2,5-dimethylpyrrolo-
[3,4-d])tetrathiafulvalene (5),9 and 4,6-dimethyl-2-[4,5-bis(meth-
ylthio)-1,3-dithiole-2-yliden]-(1,3)-dithiolo[4,5-c]pyrrole (32) (i.e.,
R,R′-dimethyl substituted analogue of 22a )29 were measured under
identical conditions for comparison. c [18] , 10-3 M, on account
of the low solubility in CH3CN.
b
DFT calculated first oxidation potentials are summarized
in Table 1.27,28 The CVs of all compounds revealed two
pairs of reversible redox waves, indicating good stability
of the corresponding radical cation (D•+) and dication
(D2+). Compound 7 showed a higher first half-wave
1
oxidation potential E1/2 (50 mV) than its R,R′,R′′,R′′′-
(27) The first oxidation potentials were calculated from the energy
difference between D and D•+ with the B3LYP/6-31G(d) method and
the PCM solvent model, using PM3-optimized geometries.
For the asymmetrical monopyrrolo-TTF 23a , approxi-
mately 13% of the HOMO density is located on the outer
pyrrole ring (Figure 3, bottom), clearly demonstrating an
extension of the π-surface in pyrrolo-TTFs.
X-r a y Cr ysta llogr a p h y. To study the effect of N-
substitution at the bond lengths in pyrrolo-TTFs, X-ray
crystal structure determinations were performed at the
(28) Gaussian 98 (Revision A.5): Frisch, M. J .; Trucks, G. W.;
Schlegel, H. B.; Scuseria, G. E.; Robb, M. A.; Cheeseman, J . R.;
Zakrzewski, V. G.; Montgomery, J . A.; Stratmann, R. E.; Burant, J .
C.; Dapprich, S.; Millam, J . M.; Daniels, A. D.; Nudin, K. N.; Strain,
M. C.; Farkas, O.; Tomasi, J .; Barone, V.; Cossi, M.; Cammi, R.;
Mennucci, B.; Pomelli, C.; Adamo, C.; Clifford, S.; Ochterski, J .;
Petersson, G. A.; Ayala, P. Y.; Cui, Q.; Morokuma, K.; Malick, D. K.;
Rabuck, A. D.; Raghavachari, K.; Foresman, J . B.; Cioslowski, J .; Ortiz,
J . V.; Stefanov, B. B.; Liu, G.; Liashenko, A.; Piskorz, P.; Komaromi,
I.; Comperts, R.; Martin, R. L.; Fox, D. J .; Keith, T.; Al-Laham, M. A.;
Peng, C. Y.; Nanayakkara, A.; Gonzalez, C.; Challacombe, M.; Gill, P.
M. W.; J ohnson, B. G.; Chen, W.; Wong, M. W.; Andres, J . L.; Head-
Gordon, M.; Replogle, E. S.; Pople, J . A. Gaussian, Inc., Pittsburgh,
PA, 1998.
(29) Lomholt, C.; Nielsen, M. B.; Becher, J . Unpublished results.
(30) (a) Stewart, J . J . P. J . Comput. Chem. 1989, 10, 209-220. (b)
Stewart, J . J . P. J . Comput. Chem. 1989, 221-264.
(31) Mori, T.; Kobayashi, A.; Sasaki, Y.; Saito, G.; Inokuchi, H. Bull.
Chem. Soc. J pn. 1984, 57, 627-633.

Pyrrolo-Annelated Tetrathiafulvalenes
J . Org. Chem., Vol. 65, No. 18, 2000 5799
1
2
Ta ble 3. Oxid a tion P oten tia ls E1/2 a n d E1/2 of
Asym m etr ica l Mon op yr r olo/Dih yd r op yr r olo-TTF
Der iva tives 27a ,b,d , 28, 24b, 30, a n d 31 Deter m in ed by
Cyclic Volta m m etr ya
1
2
compd
E1/2 (V)
E1/2 (V)
∆Ep (V)
27a
27b
27d
28
24b
30
0.50
0.56
0.56
0.58b
0.44
0.54
0.54c
0.92
0.96
0.96
0.96b
0.87
0.95
0.92c
0.42
0.40
0.40
0.38
0.33
0.41
0.38
31
a
Conditions: Ag/AgCl electrode, Pt electrode, 20 °C, Bu4NPF6
(0.1 M in CH2Cl2), scan rate 0.1 Vs-1, [compound] 10-3 M.
Irreversible. c Quasi-reversible.
b
F igu r e 3. HOMO orbitals of 7 (top) and 23a (bottom):
lightface numbers ) HOMO electron density, boldface num-
bers ) HOMO coefficients.
electron rich aromatic pyrrole ring produces a stronger
donor system compared to annelation of a nonaromatic
dihydropyrrole system.
asymmetrical monopyrrolo-TTFs 22b and 24b.32 Single
crystals of 22b and 24b were obtained by recrystalliza-
tion from acetone/cyclohexane and dichloromethane/
hexane, respectively. The bond lengths in the structure
of 22b differ little from those of 24b. The only significant
difference is the length of the formal double bond C3-
C4 which is 1.348(4) Å in 22b, whereas the corresponding
value in 24b is 1.30(1) Å (Figure 4). This observation may
indicate a more extended π-electron system in the former
compound. This assumption is corroborated by the fact
that the pyrrolo-TTF part of 22b is close to planar as
opposed to the bent structure of 24b. The central TTF
plane (S1, S2, S5, S6, C1, and C2) in 22b makes a
dihedral angle of 2.8° with the pyrrole outer plane (S1,
S6, N1, C5, C6, C7, and C8) and a dihedral angle of 4.9°
with the outer plane (S2, S3, S4, S5, C3, and C4). The
corresponding angles in 24b are 17.6° and 19.3°, respec-
tively.
Th eor ectica l Ca lcu la tion s. The energy for removing
one electron was calculated at the B3LYP density func-
tional level with the 6-31G(d) basis set, using PM3-
optimized geometries.33 Solvent effects were modeled
with the IEFPCM method,34 which is a continuum solvent
model employing a molecular shaped cavity. As seen from
the results in Table 4 this method is capable of reproduc-
ing trends in the first oxidation potential quite well, both
between different compounds in the same solvent, and
changes between solvents.
1
Ta ble 4. Com p a r ison of Oxid a tion P oten tia ls E1/2 a n d
2
E1/2 for Selected P yr r olo/Dih yd r op yr r olo-TTF
Der iva tives in CH3CN or CH2Cl2, Resp ectively,
Deter m in ed by Cyclic Volta m m etr ya
CH3CN
CH2Cl2
1
2
1
2
E1/2
E1/2
Eox1(DFT) E1/2
E1/2
Eox1(DFT)
compd
(V)
(V)
(eV)
(V)
(V)
(eV)
19a
19b
22a
22b
22c
23a
23b
24a
24b
24c
25
0.36
0.36
0.60
0.59
0.66
0.44
0.44
0.42
0.42
0.42
0.62
0.70
0.70
0.87
0.86
0.95
0.75
0.75
0.74
0.73
0.73
0.90
4.49
0.36
0.35
0.64
0.62
0.73
0.46
0.48
0.43
0.44
0.44
0.67
0.50
0.86
0.86
1.01
1.00
1.10
0.92
0.93
0.87
0.87
0.87
1.04
0.92
4.57
4.82
4.93
4.91
4.65
5.03
4.74
F igu r e 4. Crystallographic atom numbering of 22b and 24b.
4.61
4.60
4.70
4.69
Ch ar ge-Tr an sfer Com plex. A combination of equimo-
lar amounts of the new donor 7 and TCNQ in acetonitrile
gave a crystalline charge-transfer complex, which was
shown to be a 1:1 complex by elemental analysis. The
conductivity of 7‚TCNQ on a single crystal was measured
at room temperature, using the four probe method, and
27a
28
31
0.44b 0.74b
0.50c 0.81c
0.48d 0.80
4.64
4.74
4.70
4.75
4.90
4.82
0.58c 0.96c
0.54d 0.92d
a
Conditions: Ag/AgCl electrode, Pt electrode, 20 °C, Bu4NPF6
(0.1 M in CH3CN or CH2Cl2), scan rate 0.1 Vs-1, [compound] 10-3
was relatively high, 0.02 S cm-1
.
E lect r och em ist r y of Asym m et r ica l N-Alk yla t ed
Mon op yr r olo/Mon od ih yd r op yr r olot e t r a t h ia fu l-
va len es. As expected, the dihydropyrrolo-TTFs 27a ,d
and 28 and the pyrrolo-TTFs 24b, 30, and 31 display
different physical properties. In particular with regard
to solubility and affinity toward silica gel. To shed more
light on the differences between dihydropyrrolo-TTFs and
pyrrolo-TTFs, their electrochemical properties were in-
vestigated by cyclic voltammetry. Solution oxidation
potentials obtained from cyclic voltammograms (CVs) are
summarized in Table 3.
b
M. [27a ] , 10-3 M, on account of the low solubility in CH3CN.
c Irreversible. Quasi-reversible.
d
Con clu sion s
In conclusion, we have described a short and efficient
synthetic route to the potentially useful symmetric bis-
(pyrrolo)-TTF 7 and the asymmetric monopyrrolo-TTFs
23a ,b and demonstrated that the new pyrrole synthesis
for construction of R,R′-unsubstituted pyrrolo-annelated
heterocycles is useful for 1,3-dithiole-2-thione. This route
may be extended to other fused pyrroles as well.
The pyrrolo-TTFs have lower oxidation potentials (both
E1/21 and E1/22) compared to the dihydropyrrolo-TTFs. This
indicates that annelation of tetrathiafulvalene to an
(33) (a) Becke, A. D. J . Chem. Phys. 1993, 98, 5648. (b) Lee, C.; Yang,
W.; Parr, R. G. Phys. Rev. B, 1988, 37, 785. (c) Hehre, W. J .; Ditchfield,
R.; Pople, J . A. J . Chem. Phys. 1972, 56, 2257.
(34) Cance`s, E.; Mennucci, B.; Tomasi, J . J . Chem. Phys, 1997, 107,
3032.
(32) The X-ray data and molecular structures for compounds 22b
and 24b are included as Supporting Information.

5800 J . Org. Chem., Vol. 65, No. 18, 2000
J eppesen et al.
20 min to a suspension of TsNHNa (4.00 g, 20.7 mmol) in
anhyd CH3CN (100 mL) at 80 °C. The brown reaction mixture
was stirred for further 5 min, whereupon the hot mixture was
filtered through Celite (1 cm) and the filter washed with DMF.
The filtrates were combined and allowed to cool to room
temperature giving a yellow precipitate, which was collected
by filtration and washed with CH3CN to give 0.81 g (25%) of
pure 15a as yellow needles. The mother liquid was subse-
quently concentrated in vacuo and the brown residue was
purified by column chromatography (silica gel, CH2Cl2, Rf )
0.4) to give additional 2.10 g (64%) of pure 15a as yellow
needles. Recrystallization from toluene/cyclohexane gave 15a
as fine yellow needles: mp 234 °C dec.
Furthermore, we have developed an efficient synthesis
of the asymmetric monopyrrolo-TTF 22c and demon-
strated that it is promising as a new building block for
supramolecular and macrocyclic chemistry.
The pyrrolo-annelated tetrathiafulvalenes have highly
extented π-surfaces, which strongly influence the physical
properties of this class of heteocycles in both the solid
state and in solution.
Investigations in the direction of tetrathiafulvalene-
containing polypyrroles and porphyrin35 systems are
currently in progress.
Meth od 2. A solution of 14 (4.81 g, 15.0 mmol) in anhyd
DMF (75 mL) was added in one portion to a solution of
TsNHNa (2.90 g, 15.0 mmol) in anhyd DMF (200 mL) at 80
°C, whereupon the orange brown reaction mixture was stirred
for 1 h at 80 °C. Additional TsNHNa (2.90 g, 15.0 mmol) was
added in one portion, leaving a dark brown reaction mixture.
After the mixture was stirred for 1 h at 80 °C and cooled to
room temperature, the solvent was removed in vacuo. The
brown residue was dissolved in CH2Cl2 (500 mL), washed with
H2O (3 × 200 mL). The combined aqueous phases were
extracted with CH2Cl2 (2 × 100 mL) and the combined organic
phases were dried (MgSO4). Concentration in vacuo gave a
yellow brown solid, which was suspended in CH2Cl2 (75 mL)
and purified by column chromatography (silica gel, CH2Cl2,
Rf ) 0.4) to give 3.00 g (61%) of 15a as analytically pure yellow
needles. Recrystallization from toluene/cyclohexane gave 15a
as fine yellow needles: mp 234 °C dec; 1H NMR (DMSO-d6) δ
2.40 (s, 3H), 4.47 (s, 4H), 7.46 (d, J ) 8.3 Hz, 2H), 7.74 (d, J
) 8.3 Hz, 2H); 13C NMR (DMSO-d6) δ 21.0, 53.3, 127.6, 130.3,
133.1, 136.4, 144.4, 218.7; MS (EI) m/z 329 (M+, 35), 173 (M+
- HTs, 100); IR (KBr) ν 1343 (SO2), 1158 (SO2), 1055 (CdS)
cm-1. Anal. Calcd for C12H11NO2S4: C, 43.75; H, 3.37; N, 4.25;
S, 38.92. Found: C, 43.91; H, 3.26; N, 4.24; S, 38.93.
Exp er im en ta l Section
All reactions were carried out under an atmosphere of dry
N2 unless otherwise stated. THF was distilled from Na/
benzophenone immediately prior to use; toluene was also
purified by this procedure when high purity was needed.
MeOH was distilled from Mg. DMF and CH3CN were allowed
to stand over molecular sieves (4 Å) for at least 3 days before
use. Triethyl phosphite was purified by distillation and stored
over molecular sieves (3 Å). All reagents were standard grade
and used as received, except sodium tosylamide,14d 2-(tetrahy-
dropyran-2-oxy)ethylamine,26 4,5-bis(hydroxymethyl)-1,3-dithi-
ole-2-thione (13),18 4,5-bis(methylthio)-1,3-dithiole-2-thione,16b,36
4,5-bis(2-pentylthio)-1,3-dithiole-2-thione,16b 4,5-bis(2-cyano-
ethylthio)-1,3-dithiole-2-thione,16a 4,5-bis(methylthio)-1,3-dithiol-
2-one,37 and 4,5-bis(2-cyanoethylthio)-1,3-dithiol-2-one,16a which
were prepared according to the literature.
Analytical thin layer chromatography (TLC) was performed
on Merck DC-Alufolien Kiselgel 60 F254 0.2 mm thickness
precoated TLC plates, while column chromatography was
performed using Merck Kiselgel 60 (0.040-0.063 mm, 230-
400 mesh AST0000M). Melting points (mp) are uncorrected.
1H NMR spectra were recorded at 300 and 250 MHz, respec-
tively. 13C NMR spectra were recorded at 75 or 63 MHz using
broad band decoupling. Cyclic voltammetry (CV) was carried
out using CH2Cl2 or CH3CN as solvent employing Bu4NPF6
(0.10 M) as supporting electrolyte, with a sweep rate of 0.100
V s-1. Counter and working electrodes were made of Pt, and
the reference electrode was Ag/AgCl.
4,5-Bis(br om om eth yl)-1,3-d ith iole-2-th ion e (14). A solu-
tion of 13 (4.85 g, 25.0 mmol) in THF (150 mL) was cooled on
an ice bath before phosphorus tribromide (4.7 mL, 13.6 g, 50.4
mmol) was added, and the yellow solution was stirred for 30
min at 0 °C, whereupon the reaction mixture was stirred
overnight at room temperature. The reaction mixture was
concentrated in vacuo to a yellow oil, and carbon tetrachloride
(100 mL) was added to precipitate the product, after which
the mixture was left in a freezer for 2 h. The product was
collected by filtration and washed with cold carbon tetrachlo-
ride to give 6.40 g (80%) of pure 14 as yellow needles: mp
125.5-126 °C dec (lit.19 mp 124-126 °C). The combined filtrate
was subsequently washed with 2 M HCl, saturated aqueous
NaHCO3 solution and H2O. The organic phase was dried
(MgSO4) and concentrated in vacuo to a yellow oil, which was
dissolved in CH2Cl2 (20 mL) and filtered through a short
column (4.5 cm silica gel, 10 cm Ø, CH2Cl2). The broad yellow
band (Rf ) 0.8) was collected and concentrated to give a yellow
powder, which was recrystallized from CH2Cl2/petroleum ether
(bp 60-80 °C) to give additional 0.90 g (11%) of 14 as fine
yellow needles: mp 126-126.5 °C dec; 1H NMR (CDCl3) δ 4.33
(s, 4H); 13C NMR (CDCl3) δ 20.1, 139.5, 208.3.
4,6-Dih yd r o-N-t osyl-(1,3)-d it h iolo[4,5-c]p yr r ol-2-on e
(15b). Mercuric acetate (5.49 g, 17.2 mmol) was added in one
portion to a suspension of 15a (3.00 g, 9.11 mmol) in a mixture
of CHCl3 (160 mL) and glacial acetic acid (16 mL) causing the
initially yellow solution to change to white within 2 min. The
resulting white suspension was stirred for 4 h at room
temperature, whereupon the white precipitate was filtered
using Celite (1.0 cm) and washed thoroughly with CH2Cl2. The
combined organic phase was washed with saturated aqueous
NaHCO3 solution, H2O and dried (MgSO4). Evaporation of the
solvent in vacuo gave 2.82 g (99%) of 15b as an analytically
pure off-white solid. Recrystallization from toluene/cyclohexane
gave 15b as fine off-white needles: mp 174-174.5 °C; 1H NMR
(CDCl3) δ 2.45 (s, 3H), 4.49 (s, 4H), 7.36 (d, J ) 8.2 Hz, 2H),
7.75 (d, J ) 8.2 Hz, 2H); 13C NMR (CDCl3) δ 21.5, 53.7, 123.3,
127.6, 130.2, 133.5, 144.6, 193.9; MS (EI) m/z 313 (M+, 14),
158 (M+ - Ts, 58), 157 (M+ - HTs, 100); IR (KBr) ν 1687 (Cd
O), 1343 (SO2), 1160 (SO2) cm-1. Anal. Calcd for C12H11
-
NO3S3: C, 45.99; H, 3.54; N, 4.47; S, 30.69. Found: C, 45.89;
H, 3.49; N, 4.39; S, 30.79.
Gen er a l P r oced u r e for DDQ Oxid a tion of 15a a n d 15b.
A mixture of 15a or 15b and 2.2 equiv of DDQ in chloroben-
zene was refluxed until all starting material was consumed.
After cooling to room temperature, the solvent was removed
in vacuo and the brown residue was purified by column
chromatography (silica gel, CH2Cl2/cyclohexane 1:1 or CH2Cl2)
to give 16a or 16b as analytically pure compounds.
N-Tosyl-(1,3)-d ith iolo[4,5-c]p yr r ole-2-th ion e (16a ). 15a
(0.164 g, 0.50 mmol), chlorobenzene (10 mL), and reflux for
16 h: Rf ) 0.3 (CH2Cl2/cyclohexane 1:1); yield 0.123 g (75%);
yellow needles; mp 215-215.5 °C dec (CH2Cl2/cyclohexane);
1H NMR (CDCl3) δ 2.44 (s, 3H), 7.16 (s, 2H), 7.35 (d, J ) 8.4
Hz, 2H), 7.79 (d, J ) 8.4 Hz, 2H); 13C NMR (CDCl3) δ 21.6,
110.6, 127.3, 128.8, 130.5, 135.0, 146.3, 218.8; MS (EI) m/z 327
(M+, 72), 155 (Ts+, 76), 91 (100); IR (KBr) ν 1372 (SO2), 1174
(SO2), 1049 (CdS) cm-1. Anal. Calcd for C12H9NO2S4: C, 44.02;
H, 2.77; N, 4.28; S, 39.16. Found: C, 44.16; H, 2.67; N, 4.28;
S, 39.07.
4,6-Dih yd r o-N -t osyl-(1,3)-d it h iolo[4,5-c]p yr r ole -2-
th ion e (15a ). Meth od 1. A solution of 14 (3.20 g, 10.0 mmol)
in anhyd DMF (10 mL) was added dropwise over a period of
(35) See, for example: Ramondenc, Y.; Schwenninger, R.; Phan, T.;
Gruber, K.; Kratky, C.; Kra¨utler, B. Angew. Chem., Int. Ed. Engl. 1994,
33, 889-891.
(36) Steimecke, G.; Sieler, H.-J .; Kirmse, R.; Hoyer, B. Phosphorus
Sulfur 1979, 7, 49-55.
(37) Hartke, K.; Kissel, T.; Quante, J .; Matusch, R. Chem. Ber. 1980,
113, 1898-1906.

Pyrrolo-Annelated Tetrathiafulvalenes
J . Org. Chem., Vol. 65, No. 18, 2000 5801
N-Tosyl-(1,3)-dith iolo[4,5-c]pyr r ol-2-on e (16b). 16a (2.88
g, 9.19 mmol), chlorobenzene (120 mL), and reflux for 2 h: Rf
) 0.5 (CH2Cl2); yield 2.71 g (95%); white powder; mp 178.5-
179 °C (CH2Cl2); 1H NMR (CDCl3) δ 2.43 (s, 3H), 7.22 (s, 2H),
7.34 (d, J ) 8.4 Hz, 2H), 7.78 (d, J ) 8.4 Hz, 2H); 13C NMR
(CDCl3) δ 21.6, 112.9, 119.5, 127.2, 130.4, 135.2, 146.1, 193.9;
MS (EI) m/z 311 (M+, 52), 283 (M+ - CO, 23), 155 (Ts+, 81),
Bis(N-m et h ylp yr r olo[3,4-d ])t et r a t h ia fu lva len e (19a ).
Alkylation using iodomethane (0.12 mL, 0.27 g, 1.90 mmol):
Rf ) 0.7 (CH2Cl2); yield 0.047 g (82%); yellow solid; mp 257-
258 °C dec (toluene/petroleum ether (bp 60-80 °C));1H NMR
(DMSO-d6) δ 3.60 (s, 6H), 6.75 (s, 4H); 13C NMR (DMSO-d6) δ
36.8, 114.4, 116.9, 118.9; MS (EI) m/z 310 (M+, 100). Anal.
Calcd for C12H10N2S4: C, 46.42; H, 3.25; N, 9.02; S, 41.31.
Found: C, 46.14; H, 3.39; N, 8.93; S, 41.02.
91 (100); IR (KBr) ν 1716 (CO), 1369 (SO2), 1171 (SO2) cm-1
.
Anal. Calcd for C12H9NO3S3: C, 46.29; H, 2.91; N, 4.50; S,
30.89. Found: C, 46.38; H, 2.81; N, 4.56; S, 30.85.
Bis(N-bu tylpyr r olo[3,4-d])tetr ath iafu lvalen e (19b). Alky-
lation using butyl bromide (0.61 mL of a 0.90 M solution in
DMF, 0.55 mmol): Rf ) 0.4 (CH2Cl2/cyclohexane 1:1); yield
0.060 g (83%); yellow solid; mp 190.5-191 °C (toluene/
(1,3)-Dith iolo[4,5-c]pyr r ole-2-th ion e (17). Compound 16a
(0.28 g, 0.82 mmol) was dissolved in anhyd THF-MeOH (1:1
v/v, 20 mL) and degassed (N2, 15 min) before sodium meth-
oxide (30% in MeOH, 0.80 mL, 0.23 g, 4.20 mmol) was added
in one portion. The yellow solution was stirred for 60 min at
room temperature, leaving a yellow orange solution. H2O was
added and pH adjusted (pH ) 7) by addition of 4 M HCl. The
yellow precipitate was filtered, whereupon the slight yellow
filtrate was extracted with CH2Cl2. The combined organic
phases were dried (MgSO4) and concentrated in vacuo to give
a yellow red residue. The yellow needles and the yellow red
residue were combined and purified by column chromatogra-
phy (silica gel, CH2Cl2/cyclohexane 9:1, Rf ) 0.2) to give 0.12
g (84%) of pure 17 as yellow needles. Recrystallization from
CH2Cl2/petroleum ether (bp 60-80 °C) gave 17 as fine yellow
needles: mp 178-178.5 °C. The product is unstable under
ambient conditions and darkens after a few days; 1H NMR
(DMSO-d6) δ 7.14 (d, J ) 2.6 Hz, 2H), 12.05 (bs, 1H); 13C NMR
(DMSO-d6) δ 110.9, 121.4, 220.7; MS (EI) m/z 173 (M+, 100);
IR (KBr) ν 1055 (CdS) cm-1. Anal. Calcd for C5 H3NS4: C,
34.66; H, 1.75; N, 8.08; S, 55.51. Found: C, 34.86; H, 1.93; N,
7.98; S, 55.23.
1
petroleum ether (bp 60-80 °C)); H NMR (DMSO-d6) δ 0.87
(t, J ) 7.2 Hz, 6H), 1.22 (sextet, J ) 7.2 Hz, 4H), 1.64 (quintet,
J ) 7.2 Hz, 4H), 3.84 (t, J ) 7.2 Hz, 4H), 6.81 (s, 4H); 13C
NMR (DMSO-d6) δ 13.9, 19.1, 32.9, 49.6, 113.4, 116.7, 119.1;
MS (EI) m/z 394 (M+, 100), 337 (M+ - nBu, 4). Anal. Calcd for
C
18H22N2S4: C, 54.79; H, 5.62; N, 7.10; S, 32.50. Found: C,
54.91; H, 5.66; N, 7.15; S, 32.45.
Bis(2,5-d ih yd r o-N -t osylp yr r olo[3,4-d ])t e t r a t h ia fu l-
va len e (20). A solution of 15b (0.155 g, 0.49 mmol) in distilled
P(OEt)3 was heated at 120 °C for 2 h. After cooling to room
temperature the resulting orange precipitate was collected by
filtration, washed with MeOH and dried. Recrystallization
from DMF gave 0.052 g (35%) of 20 as orange micro crystals:
mp 272 °C (dec without melting); MS (EI) m/z 594 (M+, 20),
438 (M+ - HTs, 18), 282 (M+ - 2 × HTs, 14); IR (KBr) ν 1344
(SO2), 1162 (SO2) cm-1. Anal. Calcd for C24H22N2O4S6: C, 48.46;
H, 3.73; N, 4.71. Found: C, 47.98; H, 3.46; N, 4.41.
2-[4,5-Bis(m eth ylth io)-1,3-d ith iole-2-ylid en e]-N-tosyl-
(1,3)-d ith iolo[4,5-c]-p yr r ole 22a . Meth od 1. Compound 16b
(0.49 g, 1.57 mmol) and 4,5-bis(methylthio)-1,3-dithiole-2-
thione (0.36 g, 1.59 mmol) were suspended in distilled P(OEt)3
(15 mL) and heated to 130 °C (during heating the two solids
dissolved leaving a red solution). After 5-10 min, a yellow
precipitate was formed and the suspension was stirred for
additional 20 min at 130 °C, whereupon 4,5-bis(methylthio)-
1,3-dithiole-2-thione (0.36 g, 1.59 mmol) was added in one
portion. The red reaction mixture was stirred for 3 h at 130
°C, cooled to room temperature and addition of MeOH (40 mL)
yielded a yellow solid which was filtered and washed with
MeOH. The yellow powder was purified by column chroma-
tography (silica gel, CH2Cl2/cyclohexane 1:1, Rf ) 0.3) to give
a yellow orange semisolid, which was redissolved in CH2Cl2/
MeOH (1:1 v/v, 80 mL) and concentrated to approximately half
of its volume to precipitate the product. The yellow crystals
were collected by filtration, washed with MeOH and dried in
vacuo to give 0.44 g (57%) of 22a as analytically pure yellow
needles: mp 160-160.5 °C (CH2Cl2/MeOH); 1H NMR (DMSO-
d6) δ 2.38 (s, 3H), 2.42 (s, 6H), 7.40 (s, 2H), 7.46 (d, J ) 8.4
Hz, 2H), 7.83 (d, J ) 8.4 Hz, 2H); 13C NMR (DMSO-d6) δ 18.4,
21.1, 112.5, 112.8, 117.7, 126.1, 126.2, 127.0, 130.6, 134.6,
146.0; MS (EI) m/z 489 (M+, 86), 334 (M+ - Ts, 100); IR (KBr)
ν 1373 (SO2), 1172 (SO2) cm-1. Anal. Calcd for C17H15NO2S7:
C, 41.69; H, 3.09; N, 2.86; S, 45.83. Found: C, 41.85; H, 2.93;
N, 2.90; S, 45.97.
2-[4,5-Bis(p en t ylt h io)-1,3-d it h iole-2-ylid en e]-N-t osyl-
(1,3)-d ith iolo[4,5-c]-p yr r ole 22b. Compound 16b (1.74 g,
5.59 mmol) and 4,5-bis(pentylthio)-1,3-dithiole-2-thione (1.50
g, 4.43 mmol) were suspended in distilled P(OEt)3 (20 mL) and
heated to 130 °C (during heating the two solids dissolved
leaving a red solution and after 5-10 min a yellow precipitate
was formed). Two additional portions of 4,5-bis(pentylthio)-
1,3-dithiole-2-thione (0.90 g, 2.66 mmol) were added after 10
and 20 min, respectively. The red reaction mixture was stirred
for 5 h at 130 °C and cooled to room temperature, and addition
of MeOH (150 mL) yielded a yellow solid, which was filtered
and washed with MeOH. The yellow solid was redissolved in
CH2Cl2/MeOH (1:1 v/v, 100 mL) and concentrated to ap-
proximately half of its volume to precipitate the crude product,
which was purified by column chromatography (silica gel,
toluene, Rf ) 0.5) to give 2.33 g (69%) of pure 22b as yellow
microcrystals. Recrystallization from acetone/cyclohexane gave
yellow needles of 22b suitable for X-ray analysis: mp 79-81
°C; 1H NMR (DMSO-d6) δ 0.84 (t, J ) 7.0 Hz, 6H), 1.20-1.40
Bis(N-tosylp yr r olo[3,4-d ])tetr a th ia fu lva len e (18). Com-
pound 16b (1.03 g, 3.31 mmol) was suspended in distilled
P(OEt)3 (50 mL) and the suspension was heated to 120 °C,
causing dissolution within 5 min, leaving a yellow reaction
mixture. After approximately 15 min, a yellow precipitate was
formed. The yellow suspension was stirred for 5 h at 120 °C,
cooled to room temperature and addition of MeOH (50 mL)
yielded a yellow solid which was filtered and washed with
MeOH to give 0.82 g (84%) of 18 as analytically pure yellow
needles: mp > 250 °C; 1H NMR (DMSO-d6) δ 2.38 (s, 6H),
7.38 (s, 4H), 7.45 (d, J ) 8.4 Hz, 4H), 7.81 (d, J ) 8.4 Hz, 4H);
MS (EI) m/z 590 (M+, 46), 435 (M+ - Ts, 84), 280 (M+ - 2 ×
Ts, 100); IR (KBr) ν 1369 (SO2), 1173 (SO2) cm-1. Anal. Calcd
for
C24H18N2O4S6: C, 48.79; H, 3.07; N, 4.74; S, 32.56:
Found: C, 48.64; H, 2.96; N, 4.74; S, 32.77.
Bis(p yr r olo[3,4-d ])tetr a th ia fu lva len e (7). A suspension
of 18 (0.65 g, 1.10 mmol) in anhyd THF-MeOH (1:1 v/v, 90
mL) was degassed (N2, 15 min) before sodium methoxide (30%
in MeOH, 6.3 mL, 1.8 g, 33 mmol) was added in one portion.
The yellow suspension was refluxed for 30 min, leaving a
yellow solution, and cooled to room temperature. The reaction
mixture was concentrated to approximately 30 mL, whereupon
H2O (150 mL) was added. The yellow precipitate was filtered,
washed with H2O and dried in vacuo to give 0.31 g (quant.) of
7 as an analytically pure yellow powder: mp 215-220 °C (dec
without melting). Highly purified 7 can be obtained by column
chromatography (Al2O3, deactivated with 4% H2O, THF/MeOH
50:1): 1H NMR (DMSO-d6) δ 6.78 (d, J ) 2.1 Hz, 4H), 11.08
(bs, 2H); 13C NMR (DMSO-d6) δ 110.6, 117.3, 119.5; MS (EI)
m/z 282 (M+, 100). Anal. Calcd for C10H6N2S4: C, 42.53; H,
2.14; N, 9.92; S, 45.41. Found: C, 42.47; H, 2.15; N, 9.66; S,
45.28.
Gen er a l P r oced u r e for N-Alk yla tion of 7. Compound 7
(0.052 g, 0.184 mmol) was dissolved in anhyd DMF (5 mL),
cooled to 0 °C and degassed (N2, 15 min) before the alkylating
reagent was added to the yellow solution. Hexane washed
sodium hydride (0.032 g, 1.33 mmol) was added in one portion,
whereupon the resulting orange yellow reaction mixture was
stirred for 1 h at 0 °C. Brine (20 mL) was added careful and
the yellow precipitate was filtered, washed with H2O, MeOH
and dried in vacuo. The resulting yellow solid was purified by
column chromatography (silica gel) to give 19a or 19b as
analytically pure compounds.

5802 J . Org. Chem., Vol. 65, No. 18, 2000
J eppesen et al.
(m, 8H), 1.54 (quintet, J ) 7.0 Hz, 4H), 2.37 (s, 3H), 2.82 (t, J
) 7.0 Hz, 4H), 7.33 (s, 2H), 7.41 (d, J ) 6.8 Hz, 2H), 7.79 (d,
J ) 6.8 Hz, 2H); 13C NMR (DMSO-d6) δ 13.7, 21.1, 21.6, 29.0,
30.00, 35.6, 112.5, 112.7, 117.2, 126.1, 126.8, 126.9, 130.3,
134.8, 145.7; MS (EI) m/z 601 (M+, 83), 446 (M+ - Ts, 100);
room temperature, followed by careful addition of brine (20
mL). The yellow suspension was extracted with CH2Cl2, after
which the yellow organic phase was washed with brine and
H2O. After drying (MgSO4) and evaporation of the solvent, the
resulting yellow oil was purified by column chromatography
(silica gel, CH2Cl2 or CH2Cl2/cyclohexane 1:4) to give pure
24a -c as yellow solids.
N-Meth yl-2-[4,5-bis(m eth ylth io)-1,3-dith iole-2-yliden e]-
(1,3)-d it h iolo[4,5-c]p yr r ole (24a ). Alkylation using iodo-
methane (0.06 mL, 0.14 g, 0.96 mmol): Rf ) 0.6 (CH2Cl2); yield
19.5 mg (93%); yellow orange solid; mp 101-102 °C (CH2Cl2);
1H NMR (DMSO-d6) δ 2.43 (s, 6H), 3.60 (s, 3H), 6.78 (s, 2H);
13C NMR (DMSO-d6) δ 18.4, 36.9, 107.2, 114.7, 116.8, 121.3,
126.2; MS (EI) m/z 349 (M+, 100), 334 (M+ - CH3, 21). Anal.
Calcd for C11H11NS6: C, 37.79; H, 3.17; N, 4.01. Found: C,
37.34; H, 3.28; N, 4.24
IR (KBr) ν 1372 (SO2), 1166 (SO2) cm-1. Anal. Calcd for C25H31
-
NO2S7: C, 49.88; H, 5.19; N, 2.33; S, 37.29. Found: C, 49.95;
H, 5.22; N, 2.38; S, 37.41.
2-[4,5-Bis(2-cya n oeth ylth io)-1,3-d ith iole-2-ylid en e]-N-
tosyl-(1,3)-d ith iolo[4,5-c]p yr r ole 22c. Compound 16b (3.00
g, 9.63 mmol) and 4,5-bis(2-cyanoethylthio)-1,3-dithiole-2-
thione (2.93 g, 9.63 mmol) were suspended in distilled P(OEt)3
(100 mL) and heated to 130 °C (during heating the two solids
dissolved leaving a red solution and after 10-15 min a yellow
orange precipitate was formed). Two additional portions of 4,5-
bis(2-cyanoethylthio)-1,3-dithiole-2-thione (a´ 1.47 g, 4.82 mmol)
were added after 10 and 20 min, respectively. The red reaction
mixture was stirred for 1 h at 130 °C, cooled to room
temperature and addition of MeOH (100 mL) yielded an orange
solid, which was filtered and washed with MeOH. The orange
powder was purified by column chromatography (silica gel,
CH2Cl2, Rf ) 0.2) to give 3.51 g (64%) of pure 22c as an orange
solid. Recrystallization from CH2Cl2/petroleum ether (bp 60-
80 °C) gave 22c as orange needles: mp 177-178 °C; 1H NMR
(DMSO-d6) δ 2.38 (s, 3H), 2.86 (t, J ) 6.6 Hz, 4H), 3.14 (t, J )
6.6 Hz, 4H), 7.39 (s, 2H), 7.46 (d, J ) 8.6 Hz, 2H), 7.82 (d, J
) 8.6 Hz, 2H); 13C NMR (DMSO-d6) δ 18.1, 21.0, 30.8, 112.0,
112.7, 118.1, 118.8, 125.9, 126.7, 127.2, 130.4, 134.4, 145.8;
MS (EI) m/z 567 (M+, 2); IR (KBr) ν 2251 (CN), 1375 (SO2),
1172 (SO2) cm-1. Anal. Calcd for C21H17N3O2S7: C, 44.42; H,
3.02; N, 7.40; S, 39.53. Found: C, 44.53; H, 2.98; N, 7.27; S,
39.63.
Gen er a l P r oced u r e for Detosyla tion of 22a a n d 22b.
A solution of 22a or 22b in anhyd THF-MeOH (1:1 v/v) was
degassed (N2, 15 min) before NaOMe (30% solution in MeOH,
15 equiv) was added in one portion. The yellow solution was
refluxed for 20 min, and after cooling to room temperature
purification was performed as described below.
2-[4,5-Bis(m eth ylth io)-1,3-dith iole-2-yliden e]-(1,3)-dith i-
olo[4,5-c]p yr r ole (23a ). 22a (0.37 g, 0.76 mmol) and THF-
MeOH (1:1 v/v, 50 mL). Removal of the solvent gave a yellow
residue, which was dissolved in CH2Cl2 (60 mL), washed with
H2O, and dried (MgSO4). Concentration in vacuo gave a yellow
orange solid, which was purified by column chromatography
(silica gel, CH2Cl2, Rf ) 0.3) to give 0.24 g (95%) of 23a as an
analytically pure yellow orange solid: mp 143.5-144 °C dec;
1H NMR (DMSO-d6) δ 2.44 (s, 6H), 6.81 (d, J ) 2.9 Hz, 2H),
11.14 (bs, 1H); 13C NMR (DMSO-d6) δ 18.4, 107.3, 110.9, 117.2,
122.0, 126.2; MS (EI) m/z 335 (M+, 100), 320 (M+ - CH3, 24).
Anal. Calcd for C10H9NS6: C, 35.80; H, 2.70; N, 4.17; S, 57.33.
Found: C, 35.91; H, 2.68; N, 4.15; S, 57.15.
2-[4,5-Bis(pen tylth io)-1,3-dith iole-2-yliden e]-(1,3)-dith i-
olo[4,5-c]p yr r ole (23b). 22b (2.69 g, 4.47 mmol) and THF-
MeOH (1:1 v/v, 100 mL). Removal of the solvent gave a yellow
residue, which was dissolved in CH2Cl2 (150 mL), washed with
H2O and brine, and dried (MgSO4). Concentration in vacuo
gave a yellow orange solid, which was purified by column
chromatography (silica gel, CH2Cl2, Rf ) 0.6) to give 1.77 g
(88%) of 23b as a dark oil, which upon standing solidifed giving
23b as analytically pure yellow crystals: mp 62-63 °C; 1H
NMR (DMSO-d6) δ 0.86 (t, J ) 7.0 Hz, 6H), 1.20-1.50 (m, 8H),
1.57 (quintet, J ) 7.0 Hz, 4H), 2.85 (t, J ) 7.0 Hz, 4H), 6.81
(d, J ) 2.3 Hz, 2H), 11.13 (bs, 1H); 13C NMR (DMSO-d6) δ
13.7, 21.5, 28.8, 29.8, 35.2, 107.3, 110.6, 117.0, 121.5, 126.6;
MS (EI) m/z 447 (M+, 100). Anal. Calcd for C18H25NS6: C,
48.28; H, 5.63; N, 3.13; S, 42.96. Found: C, 48.48; H, 5.57; N,
3.24; S, 42.84.
Gen er a l P r oced u r e for N-Alk yla tion of 23a . Compound
23a (20.2 mg, 0.060 mmol) was dissolved in anhyd DMF (3
mL) and degassed (N2, 15 min) before hexane washed sodium
hydride (10 mg, 0.42 mmol) was added in one portion. The
mixture was stirred for 15 min at room temperature, causing
the initially yellow solution to become orange, whereupon the
alkylating reagent was added in one portion, causing a color
change to yellow. The reaction mixture was stirred for 1 h at
N-Bu tyl-2-[4,5-bis(m eth ylth io)-1,3-d ith iole-2-ylid en e]-
(1,3)-d ith iolo[4,5-c]p yr r ole (24b). Meth od 1. Alkylation
using butyl bromide (0.10 mL of a 0.90 M solution in DMF,
0.090 mmol): Rf ) 0.8 (CH2Cl2); yield 21.0 mg (89%). Recrys-
tallization from CH2Cl2/petroleum ether (bp 60-80 °C) gave
24b as yellow plates suitable for X-ray analysis: mp 105.5-
106 °C; 1H NMR (CDCl3) δ 0.92 (t, J ) 7.3 Hz, 3H), 1.30 (sextet,
J ) 7.3 Hz, 2H), 1.70 (quintet, J ) 7.3 Hz, 2H), 2.42 (s, 6H),
3.81 (t, J ) 7.3 Hz, 2H), 6.45 (s, 2H); 13C NMR (CDCl3) δ 13.5,
19.1, 19.6, 33.4, 50.5, 110.2, 112.5, 118.5, 121.3, 127.3; MS (EI)
m/z 391 (M+, 100), 376 (M+ - CH3, 20). Anal. Calcd for C14H17
-
NS6: C, 42.93; H, 4.37; N, 3.58; S, 49.11. Found: C, 43.03; H,
4.34; N, 3.69; S, 48.99.
N-Ben zyl-2-[4,5-bis(m eth ylth io)-1,3-dith iole-2-ylid en e]-
(1,3)-d ith iolo[4,5-c]p yr r ole (24c). Like 24a ,b, except that
the reaction was performed on a larger scale. Compound 23a
(70.0 mg, 0.21 mmol), DMF (10 mL) and NaH (50 mg, 2.1
mmol). Alkylation using benzyl bromide (0.25 mL, 0.36 g, 2.10
mmol): Rf ) 0.25 (CH2Cl2/cyclohexane 1:4); yield 80.0 mg
(90%). Recrystallization from CH2Cl2/petroleum ether (bp 60-
80 °C) gave 24c as yellow needles: mp 133-134 °C; 1H NMR
(DMSO-d6) δ 2.43 (s, 6H), 5.07 (s, 2H), 6.88 (s, 2H), 7.27 (m,
5H); 13C NMR (DMSO-d6) δ 18.4, 53.3, 107.7, 113.9, 117.3,
121.0, 126.0, 127.2, 127.6, 128.6, 138.2; MS (EI) m/z 425 (M+,
76), 410 (M+ - CH3, 11). Anal. Calcd for C17H15NS6: C, 47.97;
H, 3.55; N, 3.29; S, 45.19. Found: C, 48.09; H, 3.52; N, 3.21;
S, 45.23.
P oten tia l of 22c a s a Bu ild in g Block for Su p r a m olecu -
la r Ch em istr y. 2-[4-(2-Cya n oeth ylth io)-5-m eth ylth io-1,3-
dith iole-2-yliden e]-N-tosyl-(1,3)-dith iolo[4,5-c]pyr r ole (25).
A solution of 22c (0.100 g, 0.18 mmol) in anhyd THF (10 mL)
was degassed (N2, 15 min) before a solution of CsOH‚H2O
(0.032 g, 0.19 mmol) in anhyd MeOH (1 mL) was added
dropwise via a syringe over a period of 1 h. The mixture was
stirred for 15 min, whereupon MeI (0.52 mL, excess) was added
in one portion. After stirring for further 30 min and removal
of the solvent, the yellow residue was purified by column
chromatography (silica gel, CH2Cl2/cyclohexane 2:1, Rf ) 0.35)
to give 0.089 g (96%) of 25 as an analytically pure yellow
solid: mp 186.5-187 °C (CH2Cl2/cyclohexane); 1H NMR (DMSO-
d6) δ 2.39 (s, 3H), 2.47 (s, 3H), 2.83 (t, J ) 6.6 Hz, 2H), 3.10 (t,
J ) 6.6 Hz, 2H), 7.39 (s, 2H), 7.46 (d, J ) 8.2 Hz, 2H), 7.82 (d,
J ) 8.2 Hz, 2H); 13C NMR (DMSO-d6) δ 18.0, 18.4, 21.0, 30.7,
112.2, 112.6, 117.6, 118.7, 120.6, 125.8, 125.8, 126.7, 130.3,
132.5, 134.3, 145.7 two lines overlapping; MS (EI) m/z 528 (M+,
40), 373 (M+ - Ts, 71); IR (KBr) ν 2251 (CN), 1372 (SO2), 1172
(SO2) cm-1. Anal. Calcd for C19H16N2O2S7: C, 43.16; H, 3.05;
N, 5.29; S, 42.45. Found: C, 43.21; H, 3.03; N, 5.20; S, 42.54.
2-[4,5-Bis(m eth ylth io)-1,3-d ith iole-2-ylid en e]-N-tosyl-
(1,3)-d ith iolo[4,5-c]p yr r ole 22a . Meth od 2. A solution of 25
(0.050 g, 0.095 mmol) in anhyd THF (10 mL) was degassed
(N2, 15 min) before a solution of CsOH‚H2O (0.017 g, 0.10
mmol) in anhyd MeOH (1 mL) was added dropwise via a
syringe over a period of 1 h. The mixture was stirred for 15
min, whereupon MeI (0.10 mL, excess) was added in one
portion. After stirring for further 30 min and removal of the
solvent the yellow residue was purified by column chroma-
tography (silica gel, CH2Cl2/cyclohexane 1:1, Rf ) 0.3) to give

Pyrrolo-Annelated Tetrathiafulvalenes
J . Org. Chem., Vol. 65, No. 18, 2000 5803
0.044 g (95%) of pure 22a as a yellow solid: mp 157-158 °C
(CH2Cl2/cyclohexane).
1055 (CdS) cm-1. Anal. Calcd for C7H9NOS3: C, 38.83; H, 4.14;
N, 6.39. Found: C, 38.55; H, 4.27; N, 6.31.
N-(2-ter t-Bu tyld ip h en ylsiloxyeth yl)-4,6-d ih yd r o-(1,3)-
d ith iolo[4,5-c]p yr r ole-2-th ion e (26d ). Meth od 1. To a
solution of 26c (0.44 g, 2.00 mmol) in anhyd DMF (20 mL)
was first added tert-butyldiphenylchlorosilane (0.60 mL, 0.63
g, 2.30 mmol) in one portion followed by imidazole (1.50 g, 22.0
mmol). The yellow solution was stirred overnight at room
temperature, whereupon the solvent was evaporated in vacuo.
The brown oily residue was dissolved in CH2Cl2 (150 mL),
washed with H2O and dried (MgSO4), after which the solvent
was evaporated. The resulting yellowish brown residue was
purified by column chromatography (silica gel, CH2Cl2, Rf )
0.2) to give 0.74 g (81%) of 26d as a dark yellow oil. Leaving
Meth od 3. A solution of 22c (0.20 g, 0.35 mmol) in anhyd
THF (15 mL) was degassed (N2, 15 min) before a solution of
CsOH‚H2O (0.062 g, 0.37 mmol) in anhyd MeOH (1 mL) was
added dropwise via a syringe over a period of 1 h. The mixture
was stirred for 15 min, whereupon MeI (0.44 mL, excess) was
added in one portion. After stirring for further 45 min the
solvent and excess of MeI were removed in vacuo. The yellow
residue was redissolved in THF (15 mL) and degassed (N2, 15
min) before a solution of CsOH‚H2O (0.062 g, 0.37 mmol) in
anhyd MeOH (1 mL) was added dropwise via a syringe over a
period of 1 h. MeI (0.44 mL, excess) was added in one portion
and after removal of the solvent the yellow residue was
purified by column chromatography (silica gel, CH2Cl2/cyclo-
hexane 1:1, Rf ) 0.3) to give 0.16 g (93%) of pure 22a as a
yellow solid: mp 158-159 °C (CH2Cl2/cyclohexane). The
spectroscopic data for 22a obtained by methods 2 and 3 were
identical to those reported by method 1.
R in g Closu r e R ea ct ion Bet w een 14 a n d P r im a r y
Am in es. N-Bu tyl-4,6-d ih yd r o-(1,3)-d ith iolo[4,5-c]p yr r ole-
2-th ion e (26a ). Butylamine (0.73 g, 9.98 mmol) was added in
one portion to a refluxing mixture of 14 (3.20 g, 10.0 mmol)
and cesium carbonate (13 g, 40 mmol) in THF-CH3CN (300
mL,1:2 v/v), whereupon the mixture was refluxed for 45 min.
After the mixture was cooled to room temperature, the solvent
was removed in vacuo. The residue was dissolved in CH2Cl2
(300 mL), washed with H2O, and dried (MgSO4). The organic
phase was concentrated in vacuo and the crude product
purified by column chromatography (silica gel, first CH2Cl2
then CH2Cl2/EtOAc 10:1, Rf ) 0.4) to give 1.83 g (79%) of pure
26a as a yellow oil, which upon cooling solidified. Recrystal-
lization from hexane gave 26a as yellow micro crystals: mp
105.5-106 °C; 1H NMR (CDCl3) δ 0.94 (t, J ) 7.2 Hz, 3H),
1.39 (sextet, J ) 7.2 Hz, 2H), 1.50 (quintet, J ) 7.2 Hz, 2H),
2.74 (t, J ) 7.2 Hz, 2H), 3.85 (s, 4H); 13C NMR (CDCl3) δ 13.9,
20.3, 30.8, 56.0, 57.4, 138.6, 217.6; MS (EI) m/z 231 (M+, 42);
IR (KBr) ν 1055 (CdS) cm-1. Anal. Calcd for C9H13NS3: C,
46.72; H, 5.66; N, 6.05. Found: C, 46.87; H, 5.58; N, 5.95.
4,6-Dih yd r o-N-[2-(tetr a h yd r op yr a n -2-oxy)eth yl]-(1,3)-
d ith iolo[4,5-c]p yr r ole-2-th ion e (26b). 2-(Tetrahydropyran-
2-oxy)ethylamine (2.91 g, 20.0 mmol) was added in one portion
to a refluxing mixture of 14 (6.40 g, 20.0 mmol) and cesium
carbonate (26 g, 80 mmol) in THF-CH3CN (600 mL,1:2 v/v),
whereupon the mixture was refluxed for 1 h. After cooling to
room temperature, the solvent was removed in vacuo and the
yellow residue was dissolved in CH2Cl2 (400 mL), washed with
H2O and dried (Na2SO4). Concentration in vacuo gave a brown
oil, which was purified by column chromatography (silica gel,
CH2Cl2/EtOAc 2:1, Rf ) 0.3) to give 4.44 g (73%) of 26b as an
analytically pure light brown oil: 1H NMR (CDCl3) δ 1.50-
1.80 (m, 6H), 3.03 (t, J ) 5.5 Hz, 2H), 3.50-3.60 (m, 2H), 3.86-
3.93 (m, 2H), 3.97 (s, 4H), 4.60 (bs, 1H); 13C NMR (CDCl3) δ
19.5, 25.2, 30.5, 55.5, 57.9, 62.4, 66.4, 99.1, 138.7, 217.7; MS
(EI) m/z 303 (M+, 17); IR (neat) ν 1057 (CdS) cm-1. Anal. Calcd
for C12H17NO2S3: C, 47.50; H, 5.65; N, 4.62. Found: C, 47.67;
H, 5.57; N, 4.59.
4,6-Dih ydr o-N-(2-h ydr oxyeth yl)-(1,3)-dith iolo[4,5-c]pyr -
r ole-2-th ion e (26c). To a well stirred solution of 26b (4.44 g,
14.63 mmol) in acetone-MeOH (300 mL, 2:1 v/v) was added a
2 M HCl solution (20 mL) and the yellow reaction mixture was
stirred overnight at room temperature. The solvent was
removed in vacuo (T < 30 °C) and the yellow oily residue was
treated with saturated aqueous NaHCO3 solution (150 mL)
to precipitate the product, which was collected by filtration,
washed with H2O and dried in vacuo to give 2.50 g (78%) of
pure 26c as a yellow powder. Extraction of the filtrate with
EtOAc followed by drying of the combined organic phases (Na2-
SO4) and concentration in vacuo gave 0.64 g (20%) of pure 26c
as a yellow powder. Recrystallization from toluene/cyclohexane
gave 26c as yellow needles: mp 101.5-102 °C; 1H NMR
(CDCl3) δ 2.38 (bs, 1H), 2.98 (t, J ) 5.2 Hz, 2H), 3.69 (t, J )
5.2 Hz, 2H), 3.94 (s, 4H); 13C NMR (CDCl3) δ 57.6, 58.0, 60.1,
138.3, 217.6; MS (EI) m/z 219 (M+, 91); IR (KBr) ν 3154 (OH),
the product in
a vacuum overnight afforded 26d as an
analytically pure yellow solid: mp 87-88.5 °C.
Meth od 2. 2-Aminoethanol (0.60 mL, 0.87 g, 14.2 mmol)
was added in one portion to a refluxing mixture of 14 (3.20 g,
10.0 mmol) and cesium carbonate (13 g, 40 mmol) in THF-
CH3CN (300 mL,1:2 v/v), whereupon the mixture was refluxed
for 30 min. After cooling to room temperature, the solvent was
removed in vacuo. The yellowish brown residue was dissolved
in EtOAc (400 mL) and washed with H2O. The aqueous phase
was extracted with EtOAc (3 × 150 mL) and the combined
organic phases were dried (Na2SO4). Concentration in vacuo
gave a yellow solid, which was redissolved in anhyd DMF (100
mL) and tert-butyldiphenylchlorosilane (3.00 mL, 3.17 g, 11.5
mmol) was added in one portion followed by imidazole (8.0 g,
118 mmol). The orange solution was stirred for 45 min,
whereupon the solvent was evaporated in vacuo. The brown
oily residue was dissolved in CH2Cl2 (300 mL), washed with
H2O and dried (MgSO4). Concentration in vacuo gave a brown
residue which was purified by column chromatography (silica
gel, CH2Cl2, Rf ) 0.2) to give 1.95 g (43%) of 26d as a dark
yellow oil. Leaving the product in a vacuum overnight afforded
1
26d as an analytically pure yellow solid: mp 87.5-89 °C; H
NMR (CDCl3) δ 1.06 (s, 9H), 2.94 (t, J ) 5.6 Hz, 2H), 3.80 (t,
J ) 5.6 Hz, 2H), 3.87 (s, 4H), 7.41 (m, 6H), 7.67 (m, 4H); 13C
NMR (CDCl3) δ 19.0, 26.7, 57.8, 58.0, 63.3, 127.8, 129.8, 133.5,
t
135.6, 138.7, 217.8; MS (EI) m/z 457 (M+, 3), 400 (M+ - Bu,
40); IR (KBr) ν 1059 (CdS) cm-1. Anal. Calcd for C23H27NOS3-
Si: C, 60.35; H, 5.95; N, 3.06. Found: C, 60.13; H, 5.99; N,
3.04.
N-Bu tyl-4,6-d ih yd r o-2-[4,5-bis(2-m eth ylth io)-1,3-d ith i-
ole-2-ylid en e]-(1,3)-d ith iolo[4,5-c]p yr r ole (27a ). A mixture
of 26a (0.46 g, 1.99 mmol) and 4,5-bis(methylthio)-1,3-dithiol-
2-one (0.63 g, 3.00 mmol) in neat P(OEt)3 (10 mL) was refluxed
for 30 min, whereupon additional 4,5-bis(methylthio)-1,3-
dithiol-2-one (0.63 g, 3.00 mmol) was added in one portion and
the red mixture was refluxed for further 1.5 h. After the
mixture was cooled to room temperature, excess P(OEt)3 was
evaporated in vacuo and the red residue was purified by
column chromatography (silica gel, EtOAc/hexane 1:10, Rf )
0.5) to give 0.27 g (34%) of pure 27a as orange crystals.
Recrystallization from hexane afforded 27a as orange-rod like
cystals: mp 78-79 °C; 1H NMR (CDCl3) δ 0.93 (t, J ) 7.2 Hz,
3H), 1.36 (sextet, J ) 7.2 Hz, 2H), 1.47 (quintet, J ) 7.2 Hz,
2H), 2.42 (s, 6H), 2.70 (t, J ) 7.2 Hz, 2H), 3.62 (s, 2H); 13C
NMR (CDCl3) δ 14.0, 19.2, 20.3, 30.9, 56.5, 57.3, 108.2, 120.4,
127.4, 129.6; FAB (EI) m/z 393 (M+, 100). Anal. Calcd for
C
14H19NS6: C, 42.71; H, 4.86; N, 3.56. Found: C, 42.48; H,
4.49; N, 3.52.
2-[4,5-Bis(2-cya n oeth ylth io)-1,3-d ith iole-2-ylid en e]-4,6-
dih ydr o-N-[2-(tetr ah ydr opyr an -2-oxy)eth yl]-(1,3)-dith iolo-
[4,5-c]p yr r ole (27b). A mixture of 26b (0.45 g, 1.48 mmol)
and 4,5-bis(2-cyanoethylthio)-1,3-dithiol-2-one (1.06 g, 3.67
mmol) in P(OMe)3 (10 mL) and toluene was refluxed for 30
min, whereupon additional 4,5-bis(2-cyanoethylthio)-1,3-dithiol-
2-one (0.70 g, 2.43 mmol) was added in one portion and the
orange red mixture was refluxed for further 2 h. Upon cooling
MeOH (40 mL) was added and the orange solid that precipi-
tated (tetrakis(2-cyanoethylthio)TTF) was collected by filtra-
tion. The filtrate was concentrated in vacuo and the orange
red residue was purified by column chromatography (silica gel,
CH2Cl2/CH3CN 4:1, Rf ) 0.3) giving an orange powder, which

5804 J . Org. Chem., Vol. 65, No. 18, 2000
J eppesen et al.
was recrystallized from toluene/petroleum ether (bp 60-80 °C)
to give 0.25 g (31%) of 27b as fine orange crystals: mp 117-
118 °C dec; 1H NMR (CDCl3) δ 1.50-1.80 (m, 6H), 2.74 (t, J )
7.0 Hz, 4H), 2.98 (t, J ) 5.7 Hz, 2H), 3.09 (t, J ) 7.0 Hz, 4H),
3.49-3.55 (m, 2H), 3.74 (s, 4H), 3.84-3.89 (m, 2H), 4.62 (m,
1H); 13C NMR (CDCl3) δ 18.7, 19.5, 25.3, 30.5, 31.1, 56.0, 57.8,
62.4, 66.5, 99.1, 105.4, 117.5, 124.1, 128.1, 129.7; MS (FAB)
m/z 543 (M+, 100); IR (KBr) ν 2250 (CN) cm-1. Anal. Calcd for
of the filtrate gave a dark brown oil, which was purified by
column chromatography (silica gel, CH2Cl2, Rf ) 0.7) to give
1.01 g (89%) of 29a as an analytically pure dark brown oil,
which solidified upon cooling: mp 40-41 °C; 1H NMR (CDCl3)
δ 0.94 (t, J ) 7.2 Hz, 3H), 1.32 (sextet, J ) 7.2 Hz, 2H), 1.78
(quintet, J ) 7.2 Hz, 2H), 3.97 (t, J ) 7.2 Hz, 2H), 6.70 (s,
2H); 13C NMR (CDCl3) δ 13.5, 19.7, 33.4, 51.0, 111.7, 122.6,
219.5; MS (EI) m/z 229 (M+, 100); IR (neat) ν 1047 (CdS) cm-1
.
C
21H25N3O2S6: C, 46.38; H, 4.63; N, 7.73. Found: C, 46.34; H,
Anal. Calcd for C9H11NS3: C, 47.13; H, 4.83; N, 6.11. Found:
C, 47.18; H, 4.81; N, 6.08.
4.60; N, 7.65.
N-(2-ter t-Bu tyld ip h en ylsiloxyeth yl)-2-[4,5-bis(2-cya n o-
eth ylth io)-1,3-dith iole-2-yliden e]-4,6-dih ydr o-(1,3)-dith iolo-
[4,5-c]p yr r ole (27d ). Compound 26d (0.64 g, 1.40 mmol) and
4,5-bis(2-cyanoethylthio)-1,3-dithiol-2-one (0.40 g, 1.40 mmol)
were suspended in distilled P(OEt)3 (30 mL) and heated to 135
°C (during heating the two solids dissolved and an orange
precipitate of tetrakis(2-cyanoethylthio)TTF was formed). Then
4,5-bis(2-cyanoethylthio)-1,3-dithiol-2-one (0.40 g, 1.40 mmol)
was added in one portion and the orange red suspension was
stirred for 30 min at 135 °C, followed by an addition of 4,5-
bis(2-cyanoethylthio)-1,3-dithiol-2-one (0.40 g, 1.40 mmol). The
orange red suspension was stirred for further 30 min at 135
°C and cooled to room temperature. Addition of MeOH (20 mL)
yielded an orange solid, which was filtered and washed with
MeOH. The combined filtrate was concentrated in vacuo and
the resulting orange red oil was purified by column chroma-
tography (silica gel, CH2Cl2/EtOAC 19:1, Rf ) 0.3) to give 0.36
g (37%) of 27d as an orange oil. The product is sufficiently
pure (NMR and TLC) for further reaction, but can be purified
further by column chromatography (silica gel, CH2Cl2/EtOAC
19:1, Rf ) 0.3) to give 0.33 g (34%) of 27d as an analytically
pure orange oil: 1H NMR (CDCl3) δ 1.05 (s, 9H), 2.73 (t, J )
7.1 Hz, 4H), 2.91 (t, J ) 5.8 Hz, 2H), 3.08 (t, J ) 7.1 Hz, 4H),
3.68 (s, 4H), 3.76 (t, J ) 5.8 Hz, 2H), 7.40 (m, 6H), 7.67 (m,
4H); 13C NMR (CDCl3) δ 18.7, 18.9, 26.7, 31.1, 57.8, 58.2, 63.2,
105.4, 117.5, 124.0, 127.7, 128.0, 129.7, 129.7, 133.4, 135.6;
MS (FAB) m/z 697 (M+, 100); IR (neat) ν 2250 (CN) cm-1. Anal.
Calcd for C32H35N3OS6Si: C, 55.06; H, 5.05; N, 6.02. Found:
C, 55.27; H, 5.18; N, 5.90.
N-(2-ter t-Bu tyld ip h en ylsiloxyeth yl)-(1,3)-d ith iolo[4,5-
c]p yr r ole-2-th ion e (29d ). A mixture of 26d (0.13 g, 0.28
mmol) and DDQ (0.13 g, 0.57 mmol) in anhyd toluene (15 mL)
was stirred for 15 min at room temperature, whereupon the
solvent was removed in vacuo. The dark red residue was
purified by column chromatography (silica gel, CH2Cl2, Rf )
0.6) to give 0.11 g (86%) of 29d as a brownish yellow oil.
Leaving the product in a vacuum overnight afforded 29d as
an analytically pure yellow solid: mp 77.5-79 °C; 1H NMR
(CDCl3) δ 1.02 (s, 9H), 3.86 (t, J ) 5.0 Hz, 2H), 4.06 (t, J ) 5.0
Hz, 2H), 6.68 (s, 2H), 7.32-7.50 (m, 10H); 13C NMR (CDCl3) δ
18.9, 26.6, 53.4, 63.8, 112.4, 123.0, 127.9, 130.0, 132.7, 135.5,
219.8; MS(EI) m/z 455 (M+, 11), 398 (M+ - tBu, 100); IR (KBr)
ν 1040 (CdS) cm-1. Anal. Calcd for C23H25NOS3Si: C, 60.62;
H, 5.53; N, 3.07; S, 21.11. Found: C, 60.47; H, 5.47; N, 3.13;
S, 21.20.
N-Bu tyl-2-[4,5-bis(2-m eth ylth io)-1,3-dith iole-2-yliden e]-
(1,3)-d ith iolo[4,5-c]p yr r ole (24b). Meth od 2. A mixture of
29a (1.37 g, 5.97 mmol) and 4,5-bis(methylthio)-1,3-dithiol-2-
one (1.88 g, 8.94 mmol) in neat P(OEt)3 (30 mL) was refluxed
for 30 min, whereupon additional 4,5-bis(methylthio)-1,3-
dithiol-2-one (1.88 g, 8.94 mmol) was added in one portion and
the red mixture was refluxed for further 1 h. After cooling to
room temperature, excess P(OEt)3 was evaporated in vacuo
and the red residue was purified by column chromatography
(silica gel, EtOAc/hexane 1:10, Rf ) 0.40) to give 1.30 g (56%)
of 24b as orange crystals. The complete separation of 24b from
tetrakis(methylthio)TTF may require two or three runs of
column chromatography. Recrystallization from CH2Cl2/hex-
ane afforded orange plates of 24b suitable for X-ray analysis:
mp 107-108 °C. The spectroscopic data for 24b obtained by
Method 2 were identical to those reported by Method 1.
N-(2-ter t-Bu tyld ip h en ylsiloxyeth yl)-2-[4,5-bis(2-cya n o-
eth ylth io)-1,3-d ith iole-2-ylid en e]-(1,3)-d ith iolo[4,5-c]p yr -
r ole (30). A mixture of 29d (0.34 g, 0.75 mmol) and 4,5-bis(2-
cyanoethylthio)-1,3-dithiol-2-one (0.22 g, 0.76 mmol) in distilled
P(OEt)3 (20 mL) was heated to 135 °C (during heating the two
solids dissolved and an orange precipitate of tetrakis(2-
cyanoethylthio)TTF was formed). Then 4,5-bis(2-cyanoeth-
ylthio)-1,3-dithiol-2-one (0.22 g, 0.76 mmol) was added in one
portion and the orange red suspension was stirred for 30 min
at 135 °C, followed by addition 4,5-bis(2-cyanoethylthio)-1,3-
dithiol-2-one (0.22 g, 0.76 mmol). The orange red suspension
was stirred for further 30 min at 135 °C and cooled to room
temperature. Addition of MeOH (30 mL) yielded an orange
solid, which was filtered and washed with MeOH. The
combined filtrate was concentrated in vacuo and the resulting
dark red oil was purified by column chromatography (silica
gel, CH2Cl2, Rf ) 0.25) to give 0.16 g (31%) of 30 as an orange
oil. The product is sufficiently pure (NMR and TLC) for further
reactions, but can be purified further by column chromatog-
raphy to give 30 as an orange oil containing a small amount
of CH2Cl2: 1H NMR (CDCl3) δ 1.02 (s, 9H), 2.74 (t, J ) 7.1
Hz, 4H), 3.09 (t, J ) 7.1 Hz, 4H), 3.80 (t, J ) 5.1 Hz, 2H), 3.93
(t, J ) 5.1 Hz, 2H), 6.48 (s, 2H), 7.33-7.52 (m, 10H); 13C NMR
(CDCl3) δ 18.7, 19.0, 26.6, 31.2, 53.0, 64.0, 106.6, 113.2, 117.5,
118.5, 124.8, 127.8, 127.9, 129.9, 132.9, 135.6; MS(EI) m/z 695
(M+, 55); IR (neat) ν 2250 (CN) cm-1. Anal. Calcd for C32H33N3-
OS6Si: C, 55.22; H, 4.78; N, 6.04; S, 27.63 and C32H33N3OS6-
Si‚0.7CH2Cl2: C, 51.98; H, 4.59; N, 5.56; S, 25.46. Found: C,
51.93; H, 4.57; N, 5.59; S, 25.90.
2-[4,5-Bis(2-cya n oeth ylth io)-1,3-d ith iole-2-ylid en e]-4,6-
d ih yd r o-N-(2-h yd r oxyeth yl)-(1,3)-d ith iolo[4,5-c]p yr r ole
(28). Meth od 1. To a solution of 27b (0.50 g, 0.92 mmol) in
acetone-MeOH (80 mL, 2:1 v/v) was added a 2M HCl solution
(6 mL) and the orange solution was stirred overnight at room
temperature, whereupon a saturated aqueous NaHCO3 solu-
tion (50 mL) was added and the mixture was concentrated in
vacuo to give an orange precipitate, which was collected by
filtration, washed with H2O and dried in vacuo. Recrystalli-
zation from EtOH gave 0.35 g (83%) of 28 as fine orange
needles: mp 152-153 °C dec.
Meth od 2. A solution of 4 M HCl (0.07 mL, 0.28 mmol) was
via a syringe added to a solution of 27d (0.18 g, 0.26 mmol) in
THF (10 mL) in one portion, whereupon TBAF (0.38 mL of a
1.0 M solution in THF, 0.38 mmol) was added dropwise to the
orange red mixture. The reaction mixture was stirred at room
temperature for 24 h, followed by addition of TBAF (0.38 mL
of a 1.0 M solution in THF, 0.38 mmol) and stirred for further
16 h, after which saturated aqueous NaHCO3 solution (25 mL)
was added to precipitate the product, which was collected by
filtration, washed with H2O and dried in vacuo. Recrystalli-
zation from 2-propanol gave 0.063 g (54%) of 28 as an orange
1
powder: mp 146-148 °C; H NMR (DMSO-d6) δ 2.74 (t, J )
6.0 Hz, 2H), 2.87 (t, J ) 6.6 Hz, 4H), 3.15 (t, J ) 6.6 Hz, 4H),
3.46 (m, 2H), 3.64 (s, 4H), 4.53 (t, J ) 5.3 Hz, 1H); 13C NMR
(DMSO-d6) δ 18.2, 30.8, 57.3, 58.3, 59.9, 105.9, 119.0, 121.2,
127.7, 129.7; MS (FAB) m/z 459 (M+, 100); IR (KBr) ν 2251
(CN) cm-1. Anal. Calcd for C16H17N3OS6: C, 41.81; H, 3.73;
N, 9.14. Found: C, 41.70; H, 3.84; N, 8.85.
N-Bu tyl-(1,3)-d ith iolo[4,5-c]p yr r ole-2-th ion e (29a ). A
mixture of 26a (1.15 g, 4.97 mmol) and DDQ (1.25 g, 5.51
mmol) in anhyd toluene (50 mL) was refluxed for 1 h. After
cooling to room temperature, the precipitate was removed by
filtration, and the filtrate was washed with 10% aqueous
NaOH solution and dried (MgSO4). The toluene solution was
filtered through a pad of silica gel (3 cm), and concentration
2-[4,5-Bis(2-cya n oeth ylth io)-1,3-d ith iole-2-ylid en e]-N-
(2-h yd r oxyeth yl)-(1,3)-d ith iolo[4,5-c]p yr r ole (31). Com-
pound 30 (0.066 g, 0.095 mmol) was dissolved in anhyd THF
(5 mL) and a 4 M HCl solution (0.05 mL, 0.20 mmol) was added

Pyrrolo-Annelated Tetrathiafulvalenes
J . Org. Chem., Vol. 65, No. 18, 2000 5805
to the orange solution in one portion, followed by addition of
TBAF (0.14 mL of a 1.0 M solution in THF, 0.14 mmol). The
orange solution was stirred at room temperature for 45 min,
whereupon additional TBAF (0.16 mL of a 1.0 M solution in
THF, 0.16 mmol) was added. The reaction mixture was stirred
for further 15 h and the solvent was evaporated in vacuo. The
resulting orange oil was dissolved in EtOAc (40 mL), washed
with H2O, and dried (Na2SO4). Concentration in vacuo gave
an orange solid, which was purified by column chromatography
(silica gel, EtOAc, Rf ) 0.4) to give 0.040 g (92%) of 31 as an
analytically pure orange solid. Recrystallization from toluene/
petroleum ether (bp 60-80 °C) gave 31 as an orange powder:
mp 130-131 °C; 1H NMR (DMSO-d6) δ 2.88 (t, J ) 6.7 Hz,
4H), 3.15 (t, J ) 6.7 Hz, 4H), 3.60 (t, J ) 5.1 Hz, 2H), 3.89 (t,
J ) 5.1 Hz, 2H), 4.89 (bs, 1H), 6.84 (s, 2H); 13C NMR (DMSO-
d6) δ 18.1, 30.7, 52.6, 61.1, 106.8, 114.0, 116.5, 118.9, 121.8,
in CH3CN. The resulting green solution was allowed to cool
to room temperature and the crystals that precipitated was
collected by filtration to give 7‚TCNQ as black plates: mp 220
°C (dec without melting); IR (KBr) 2208 (CN), 2197 (CN) cm-1
.
Anal. Calcd for C22H10N6S4: C, 54.30; H, 2.07; N, 17.27.
Found: C, 53.70; H, 2.23; N, 16.60.
Ack n ow led gm en t. We thank University of Odense
for a Ph.D. scholarship to J .O.J ., the Danish Research
Academy for a postdoctoral fellowship to K.T., and
Bengt Lundquists minnesfond and Carlsbergfondet for
a postdoctoral fellowship to T.B.
Su p p or tin g In for m a tion Ava ila ble: X-ray crystal struc-
tures, crystal data, data collection details, and refinement
parameters for 22b and 24b. This material is available free
of charge via the Internet at http://pubs.acs.org.
127.3; MS(EI) m/z 457 (M+, 6); IR (KBr) ν 2250 (CN) cm-1
.
Anal. Calcd for C16H15N3OS6: C, 41.99; H, 3.30; N, 9.18; S,
42.03. Found: C, 41.88; H, 3.18; N, 9.02; S, 41.87.
Com p lex of Don or 7 w ith TCNQ. A hot solution of 7 (1
equiv) in CH3CN was added to a hot solution of TCNQ (1 equiv)
J O000742A