Stable Thioaminyl Radicals Having Functional Groups: Generation, ESR Spectra, Isolation, X-ray Crystallographic Analyses, and Magnetic Characterization of N-(Arylthio)-4-(ethoxycarbonyl)-2,6-diarylphenylaminyls, N-(Arylthio)-4-acetyl-2,6-diarylphenylaminyls, and N-(Arylthio)-4-cyano-2,6-diarylphenylaminyls

Article abstract of DOI:10.1021/jo9718206

Oxidation of N-(arylthio)-4-(ethoxycarbonyl)-2,6-diarylanilines (9), N-(arylthio)-4-acetyl-2,6-diarylanilines (10), and N-(arylthio)-4-cyano-2,6-diarylanilines (11) with PbO₂ yielded quite persistent N-(arylthio)-4-(ethoxycarbonyl)-2,6-diarylphenylaminyls(4), N-(arylthio)-4-acetyl-2,6-diarylphenylaminyls (5), and N-(arylthio)-4-cyano-2,6-diarylphenylaminyls (6), respectively, and they were isolated as pure radical crystals. On the other hand, N-(arylthio)-4-nitro-2,6-diarylphenylaminyls (6), and N-(arylthio)-4-chloro-2,6-diarylphenylaminyls (7), were unstable and soon decomposed. The X-ray crystallographic analyses of N-[(2,4-dichlorophenyl)thio]-4-acetyl-2,6-diphenylphenylaminyl (5c) and N-[(2,4-dichlorophenyl)thio]-4-cyano-2,6-diphenylphenylaminyl (6c) showed that the Ph-N-S-Ph π-framework is planar, and the 2- and 6-phenyl groups are twisted from the coplane. The ESR studies for 4-8 showed that their hyperfine coupling constants are nearly identical to each other and that the unpaired electron is extensively delocalized onto the anilino benzene ring and the arylthiyl group. The magnetic susceptibility measurements were carried out for five thioaminyl radical crystals and showed that one radical couples ferromagnetically with 2J/k_B = 16.0 K, and the other four radicals couple antiferromagnetically with 2J/k_B = -15.6 to -194.6 K or θ = -0.6 to -5.0 K.

Full text of DOI:10.1021/jo9718206

J . Org. Chem. 1998, 63, 1555-1565
1555
Sta ble Th ioa m in yl Ra d ica ls Ha vin g F u n ction a l Gr ou p s:
Gen er a tion , ESR Sp ectr a , Isola tion , X-r a y Cr ysta llogr a p h ic
An a lyses, a n d Ma gn etic Ch a r a cter iza tion of
N-(Ar ylth io)-4-(eth oxyca r bon yl)-2,6-d ia r ylp h en yla m in yls,
N-(Ar ylth io)-4-a cetyl-2,6-d ia r ylp h en yla m in yls, a n d
N-(Ar ylth io)-4-cya n o-2,6-d ia r ylp h en yla m in yls1
Yozo Miura,* Masayoshi Momoki, and Masaaki Nakatsuji
Department of Applied Chemistry, Faculty of Engineering, Osaka City University, Sumiyoshi-ku,
Osaka 558, J apan
Yoshio Teki
Department of Material Science, Faculty of Science, Osaka City University, Sumiyoshi-ku,
Osaka 558, J apan
Received October 2, 1997
Oxidation of N-(arylthio)-4-(ethoxycarbonyl)-2,6-diarylanilines (9), N-(arylthio)-4-acetyl-2,6-diaryl-
anilines (10), and N-(arylthio)-4-cyano-2,6-diarylanilines (11) with PbO2 yielded quite persistent
N-(arylthio)-4-(ethoxycarbonyl)-2,6-diarylphenylaminyls (4), N-(arylthio)-4-acetyl-2,6-diarylphenyl-
aminyls (5), and N-(arylthio)-4-cyano-2,6-diarylphenylaminyls (6), respectively, and they were
isolated as pure radical crystals. On the other hand, N-(arylthio)-4-nitro-2,6-diarylphenyl-
aminyls (6), and N-(arylthio)-4-chloro-2,6-diarylphenylaminyls (7), were unstable and soon
decomposed. The X-ray crystallographic analyses of N-[(2,4-dichlorophenyl)thio]-4-acetyl-2,6-
diphenylphenylaminyl (5c) and N-[(2,4-dichlorophenyl)thio]-4-cyano-2,6-diphenylphenylaminyl (6c)
showed that the Ph-N-S-Ph π-framework is planar, and the 2- and 6-phenyl groups are twisted
from the coplane. The ESR studies for 4-8 showed that their hyperfine coupling constants are
nearly identical to each other and that the unpaired electron is extensively delocalized onto the
anilino benzene ring and the arylthiyl group. The magnetic susceptibility measurements were
carried out for five thioaminyl radical crystals and showed that one radical couples ferromagnetically
with 2J /kB ) 16.0 K, and the other four radicals couple antiferromagnetically with 2J /kB ) -15.6
to -194.6 K or θ ) -0.6 to -5.0 K.
In tr od u ction
that, when having appropriate electron-withdrawing
substituents such as nitro or chloro in the phenylthiyl
group, they can be isolated as radical crystals (Chart
1).5-8 The magnetic measurements for the isolated
thioaminyl radicals carried out using solid radical
crystals showed that, although most thioaminyl radicals
couple antiferromagnetically, three radicals couple
ferromagnetically with the magnetic exchange inter-
actions of 2J /kB ) 3.6-28.0 K.9
In the present study we prepared N-(arylthio)-4-
(ethoxycarbonyl)-2,6-diarylphenylaminyls (4), N-(arylthio)-
4-acetyl-2,6-diarylphenylaminyls (5), N-(arylthio)-4-cyano-
2,6-diarylphenylaminyls (6), N-[(2,4-dichlorophenyl)thio]-
Although free radicals are generally transient due to
an electron vacancy in the highest occupied molecular
orbital, electronic stabilization and steric protection can
render them isolable. The well-known examples are
nitroxides, verdazyls, diphenylpicrylhydrazyl, and 2,4,6-
tri-tert-butylphenoxyl,2 which are well-known as the
isolable stable free radicals. In recent years, isolable
stable free radicals have attracted much attention in the
studies of molecule-based magnetism3 and “living” free
radical polymerization.4
In previous papers we reported that N-(arylthio)-2,4,6-
triarylphenylaminyls (1), N-(arylthio)-4-tert-butyl-2,6-
diarylphenylaminyls (2), and N-(arylthio)-2-tert-butyl-4,6-
diarylphenylaminyls (3) are quite persistent radicals, and
(5) (a) Miura, Y.; Tanaka, A. J . Chem. Soc., Chem. Commun. 1990,
441. (b) Miura, Y.; Tanaka, A.; Hirotsu, K. J . Org. Chem. 1991, 56,
6638.
(1) ESR Studies of Nitrogen-Centered Free Radicals. 49. Part 48:
Miura, Y.; Momoki, M.; Fuchikami, T.; Teki, Y.; Itoh, K.; Mizutani, H.
J . Org. Chem. 1996, 61, 4300.
(2) (a) Forrester, A. R.; Hay, J . M.; Thomson, H. R. Organic
Chemistry of Stable Free Radicals; Academic Press: London and New
York, 1968. (b) Rozantsev, E. G. Free Nitroxide Radicals; Plenum
Press: New York and London, 1970. (c) Volodarsky, L. B.; Reznikov,
V. A.; Ovcharenko, V. I. Chemistry of Stable Nitroxides; CRC Press:
Boca Raton, 1994.
(6) Miura, Y.; Kitagishi, Y.; Ueno, S. Bull. Chem. Soc. J pn. 1994,
67, 3282.
(7) Miura, Y.; Fuchikami, T.; Momoki, M. Chem. Lett. 1994, 2127,
and ref 1.
(8) (a) Miura, Y.; Yamano, E.; Tanaka, A.; Ogo, Y. Chem. Lett. 1992,
1831. (b) Miura, Y.; Yamano, E.; Tanaka, A.; Yamauchi, J . J . Org.
Chem. 1994, 59, 3294. (c) Miura, Y.; Oka, H.; Yamano, E.; Teki, Y.;
Takui, T.; Itoh, K. Bull. Chem. Soc. J pn. 1995, 68, 1187. (d) Miura,
Y. Yamano, E. J . Org. Chem. 1995, 60, 1070.
(3) Miller, J . S.; Epstein, A. J . Proceedings of the Symosium on the
4th International Conference on Molecule-Based Magnets, Mol. Cryst.
Liq. Cryst. 1995, 271, 1; 272, 1; 273, 1; 274, 1.
(9) (a) Teki, Y.; Miura, Y.; Tanaka, A.; Takui, T.; Itoh, K. Mol. Cryst.
Liq. Cryst. 1993, 233, 119. (b) Teki, Y.; Itoh, K.; Okada, A.; Yamakage,
H.; Kobayashi, T.; Amaya, K.; Kurokawa, S.; Ueno, S.; Miura, Y. Chem.
Phys. Lett. 1997, 270, 573.
(4) Hawker, C. J . Acc. Chem. Res. 1997, 30, 373.
S0022-3263(97)01820-3 CCC: $15.00 © 1998 American Chemical Society
Published on Web 02/07/1998

1556 J . Org. Chem., Vol. 63, No. 5, 1998
Miura et al.
Ch a r t 1
Sch em e 1
4-nitro-2,6-diphenylphenylaminyls (7), and N-[(2,4-di-
ch lor op h en yl)t h io]-4-ch lor o-2,6-d ip h en ylp h en yl-
aminyls (8) (Chart 1). The structures show that the
present thioaminyls have an electron-withdrawing sub-
stituent such as ethoxycarbonyl, acetyl, cyano, nitro, or
chloro at the anilino para position. If these radicals are
sufficiently stable to be isolated, a variety of isolable
stable thioaminyl radicals including di- and triradicals
can be prepared by using the functional groups. Herein
we report generation, stabilities, ESR spectra, isolation,
X-ray crystallographic analyses, and magnetic behavior
of 4-6.
of the 4-substituted 2,6-diarylanilines with arenesulfenyl
chlorides in dry ether or anhydrous THF in the presence
of Et3N gave 9 in 26-54%, 10 in 48-58%, 11 in 54-90%,
12 in 8%, and 13 in 55% yields, after column chromato-
graphic separation and subsequent crystallization.12
Although precursors 9e-h , 10, 11, 12, and 13 could
be readily purified by recrystallization from the appropri-
ate solvents, crystallization of 9a -d were unsuccessful,
giving a noncrystalline powder or viscous solid containing
small amounts of impurities. This is probably due to the
presence of a flexible ethyl ester group. We were
therefore forced to use the crude precursors in the next
oxidation step without any further purification as de-
scribed below. The analytical samples of 9a -d were
obtained by the preparative GPC purification and sub-
sequent crystallization.
Gen er a tion of 4-8 a n d Th eir ESR Sp ectr a . Oxi-
dation of 9-13 was carried out in benzene with PbO2.
When the ethoxycarbonyl, acetyl, and cyano substituted
precursors 9-11 were treated with PbO2, the solution
immediately turned dark blue (4a ,c-e,g-h , 6) or dark
green (4b,f, 5) and gave an intense EPR signal due to 4,
5, or 6. The characteristic dark blue or dark green colors
were constant at room temperature over a long period
without decomposition, even in the presence of atmo-
spheric oxygen, indicating that the generated thioaminyls
are quite persistent and oxygen-insensitive radicals. On
Resu lts a n d Discu ssion
P r ep a r a tion of P r ecu r sor s 9-13. The correspond-
ing precursors of 4-7, N-(arylthio)-4-(ethoxycarbonyl)-
2,6-diarylanilines (9), N-(arylthio)-4-acetyl-2,6-diaryla-
nilines (10), N-(arylthio)-4-cyano-2,6-diarylanilines (11),
N-[(2,4-dichlorophenyl)thio]-4-nitro-2,6-diphenylaniline
(12), and N-[(2,4-dichlorophenyl)thio]-4-chloro-2,6-di-
phenylaniline (13) were prepared according to Scheme
1. Thus, treatment of 4-(ethoxycarbonyl)aniline, 4-acetyl-
aniline, 4-cyanoaniline, or 4-chloroaniline with benzyl-
trimethylammomium tribromide (BTMA‚Br3) in CH2Cl2-
MeOH in the presence of CaCO3 gave 4-(ethoxycarbonyl)-
2,6-dibromoaniline in 80%, 4-acetyl-2,6-dibromoanilione
in 83%, 4-cyano-2,6-dibromoaniline in 81%, and 4-chloro-
2,6-dibromoaniline in 93% yields,10 respectively. 4-Nitro-
2,6-dibromoaniline was commercially available. The
palladium-catalyzed cross-coupling reaction of the dibro-
moanilines with arylboronic acid yielded 4-(ethoxycar-
bonyl)-2,6-diarylanilines in 87-90%, 4-acetyl-2,6-di-
arylanilines in 60-72%, 4-cyano-2,6-diphenylaniline in
80, 4-nitro-2,6-diphenylaniline in 95%, and 4-chloro-2,6-
diphenylaniline in 73% yield,11 respectively. The reaction
(10) Kajigaeshi, S.; Kakinami, T.; Inoue, K.; Kondo, M.; Nakamura,
H.; Fujikawa, M.; Okamoto, T. Bull. Chem. Soc. J pn. 1988, 61, 597.
(11) (a) Miura, Y.; Oka, H.; Momoki, M. Synthesis 1995, 1419. (b)
Miyaura, N.; Suzuki, A. Chem. Rev. 1995, 95, 2457.
(12) The yields of 9a -d were determined after column chromato-
graphic separation without recrystallizing.

Stable Thioaminyl Radicals Having Functional Groups
J . Org. Chem., Vol. 63, No. 5, 1998 1557
Ta ble 1. ESR Sp ectr a l Da ta for 4-8 in Ben zen e a t 20 °C
radical
aN/mT
aH/mTa
g
4a b
4be
4cb
4d b
4eb
4fe
0.893
0.893
0.891
0.888
0.890
0.891
0.891
0.886
0.889
0.881
0.876
0.876
0.877
0.876
0.875
0.873
0.914
0.128 (2H),c 0.093 (3H)d
2.0059
2.0059
2.0060
2.0059
2.0060
2.0060
2.0061
2.0059
2.0060
2.0060
2.0061
2.0062
2.0061
2.0060
2.0057
0.132 (2H),c 0.097 (1H)f
0.125 (2H),c 0.091 (3H)d
0.128 (2H),c 0.091 (3H)d
4gb
4h b
4ib,g
5be
5cb
5gb
5ib,h
6cb,i
6d b,j
7e
0.133 (2H),c 0.096 (1H)f
0.125 (2H),c 0.093 (3H)d
0.132 (2H),c 0.098 (1H)f
0.132 (2H),c 0.097 (1H)f
0.132 (2H),c 0.097 (1H)f
0.132 (2H),c 0.097 (1H)f
0.130 (2H),c 0.099 (1H)f
0.128 (2H),c 0.093 (3H)d
8e
a
The number in parentheses refers to the number of magneti-
b
cally equivalent protons. The hyperfine coupling (hfc) constants
are determined by computer simulation. c The hfc constants due
d
to the anilino meta protons. The hfc constants due to the
phenylthiyl ortho and para protons. e Hfc constants due to protons
are not determined because of the poor resolution. f The hfc
constants due to the phenylthiyl ortho protons. a33 ) 0.55 mT,
g
S
and a13 (1C) ) 1.02 mT. a33 ) 0.54 mT, and a13 (1C) ) 1.01
h
C
S
C
i
j
mT. aN (CN) ) 0.065 mT. aN (CN) ) 0.066 mT.
F igu r e 1. ESR spectra of 5c in benzene at 20 °C. (a) The
experimental ESR spectrum; (b) computer simulation.
the other hand, the nitro- and chloro-substituted precur-
sors, 12 and 13, yielded unstable radicals on oxidation.
When 12 or 13 were treated with PbO2, the light yellow
(12) or colorless solution (13) immediately turned green
(7) or blue (8), but the characteristic green or blue color
soon faded and finally turned dark red. From this color
change the corresponding radicals, 7 and 8, were shown
to be unstable.
The ESR spectra of 4-8 were recorded at room
temperature (20 °C) using benzene as the solvent.
Although 4, 5, and 6 gave intense and clean ESR spectra,
those of 7 and 8 were very weak, and only ESR spectra
with a low S/N ratio were obtained. A typical ESR
spectrum is shown in Figure 1 and the ESR parameters
are summarized in Table 1.
All the ESR spectra were split into a 1:1:1 triplet with
nearly identical hyperfine coupling constants in the range
0.873-0.914 mT. In the cases of 4b, 4f, 5b, 7, and 8 no
further hyperfine splittings due to protons were observed.
On the other hand, 4c, 4g, 5c, 5g showed hyperfine
splittings due to the anilino meta and phenylthiyl ortho
protons, giving spectra consisting of a 1:1:1 triplet of
1:3:3:1 quartets (see: Figure 1), and 4a , 4d , 4e, 4h
showed hyperfine splittings due to the anilino meta and
phenylthiyl ortho and para protons, giving spectra con-
sisting of a 1:1:1 triplet of 1:5:10:10:5:1 sextets. In the
ESR spectra of 6c and 6d the 1:1:1 triplets were split
into quintets (not quartets) (6c) or septets (not sextets)
(6d ), suggesting an appearance of the hyperfine splitting
due to the cyano nitrogen. Although a 1:1:1 hyperfine
splitting due to the cyano nitrogen was not clearly
observed, the ESR spectra obtained were well recon-
structed by computer simulation by adding the hyperfine
splitting of 0.065 (6c) or 0.066 mT (6d ) due to the cyano
nitrogen.
F igu r e 2. ESR spectrum of 5i in benzene at 20 °C. Both wings
are recorded at high gain (100 times). Satellite lines due to
33S (a and b, MN ) +1, MS ) +3/2; g and h, MN ) -1, MS
-3/2) and 13C (c and d, MN ) +1, MC ) +1/2; MN ) -1, MC
-1/2) were observed.
)
)
Ch a r t 2
as for the corresponding nondeuterated compounds (Chart
2). The ESR spectrum of 4i is shown in Figure 2. As
had been expected, the deuterated radicals gave a well
resolved ESR spectrum consisting of a 1:1:1 triplet of
1:3:3:1 quartets, showing that the quartet hyperfine
splitting is certainly due to the anilino meta and phe-
nylthiyl ortho protons. On the basis of the above result,
To confirm the assignments for the proton hyperfine
splittings, 2- and 6-phenyl deuterated thioaminyls, 4i and
5i, were prepared from 4-(ethoxycarbonyl)- or 4-acetyl-
2,6-di(phenyl-d5)aniline according to the same procedure

1558 J . Org. Chem., Vol. 63, No. 5, 1998
Miura et al.
Ta ble 2. P r od u ct An a lyses for Decom p osition of 7 a n d 8
it can be said that the 2- and 6-phenyl groups give no
hyperfine splitting (only broaden the line width).
products from 7a
yieldb/%c
products from 8d
yieldb/%c
When the ESR spectra of 4i and 5i were recording at
a high gain (100 times the parent spectrum), satellite
lines due to 33S and 13C at the natural abundance (33S
0.76, 13C 1.11%) could be observed in the both wings of
the parent spectrum. From the spectrum a and a
were determined to be 0.55 and 1.02 mT (4i) and 0.54
and 1.01 mT (5i), respectively. Assignments of the
satellite lines observed were made by the intensity ratio
of the satellite lines to the parent spectrum. The
observed intensities are 0.12-0.13 (33S) and 0.56-0.64%
(13C), which are in good agreement with the theoretical
values (0.19% for 33S and 0.56% for 13C).
disulfidee
14
77
58
disulfidee
15
85
87
a
100 mg (0.214 mmol) of 12 was oxidized and 16 mg of
b
unreacted 12 was recovered. Yields after column chromatogra-
phy. c Percent yields based on the reacted 12 or 13. 200 mg (0.438
d
33S
13C
mmol) of 13 was oxidized, and 91 mg of unreacted 13 was
recovered. e 2,4-Dichlorophenyl disulfide.
Sch em e 2
Isola tion of 4, 5, a n d 6. As mentioned above,
thioaminyls 4, 5, and 6 persist without decomposition.
Temperature dependence of the ESR signal intensity for
these radicals showed that the radicals exist in solution
as individual radicals (and do not dimerize). We there-
fore decided to isolate thioaminyl radicals.
Isolation of 4, 5, and 6 was accomplished by the
following procedures; a benzene solution of the corre-
sponding precursors (9-11) was treated with PbO2, and,
after filtration, the solvent was removed by freeze-drying
method. The resulting dark blue or dark green crystal-
line residue was crystallized from MeOH (4c, 4d ),
EtOH-ethyl acetate (4a , 4b, 4e, 4f, 4g, 4h , 5b, 5c, 5g),
hexane (6c), or hexanes-ethyl acetate (6d ) to give dark
blue or dark green needles or prisms in 16-52% yields.13
In the IR spectra no absorption peak due to the
stretching vibration of the NH bond (3300-3370 cm-1
)
was observed. The elemental analyses gave satisfactory
agreements with the calculations. The radical purities
determined by ESR using 3,4-dihydro-2,4,6-triphenyl-2H-
1,2,4,5-tetrazin-1-yl (1,3,5-triphenylverdazyl)14 as the
reference was >95%. The magnetic susceptibility mea-
surements of the radical crystals showed ∼100% purities,
as described below.
8.28 for 14, and 6.32-7.46 ppm for 15) and suggested no
peaks due to NH. No presence of NH was further
confirmed by the IR spectra. The mass spectra gave a
peak at m/z 707 (14) or 698 (15) as the molecular ion.
The mass number 707 corresponds to 2 × 7 - (2,4-
Cl2C6H3S + NO2) and the mass number 698 corresponds
to 2 × 8 - (2,4-Cl2C6H3S + Cl). On the basis of the above
1H NMR, IR, and mass spectroscopic results, their
structures were determined to be 14 and 15, respectively.
The elemental analyses also gave satisfactory results.
Compounds 14 and 15 exist in solution as a mixture of
syn- and anti-isomers. The results of the product analy-
ses are summarized in Table 2.
A plausible mechanism for the decomposition is shown
in Scheme 2. The first step is the N-C coupling between
two thioaminyl radicals to give 16.15 Elimination of a
2,4-dichlorophenylthiyl radical and X (X: NO2, Cl) from
16 gives 14 or 15, along with 2,4-diclorophenyl disulfide.
Consequently, the instabilities of 7 and 8 can be ascribed
to the insufficient protection of the para position by the
NO2 or Cl group which allows attack by another 7 or 8
radicals.
P r od u ct An a lysis for Decom p osition of 7 a n d 8.
In contrast to 4-6, radicals 7 and 8 are unstable, as
mentioned above. To understand their decomposition
mechanism, the product analysis for the decomposition
was carried out. Radicals 7 and 8 were generated by
oxidation of 12 or 13 with PbO2 in benzene. After
filtration, the resulting dark red mixture obtained was
inspected by TLC. The TLC analyses showed formation
of two main products (one is red and the other is colorless)
and a few minor products, along with the unreacted
precursor. The two main products, as well as the
precursors, were isolated by column chromatograpy. The
first eluted colorless product was identified as 2,4-
dichlorophenyl disulfide on the basis of the IR and 1H
NMR spectra. The second eluted red products were the
unknown compounds, and their structures were eluci-
1
dated on the basis of the H NMR, IR, and mass spectra.
1
The H NMR spectra were complex and relatively broad
because there are many aromatic protons and the NMR
samples were a mixture of syn- and anti-isomers as
mentioned below. However, the 1H NMR spectra clearly
indicated that all peaks are in the aromatic region (6.22-
X-r a y Cr ysta llogr a p h ic An a lysis. Although most of
the thioaminyl radical crystals obtained were micron-
eedles or microprisms unsuitable for the X-ray crystal-
(15) (a) Miura, Y.; Yamamoto, A.; Kinoshita, M. Bull. Chem. Soc.
J pn. 1981, 54, 3215. (b) Benati, L.; Montevecchi, P. C.; Spagnolo, P.
J . Chem. Soc., Perkin Trans. 1 1982, 3049. (c) Balboni, C.; Benati, L.;
Montevecchi, P. C.; Spagnolo, P. J . Chem. Soc., Perkin Trans 1 1983,
2111.
(13) Fortunately, pure radical crystals were successfully obtained
even from the crude precursors of 9a -d in 16-26% yields after
recrystallization.
(14) Kuhn, R.; Trischmann, T. Monatsh. Chem. 1964, 95, 457.

Stable Thioaminyl Radicals Having Functional Groups
J . Org. Chem., Vol. 63, No. 5, 1998 1559
Ta ble 3. Selected Bon d Len gth s a n d An gles a n d Tor sion
An gles of 5c a n d 6c
5c
Bond Lengths (Å)
Bond Angles (deg)
C1-N1
1.364(4)
1.619(3)
1.770(4)
C2-C1-N1
113.2(3)
128.1(3)
125.5(3)
98.7(2)
N1-S1
C6-C1-N1
C1-N1-S1
N1-S1-C19
S1-C19
Torsion Angles (deg)
178.4(3) N1-S1-C19-C24
S1-N1-C1-C2
S1-N1-C1-C6
8.1(4)
0.4(6) N1-S1-C19-C20 -172.2(3)
C1-N1-S1-C19 -179.1(3) O1-C25-C4-C3
-3.8(6)
6c
Bond Lengths (Å)
Bond Angles (deg)
C1-N1
1.341(7)
1.634(4)
1.767(6)
C2-C1-N1
C6-C1-N1
C1-N1-S1
N1-S1-C19
115.1(5)
N1-S1
126.8(5)
123.7(4)
100.9(3)
S1-C19
Torsion Angles (deg)
-177.4(4) N1-S1-C19-C24
6.7(9) N1-S1-C19-C20 -177.0(5)
179.4(5)
S1-N1-C1-C2
S1-N1-C1-C6
C1-N1-S1-C19
3.2(6)
dihedral angle between the benzene rings A and B is 62.1
(5c) or 45.9° (6c), and that between the benzene rings A
and C is 77.1 (5c) or 84.2° (6c), indicating that there are
serious steric congestions around the nitrogen radical
center surrounded by the two phenyl groups. Conse-
quently, it can be concluded that the π-framework
consisting of the A and D benzene rings and the N and
S atoms is nearly planar, but the B and C benzene rings
are significantly twisted from the coplane in both radi-
cals. The X-ray crystallographic results are in good
agreement with the ESR results which show that the
unpaired electron is extensively delocalized onto the
anilino benzene ring and phenylthiyl group.
F igu r e 3. ORTEP drawing of 5c.
Upon comparison of the X-ray crystallographic data
with 1-3,1,5 it is obvious that the bond lengths and bond
angles are nearly identical, but the planarity of the Ph-
N-S-Ph π-frameworks is somewhat different from those
for 1-3. As shown by the C-C-N-S, C-N-S-C, and
N-S-C-C torsion angles (Table 4), 5c and 6c have the
most planar π-frameworks, and 2 and 3 have the less
planar π-frameworks. Consequently, the planarity of the
Ph-N-S-Ph π-framework is in the order 4 ≈ 5 > 1 > 2
≈ 3.
UV-vis Sp ectr a of Th ioa m in yl Ra d ica ls. Aminyls
4, 5, and 6 are characterized by a blue (4a ,c-e,g-h , 6)
or green color (4b,f, 5) in solution. The UV-vis spectra
of 4f and the corresponding precursor, 9f, are shown in
Figure 5. The UV-vis spectral data for 4-6 are sum-
marized in Table 5.
F igu r e 4. ORTEP drawing of 6c.
lographic study, N-[(2,4-dichlorophenyl)thio]-4-acetyl-2,6-
diphenylphenylaminyl (5c) and N-[(2,4-dichlorophenyl)-
thio]-4-cyano-2,6-diphenylphenylaminyl (6c) gave suf-
ficiently large prisms, allowing X-ray crystallographic
analyses. The ORTEP drawings of 5c and 6c are
illustrated in Figures 3 and 4, and the X-ray crystal-
lographic data are shown in the Experimental Section.
The selected bond lengths, bond angles, and torsion
angles are summarized in Table 3.
The X-ray crystallographic studies for 5c and 6c gave
the following structural features: In both radicals the
benzene rings A and D and the N and S atoms (Ph-N-
S-Ph plane) are almost in the same plane, as indicated
by the torsion angles shown in Table 3. The carbonyl
group is also planar to this coplane (the torsion angle of
O1-C25-C4-C3 is -3.8°). On the other hand, the
Aminyl 4f shows absorption peaks at 627 (ꢀ 5420), 473
(6790), 412 (19000), and 307 nm (10000), while 5f absorbs
only at 337 nm (ꢀ 13800). Since any precursor has no
strong absorption in the visible region, the radical
concentrations can be easily determined by the charac-
teristic absorptions in the visible region.
Sp in Den sity Distr ibu tion . To discuss quantita-
tively the spin density distribution in the present radi-
cals, MO calculations for 5 were performed by the
McLachlan-perturbation method using the following
parameters: RN ) R + 0.6â, RS ) R + â, RO ) R + 2.0â,
RC25 ) R + 0.1â, âCN ) 1.1â, âNS ) 0.7â, âCS ) 0.7â, âC4-C25

1560 J . Org. Chem., Vol. 63, No. 5, 1998
Ta ble 4. Com p a r ison of Tor sion An gles of 5c w ith 1a a n d 2a a
Miura et al.
1a
2a
5c
C2-C1-N-S
C6-C1-N-S
C1-N-S-C25
N-S-C25-C26
N-S-C25-C30
-170.4
14.6
C2-C1-N-S
C6-C1-N-S
C1-N-S-C19
N-S-C19-C20
N-S-C19-C24
22.4
-158.1
175.3
2.4
-178.7
C2-C1-N-S
C6-C1-N-S
C1-N-S-C19
N-S-C19-C24
N-S-C19-C20
178.4
0.4
-174.7
-179.1
2.2
8.1
179.8
-172.2
a
The torsion angles are given in degrees.
Ta ble 6. Exp er im en ta l a n d Ca lcu la ted Hyp er fin e
Cou p lin g Con sta n ts for 5
obsd
calcd
spin density
calcd
position
hfc consta
hfc consta,b
N
S
0.876
0.55c
0.405
0.211
0.891
0.485
1
2
3
4
5
6
7
-0.035
F igu r e 5. UV-vis spectra of 4b and 9b in benzene: (a) 4b,
0.123 mM; (b) 9b, 1.22 mM.
0.118
0.132d
0.132d
-0.023
0.106
-0.023
0.119
-0.001
0.001
-0.000
0.001
-0.000
0.000
-0.000
0.000
-0.012
0.026
-0.008
0.024
0.062d
0.062d
Ta ble 5. UV-Vis Sp ectr a l Da ta of 4, 5, a n d 6 in Ben zen e
radical
λ )
max/nm (ꢀ/L mol-1 cm-1
4a
4b
4c
4d
4e
4f
4g
4h
5b
5c
372 (14500), 408 (10600 sh), 546 (3030sh), 617 (4820)
311 (10200), 413 (19100), 480 (7610), 623 (5340)
306 (6190 sh), 383 (18500), 559 (4010 sh), 634 (6430)
381 (17400), 554 (3290 sh), 618 (5190)
8, 12
9, 11
10
13
374 (14500), 545 (3190 sh), 621 (5000)
14, 18
15, 17
16
307 (10000), 412 (19000), 473 (6790), 627 (5420)
308 (5820 sh), 383 (17200), 426 (6930 sh), 640 (5980)
381 (19100), 556 (3710 sh), 623 (5720)
313 (8830), 425 (20100), 477 (6310), 633 (4980)
315 (6360 sh), 390 (16800), 437 (10700), 554 (3190 sh),
644 (6160)
19
20, 24
21, 23
22
25
O
0.097d
-0.070d
-0.065d
0.097d,e
5g
6c
6d
389 (14500), 439 (8310), 550 (2550 sh), 650 (5140)
381 (12100), 425 (4040 sh), 554 (2560 sh), 644 (4470)
313 (4330 sh), 378 (14000), 543 (2600 sh), 628 (4540)
0.051
0.022
a
b
The hyperfine coupling constants are given in mT. Derived
from the hfc constants using the equation, aX ) QXFX, where QH
) 0.7â, âC25-O ) 1.37â, and λ ) 0.7.1,5,16 The resonance
integrals between C2-C7 and C6-C13 are changed to
0.22â () cos2 62.9°) and 0.05â () cos2 77.1°), respectively,
on the basis of the X-ray crystallographic results of 5c.
The results of the calculations are listed in Table 6.
As found in Table 6, the calculations are in good
agreement with the experimental results, and the fol-
lowing conclusions are withdrawn from Table 6. First,
the unpaired electron is extensively delocalized over the
anilino and phenylthiyl groups. Second, a small amount
of the spin densities appears on the acetyl group. Third,
the delocalization of the unpaired electron onto the 2-
and 6-phenyl groups is negligibly small due to the
d
) -2.7, QN ) 2.2, and Q ) 2.3 mT. c The value for 5i. The hfc
33
S
constant for the proton attached to the carbon. e The value for 5g.
significant twisting. Although delocalization of the un-
paired electron onto the carbonyl group cannot be ex-
perimentally confirmed until the carbonyl carbon or
oxygen is labeled by 13C or 17O, a small delocalization of
the unpaired electron onto the cyano group is observed
in the ESR spectra of 6, as mentioned above.
Com p a r ison of ESR P a r a m eter s w ith Str u ctu r -
a lly Rela ted Ra d ica ls. Thioaminyls 4-6 are structur-
ally close to 1-3.5-7 The hyperfine coupling constants
and g values for 4-6 are compared with those for 1-3
and 17 in Table 7. Radical 17 is a structurally basic
radical for 1-8.17 Although there are no large differences
in the hfc constants and g values between 4-6 and 1-3
(16) Miura, Y.; Asada, H.; Kinoshita, M.; Ohta, K. J . Phys. Chem.
1983, 87, 3450.

Stable Thioaminyl Radicals Having Functional Groups
J . Org. Chem., Vol. 63, No. 5, 1998 1561
Sch em e 3
Ta ble 7. Com p a r ison of th e ESR P a r a m eter s of 4-6
w ith Str u ctu r a lly Rela ted Th ioa m in yl Ra d ica ls
b
33S
radical
aN
aH
a
g
1
2
3
17
4
5
0.890-0.896 0.133-0.134 0.51 2.0054-2.0059
0.921-0.936 0.126-0.130 0.51 2.0054-2.0060
0.932-0.953 0.127-0.138
0.959 0.126
2.0054-2.0058
2.0059
0.886-0.893 0.125-0.133 0.55 2.0059-2.0061
0.876-0.881 0.132
0.875-0.876 0.128-0.130
0.54 2.0060-2.0062
2.0057-2.0060
6
a
b
The hfc constants are given in mT. The hfc constants due to
the anilino meta protons.
F igu r e 6. øT vs T plots of 4f.
and 17, there are some small differences. First, the aN
values for 4-6 are somewhat smaller than those for 1-3
and 17. Second, the a33 values for 4-6 are 0.03-0.04
S
mT larger than those for 1 and 2. Thioaminyl radicals
4-6, as well as 1-3 and 17, can be well represented by
the canonical structures A and B (Scheme 3). If the
relative importance of A is reduced and the relative
importance of B is enhanced, aN values will be reduced
and a33 will be increased, with an increase in the g
S
values.18 Since 4-6 bear an electron-withdrawing sub-
stituent at the para position of the anilino group, the
relative importance of canonical structure B will be
increased. The reduction in aN and increases in a33S and
g can therefore be accounted for in terms of an increase
in the relative importance of canonical structure B.
Ma gn etic Su scep tibility Mea su r em en ts. The mag-
netic susceptibility (ø) measurements were carried out
for five thioaminyl radicals using polycrystalline samples
with a SQUID magnetometer in the temperature range
1.8-300 K. The diamagnetic components were sub-
tracted by the estimation based on Pascal’s sum rule for
the atomic contribution and the structural correction. The
purities of the radicals used were shown to be ∼100% by
the magnetic susceptibility measurements.
Figure 6 shows ømolT vs T plots for 4f (ømol: molar
magnetic susceptibility). Although ømolT is constant
above 100 K, it sharply increases below 100 K with the
lowering of temperature, indicating the spin-exchange
interaction between the unpaired electron spins is fer-
romagnetic. The magnetic behavior was analyzed in
terms of the regular one-dimensional Heisenberg model19
(eq 1) with 2J /kB ) 16.0 K.
F igu r e 7. øT vs T plots of 6c.
The observed ømolT vs T plots were analyzed in terms of
the alternating linear chain model (eq 2)20 with 2J /kB
)
-194.6 K and R ) 0.09. An origin of the strong antifer-
romagnetic interaction can be found in its crystal struc-
ture which indicates that 6c forms a dimer having a large
SOMO-SOMO overlap in the radical crystal.
H ) -2J [S S + RS2iS2i+1
]
(2)
∑
2i 2i
In the cases of 4h , 5c, and 5g the magnetic exchange
interactions were also antiferromagnetic. The ømolT vs
T plots for 5c were analyzed with the singlet-triplet
model with 2J /kB ) -15.6 K, and for 4h and 5g the
magnitudes of the magnetic exchange interactions were
estimated by the Weiss temperature θ obtained from the
1/ømol vs T plots because the magnetic exchange interac-
tions are very weak (4h , -5.0 K; 5g, -0.6 K).
Con clu sion s. In the present study 4-ethoxycarbonyl
(4), 4-acetyl (5), 4-cyano (6), 4-nitro (7), and 4-chloro (8)
substituted N-(arylthio)-2,6-diarylphenylaminyl radicals
were prepared. Although the 4-nitro and 4-chloro sub-
stituted radicals are unstable and immediately decom-
pose, 4-ethoxycarbonyl, 4-acetyl, and 4-cyano substi-
tuted radicals are very stable and could be isolated as
H ) -2J S S
(1)
∑
i
j
In contrast, 6c showed a strong antiferomagnetic
coupling between the unpaired electron spins. As found
in Figure 7, ømolT is already reduced at room temperature
and, with lowering of temperature, drastically reduced.
(17) Miura, Y.; Kinoshita, M. Bull. Chem. Soc. J pn. 1977, 50, 1142.
(18) The spin-orbit coupling parameter is 382 cm-1; McClure, D.
S. J . Chem. Phys. 1949, 17, 905.
(20) (a) Duffy, W., J r.; Barry, K. P. Phys. Rev. 1968, 165, 647. (b)
Hall, J . W.; March, W.; Weller, R. R.; Hatfield, W. E. Inorg. Chem.
1981, 20, 1033.
(19) Bonner, J . C.; Fisher, M. E. Phys. Rev. 1964, A135, 640.

1562 J . Org. Chem., Vol. 63, No. 5, 1998
Miura et al.
4-(Eth oxycar bon yl)-2,6-diph en ylan ilin e: colorless needles
(hexane); yield 90%; mp 96-97 °C; IR (KBr) 3470 and 3360
pure radical crystals. The product analyses for the
decomposition of the 4-nitro and 4-chloro substituted
radicals indicated that the decomposition proceeds via
formation of the C-N coupled dimer. The X-ray crystal-
lographic analyses for 5c and 6c exhibited that the Ph-
N-S-Ph framework is nearly planar, while the 2- and
6-phenyl groups are significantly twisted from the co-
plane. The ESR results for the thioaminyl radicals
indicated that the unpaired electron is extensively delo-
calized over the anilino and phenylthiyl benzene rings.
The magnetic susceptibility measurements showed that,
although four radicals couple antiferromagnetically with
2J /kB ) -15.6 to -194.6 K or θ ) -0.6 to -5.0 K, one
radical couples ferromagnetically with 2J /kB ) +16.0 K.
The detailed magnetic behavior of the ferromagnetic
radical in the low-temperature region below 2 K is now
under investigation.
1
(NH2) and 1700 cm-1 (CdO); H NMR (CDCl3) δ 1.35 (t, J )
7.3 Hz, 3 H), 4.26 (s, 2 H), 4.32 (q, J ) 7.3 Hz, 2 H), 7.36-7.51
(m, 10 H), 7.83 (s, 2 H). Anal. Calcd for C21H19NO2: C, 79.47;
H, 6.03; N, 4.41. Found: 79.41; H, 6.08; N, 4.37.
4-(Eth oxycar bon yl)-2,6-bis(4-ch lor oph en yl)an ilin e: col-
orless needles (EtOH); yield 87%; mp 155-156 °C; IR (KBr)
3470 and 3380 (NH2) and 1720 cm-1 (CdO); 1H NMR (CDCl3)
δ 1.35 (t, J ) 7.3 Hz, 3 H), 4.18 (s, 2 H), 4.33 (q, J ) 7.3 Hz,
2 H), 7.41-7.47 (m, 8 H), 7.79 (s, 2 H). Anal. Calcd for
C
21H17Cl2NO2: C, 65.30; H, 4.44; N, 3.63. Found: C, 65.17;
H, 4.49; N, 3.61.
4-(Eth oxyca r bon yl)-2,6-d i(p h en yl-d 5)a n ilin e: colorless
needles (hexane); yield 88%; mp 98-99 °C; IR (KBr) 3470 and
1
3380 (NH), 1700 cm-1 (CdO); H NMR (CDCl3) δ 1.35 (t, J )
7.3 Hz, 3 H), 4.18 (s, 2 H), 4.33 (q, J ) 7.3 Hz, 2 H), 7.83 (s, 2
H).
4-Acetyl-2,6-d ip h en yla n ilin e: colorless prisms (hexanes-
EtOH); yield 72%; mp 138-139 °C; IR (KBr) 3470 and 3370
(NH2) and 1660 cm-1 (CdO); 1H NMR (CDCl3) δ 2.53 (s, 3 H),
4.35 (s, 2 H), 7.35-7.49 (m, 10 H), 7.76 (s, 2 H). Anal. Calcd
for C20H17NO: C, 83.59; H, 5.96; N, 4.88. Found: 83.44; H,
5.96; N, 4.80.
Exp er im en ta l Section
Preparative GPC separation was performed with a LC-908
recycling preparative HPLC instrument (J apan Analytical
Industry Co. LTD). IR spectra were run on a J ASCO FT/IR-
230 spectrophotometer. UV-vis spectra were measured with
a Shimadzu UV-2200 spectrophotometer. 1H NMR spectra,21
mass spectra,21 and ESR spectra1 were taken as previously
reported. Magnetic susceptibility measurements were per-
formed in the temperature range 1.8-300 K on a Quantam-
Design MPMS2 SQUID magnetometer. Diamagnetic contri-
butions were estimated by Pascal’s sum rule.
4-(Ethoxycarbonyl)aniline, 4-acetylaniline, 4-cyanoaniline,
4-chloroaniline, and 2,6-dibromo-4-nitroaniline were com-
mercially available. Phenylboronic acid, 4-chlorophenylboronic
acid, and phenylboronic-d5 acid were obtained according to the
reported methods.1 4-(Ethoxycarbonyl)-2,6-dibromoaniline,
4-acetyl-2,6-dibromoaniline, 2,6-dibromo-4-cyanoaniline, and
4-chloro-2,6-dibromoaniline were obtained by treating 40 mmol
of the anilines with 39.0 g (100 mmol) of benzyltrimethyl-
ammonium tribromide (BTMA‚Br3) in CH2Cl2 (400 mL)-
MeOH (160 mL) at room temperature for 3 h in the presence
of 11.2 g of CaCO3 in the usual manner.10 Crystallization gave
4-(ethoxycarbonyl)-2,6-dibromoaniline as colorless needles
(EtOH) with mp 107-108 °C in 80% yield, 4-acetyl-2,6-
dibromoaniline as colorless fine prisms (EtOH) with mp 168-
169 °C in 83% yield, 4-cyano-2,6-dibromoaniline as colorless
needles (EtOH) with mp 121-122 °C in 81% yield, and
4-chloro-2,6-dibromoaniline as colorless needles (hexane) with
mp 93-95 °C in 93% yield, respectively. Silica gel column
chromatography was carried out on Wako gel C-200, and
alumina column chromatography on Merck aluminum oxide
90.
A Gen er a l P r oced u r e for P r ep a r a tion of 4-Su bstitu ted
2,6-Dia r yla n ilin es. A mixture of 20 mmol of 4-substituted
(ethoxycarbonyl, acetyl, cyano, nitro, and chloro) 2,6-dibro-
moaniline, 60 mmol of arylboronic acid, 2.78 g (2.41 mmol) of
(PPh3)4Pd, 17.0 g of Na2CO3 in benzene (200)-EtOH (30)-
water (80 mL) (for 4-(ethoxycarbonyl)-, 4-acetyl-, 4-cyano-, and
4-chloro-2,6-dibromoanilines) or in dimethoxyethane (300)-
EtOH (30)-water (80 mL) (for 4-nitro-2,6-dibromoaniline) was
refluxed for 14 h under a nitrogen atmosphere.11 The organic
layer was extracted with benzene or CHCl3, and the combined
extracts were washed with brine. After drying (MgSO4), the
solvent was evaporated and the residue chromatographed on
silica gel with benzene (4-(ethoxycarbonyl)-2,6-diarylaniline,
4-nitro-2,6-diphenylaniline), 1:10 ethyl acetate-benzene (4-
acetyl-2,6-diarylaniline), or 1:3 benzene-hexane (4-chloro-2,6-
diphenylaniline), or on alumina with CH2Cl2 (4-cyano-2,6-
diphenylaniline). Crystallization from the appropriate solvents
gave pure 4-substituted 2,6-diarylanilines.
4-Acetyl-2,6-bis(4-ch lor oph en yl)an ilin e: colorless prisms
(EtOH-ethyl acetate); yield 60%; mp 203-204 °C; IR (KBr)
3460 and 3350 (NH2) and 1660 cm-1 (CdO); 1H NMR (CDCl3)
δ 2.53 (s, 3 H), 4.25 (s, 2 H), 7.42 (d, J ) 8.8 Hz, 4 H), 7.47 (d,
J ) 8.8 Hz, 4 H), 7.76 (s, 2 H). Anal. Calcd for C20H15Cl2NO:
C, 67.43; H, 4.24; N, 3.93. Found: C, 67.49; H, 4.29; N, 3.91.
4-Acetyl-2,6-d i(p h en yl-d 5)a n ilin e: colorless prisms (hex-
anes-EtOH); yield 67%; mp 140-141 °C; IR (KBr) 3470 and
1
3370 (NH2), 1660 cm-1 (CdO); H NMR (CDCl3) δ 2.54 (s, 3
H); 4.27 (s, 2 H), 7.77 (s, 2 H).
4-Cyan o-2,6-diph en ylan ilin e: light yellow prisms (EtOH);
yield 80%; mp 152-154 °C; IR (KBr) 3480 and 3390 (NH2),
2210 cm-1 (CN); 1H NMR (CDCl3) δ 4.35 (s, 2H), 7.38 (s, 2 H),
7.40-7.51 (m, 10 H). Anal. Calcd for C19H14N2: C, 84.41; H,
5.23; N, 10.36. Found: C, 84.39; H, 5.12; N, 10.32.
4-Nitr o-2,6-d ip h en yla n ilin e: light yellow plates (hexane-
benzene); yield 95% yield; mp 167-168 °C; IR (KBr) 3480 and
1
3380 cm-1 (NH2); H NMR (CDCl3) δ 4.59 (s, 2 H), 7.41-7.53
(m, 10 H), 8.05 (s, 2 H). Anal. Calcd for C18H14N2O2: C, 74.46;
H, 4.86; N, 9.65. Found: C, 74.78; H, 4.89; N, 9.58.
4-Ch lor o-2,6-d ip h en yla n ilin e: colorless prisms (hexane);
yield 73%; mp 79-81 °C; IR (KBr) 3460 and 3350 cm-1 (NH2);
1H NMR (CDCl3) δ 3.81 (s, 2H), 7.11 (s, 2 H), 7.46-7.50 (m,
10 H). Anal. Calcd for C18H14ClN: C, 77.27; H, 5.05; N, 5.01.
Found: C, 77.28; H, 4.95; N, 4.96.
Gen er a l P r oced u r e for P r ep a r a tion of 9-13. To a
stirred solution of 6.30 mmol of 4-substituted 2,6-diarylanilines
and 1.46 g (2.0 mL) of Et3N in 200 mL of dry ether (or
anhydrous THF) was added at 0 °C a solution of 7.8 mmol of
arenesulfenyl chloride in 20 mL of dry ether (or anhydrous
THF). After being stirred for 2 h at 0 °C, the mixture was
filtered and evaporated under reduced pressure, and the
residue was chromatographed on alumina with benzene (10b,
10c, 10g, 10i), 2:1 (9e and 9f), 1:1 (9a -d , 9g-i, 11c, 11d , 12),
or 1: 5 benzene-hexane (13) as eluant. Compounds 9a -d
were used in the following oxidation step without further
purification. The analytical samples of 9a -d were obtained
by separation of almost pure parts with a preparative GPC
instrument using CHCl3 as eluant and subsequent recrystal-
lization from MeOH. The other compounds were purified by
recrystallization.
N -[(3-Nit r op h e n yl)t h io]-4-(e t h oxyca r b on yl)-2,6-d i-
p h en yla n ilin e (9a ): light yellow fine prisms (MeOH); yield
43%; mp 47-49 °C; IR (KBr) 3330 (NH), 1720 cm-1 (CdO);
1H NMR (CDCl3) δ 1.35 (t, J ) 7.3 Hz, 3 H), 4.34 (q, J ) 7.3
Hz, 2 H), 5.65 (s, 1 H), 7.02 (d, J ) 8.3 Hz, 1 H), 7.21 (t, J )
8.3 Hz, 1 H), 7.32-7.40 (m, 10 H), 7.63 (t, J ) 2.0 Hz, 1 H),
(21) Miura, Y.; Oka, H.; Yamano, E.; Morita, M. J . Org. Chem. 1997,
62, 1188.

Stable Thioaminyl Radicals Having Functional Groups
J . Org. Chem., Vol. 63, No. 5, 1998 1563
7.84 (dd, J ) 8.3 and 2.0 Hz, 1 H), 7.85 (s, 2 H). Anal. Calcd
for C27H22N2O4S: C, 68.92; H, 4.71; N, 5.95. Found: C, 69.45;
H, 4.92; N, 5.58.
2 H). Anal. Calcd for C26H20N2O3S: C, 70.89; H, 4.58; N, 6.36.
Found: C, 70.87; H, 4.61; N, 6.33.
N-[(2,4-Dich lor op h e n yl)t h io]-4-a ce t yl-2,6-d ip h e n yl-
a n ilin e (10c): colorless fine prisms (EtOH-benzene); yield
56%; mp 131-132 °C; IR (KBr) 3320 (NH), 1680 cm-1 (CdO);
1H NMR (CDCl3) δ 2.56 (s, 3 H), 5.55 (s, 1 H), 6.86 (d, J ) 8.3
Hz, 1 H), 7.00 (dd, J ) 8.3 and 2.0 Hz, 1 H), 7.08 (d, J ) 2.0
Hz, 1 H), 7.32-7.36 (m, 10 H), 7.77 (s, 2 H). Anal. Calcd for
N -[(4-Nit r op h e n yl)t h io]-4-(e t h oxyca r b on yl)-2,6-d i-
p h en yla n ilin e (9b): light yellow fine prisms (MeOH); yield
46%; mp 61-62 °C; IR (KBr) 3300 (NH), 1710 cm-1 (CdO);
1H NMR (CDCl3) δ 1.35 (t, J ) 7.3 Hz, 3 H), 4.34 (q, J ) 7.3
Hz, 2 H), 5.65 (s, 1 H), 6.85 (d, J ) 9.0 Hz, 2 H), 7.28-7.41
(m, 10 H), 7.87 (s, 2 H), 7.90 (d, J ) 9.0 Hz, 2 H). Anal. Calcd
for C27H22N2O4S: C, 68.92; H, 4.71; N, 5.95. Found: C, 69.15;
H, 4.81; N, 5.74.
N-[(2,4-Dich lor op h en yl)t h io]-4-(et h oxyca r b on yl)-2,6-
d ip h en yla n ilin e (9c): colorless fine prisms (MeOH); yield
34%; mp 119-120 °C; IR (KBr) 3360 (NH), 1690 cm-1 (CdO);
1H NMR (CDCl3) δ 1.35 (t, J ) 7.3 Hz, 3 H), 4.34 (q, J ) 7.3
Hz, 2 H), 5.51 (s, 1 H), 6.86 (d, J ) 8.8 Hz, 1 H), 6.98 (dd, J )
8.8 and 2.0 Hz, 1 H), 7.08 (d, J ) 2.0 Hz, 1 H), 7.30-7.36 (m,
10 H), 7.85 (s, 2 H). Calcd for C27H21Cl2NO2S: C, 65.59; H,
4.28; N, 2.83. Found: C, 65.41; H, 4.33; N, 2.81.
N-[(3,5-Dich lor op h en yl)t h io]-4-(et h oxyca r b on yl)-2,6-
d ip h en yla n ilin e (9d ): colorless fine prisms (MeOH); yield
27%; mp 43-45 °C; IR (KBr) 3340 (NH), 1720 cm-1 (CdO);
1H NMR (CDCl3) δ 1.35 (t, J ) 7.3 Hz, 3 H), 4.34 (q, J ) 7.3
Hz, 2 H), 5.61 (s, 1 H), 6.60 (d, J ) 2.0 Hz, 2 H), 6.99 (t, J )
2.0 Hz, 1 H), 7.31-7.42 (m, 10 H), 7.86 (s, 2 H). Anal. Calcd
for C27H21Cl2NO2S: C, 65.59; H, 4.28; N, 2.83. Found: C,
65.27; H, 4.31; N, 2.80.
N-[(3-Nitr op h en yl)th io]-4-(eth oxyca r bon yl)-2,6-bis(4-
ch lor op h en yl)a n ilin e (9e): light yellow fine prisms (EtOH);
yield 26%; mp 64-65 °C; IR (KBr) 3330 (NH), 1710 cm-1
(CdO); 1H NMR (CDCl3) δ 1.35 (t, J ) 7.3 Hz, 3 H), 4.35 (q, J
) 7.3 Hz, 2 H), 5.51 (s, 1 H), 7.05 (d, J ) 8.3 Hz, 1 H), 7.27 (t,
J ) 8.3 Hz, 1 H), 7.29 (s, 8 H), 7.65 (t, J ) 2.0 Hz, 1 H), 7.83
C
26H19Cl2NOS: C, 67.24; H, 4.12; N, 3.02. Found: C, 67.32;
H, 4.16; N, 3.00.
N -[(2,4-D i c h lo r o p h e n y l)t h i o ]-4-a c e t y l-2,6-b i s (4-
ch lor op h en yl)a n ilin e (10g): colorless prisms (EtOH-
benzene); yield 51%; mp 158-159 °C; IR (KBr) 3290 (NH),
1680 cm-1 (CdO); 1H NMR (CDCl3) δ 2.56 (s, 3 H), 5.38 (s,
1H), 6.86 (d, J ) 8.3 Hz, 1 H), 7.03 (dd, J ) 8.3 and 2.0 Hz, 1
H), 7.15 (d, J ) 2.0 Hz, 1 H), 7.25-7.33 (m, 8 H), 7.74 (S, 2
H). Anal. Calcd for C26H17Cl4NOS: C, 58.55; H, 3.22; N, 2.63.
Found: C, 58.64; H, 3.30; N, 2.60.
N-[(2,4-Dich lor op h en yl)t h io]-4-a cet yl-2,6-d i(p h en yl-
d 5)a n ilin e (10i): colorless plates (EtOH-benzene); yield 56%;
mp 136-137 °C; IR (KBr) 3290 (NH), 1680 cm-1 (CdO); 1H
NMR (CDCl3) δ 2.56 (s, 3 H), 5.55 (s, 1 H), 6.86 (d, J ) 8.3 Hz,
1 H), 6.99 (dd, J ) 8.3 and 2.0 Hz, 1 H), 7.08 (d, J ) 2.0 Hz,
1 H), 7.77 (s, 2 H). Anal. Calcd for C26H9Cl2D10NOS: C, 65.82;
H, 4.04; N, 2.95. Found: C, 65.85; H, 4.10: N, 2.93.
N -[(2,4-Dich lor op h e n yl)t h io]-4-cya n o-2,6-d ip h e n yl-
a n ilin e (11c): colorless needles (EtOH-benzene); yield 54%;
mp 128-129 °C; IR (KBr) 3340 (NH), 2230 cm-1 (CN); 1H NMR
(CDCl3) δ 5.55 (s, 1 H), 6.84 (d, J ) 8.3 Hz, 1 H), 7.01 (dd, J
) 8.3 and 2.0 Hz, 1 H), 7.10 (d, J ) 2.0 Hz, 1 H), 7.32-7.38
(m, 10 H), 7.44 (s, 2 H). Anal. Calcd for C25H16Cl2N2S: C,
67.11; H, 3.61; N, 6.26. Found: C, 67.03; H, 3.45: N, 6.22.
N -[(3,5-Dich lor op h e n yl)t h io]-4-cya n o-2,6-d ip h e n yl-
a n ilin e (11d ): light blue prisms (EtOH); yield 90%; mp 131-
133 °C; IR (KBr) 3260 (NH), 2240 cm-1 (CN); 1H NMR (CDCl3)
δ 5.64 (s, 1 H), 6.58 (d, J ) 1.9 Hz, 2 H), 7.18 (t, J ) 1.9 Hz,
1 H), 7.34-7.50 (m, 12 H). Anal. Calcd for C25H16Cl2N2S: C,
67.11; H, 3.61; N, 6.22. Found: C, 66.91; H, 3.48: N, 6.26.
(s, 2 H), 7.93 (d, J ) 8.3 Hz, 1 H). Anal. Calcd for C27H20
-
Cl2N2O4S: C, 60.12; H, 3.74; N, 5.19. Found: C, 59.81; H, 3.77;
N, 5.10.
N-[(4-Nitr op h en yl)th io]-4-(eth oxyca r bon yl)-2,6-bis(4-
ch lor op h en yl)a n ilin e (9f): light yellow needles (EtOH-
benzene); yield 54%; mp 144-145 °C; IR (KBr) 3330 (NH),
N -(2,4-D ic h lo r o p h e n y l)t h io ]-4-n it r o -2,6-d ip h e n y l-
a n ilin e (12): light red needles (EtOH); yield 8%; mp 104-
1
1710 cm-1 (CdO); H NMR (CDCl3) δ 1.36 (t, J ) 7.3 Hz, 3
1
105 °C; IR (KBr) 3320 cm-1 (NH); H NMR (CDCl3) δ 5.69 (s,
H), 4.35 (q, J ) 7.3 Hz, 2 H), 5.49 (s, 1 H), 6.88 (d, J ) 9.0 Hz,
2 H), 7.30 (s, 8 H), 7.84 (s, 2 H), 7.96 (d, J ) 9.0 Hz, 2 H).
Anal. Calcd for C27H20Cl2N2O4S: C, 60.12; H, 3.74; N, 5.19.
Found: C, 59.63; H, 3.71; N, 5.07.
1 H), 6.85 (d, J ) 8.3 Hz, 1 H), 7.02 (dd, J ) 8.3 and 2.0 Hz,
1 H), 7.11 (d, J ) 2.0 Hz, 1 H), 7.34-7.42 (m, 10 H), 8.05 (s,
2 H). Anal. Calcd for C24H16Cl2N2O2S: C, 61.68; H, 3.45; N,
5.99. Found: C, 61.76; H, 3.48; N, 5.96.
N-[(2,4-Dich lor op h en yl)t h io]-4-(et h oxyca r b on yl)-2,6-
bis(4-ch lor op h en yl)a n ilin e (9g): colorless needles (EtOH);
yield 51%; mp 144-145 °C; IR (KBr) 3300 (NH), 1710 cm-1
(CdO); 1H NMR (CDCl3) δ 1.35 (t, J ) 7.3 Hz, 3 H), 4.34 (q, J
) 7.3 Hz, 2 H), 5.35 (s, 1H), 6.86 (d, J ) 8.3 Hz, 1 H), 7.02 (dd,
J ) 8.3 and 2.0 Hz, 1 H), 7.15 (d, J ) 2.0 Hz, 1 H), 7.25-7.32
(m, 8 H), 7.81 (S, 2 H). Anal. Calcd for C27H19Cl4NO2S: C,
57.57; H, 3.40; N, 2.49. Found: C, 57.53; H, 3.42; N, 2.48.
N -(2,4-Dich lor op h e n yl)t h io]-4-ch lor o-2,6-d ip h e n yl-
a n ilin e (13): colorless prisms (hexane); yield 55%; mp 98-
99 °C (dec); IR (KBr) 3340 cm-1 (NH); 1H NMR (CDCl3) δ 5.20
(s, 1 H), 6.84 (d, J ) 8.3 Hz, 1 H), 6.95 (dd, J ) 8.3 and 2.0
Hz, 1 H), 7.06 (d, J ) 2.0 Hz, 1 H), 7.16 (s, 2 H), 7.28-7.33
(m, 10 H). Anal. Calcd for C24H16Cl3NS: C, 63.10; H, 3.54;
N, 3.07. Found: C, 63.15; H, 3.43; N, 3.07.
N-[(3,5-Dich lor op h en yl)t h io]-4-(et h oxyca r b on yl)-2,6-
bis(4-ch lor op h en yl)a n ilin e (9h ): colorless needles (EtOH);
yield 48%; mp 159-161 °C; IR (KBr) 3330 (NH), 1710 cm-1
(CdO); 1H NMR (CDCl3) δ 1.36 (t, J ) 7.3 Hz, 3 H), 4.35 (q, J
) 7.3 Hz, 2 H), 5.45 (s, 1 H), 6.63 (d, J ) 1.5 Hz, 2 H), 7.06 (t,
J ) 1.5 Hz, 1 H), 7.29-7.38 (m, 8 H), 7.83 (S, 2 H). Anal.
Calcd for C27H19Cl4NO2S: C, 57.57; H, 3.40; N, 2.49. Found:
C, 57.56; H, 3.46; N, 2.47.
N-[(2,4-Dich lor op h en yl)t h io]-4-(et h oxyca r b on yl)-2,6-
d i(p h en yl-d 5)a n ilin e (9i): colorless fine plates (MeOH); yield
44%; mp 123-124 °C; IR (KBr) 3370 (NH), 1690 cm-1 (CdO);
1H NMR (CDCl3) δ 1.35 (t, J ) 7.3 Hz, 3 H), 4.34 (q, J ) 7.3
Hz, 2 H), 5.52 (s, 1 H), 6.86 (d, J ) 8.8 Hz, 1 H), 6.98 (dd, J )
8.8 and 2.0 Hz, 1 H), 7.08 (d, J ) 2.0 Hz, 1 H), 7.85 (s, 2 H).
Calcd for C27H11D10Cl2NO2S: C, 64.28; H, 4.20; N, 2.78.
Found: C, 64.20; H, 4.35; N, 2.70.
Isola tion of 4, 5, a n d 6. Precursor 7, 8, or 11 (100 mg)
was dissolved in 20 mL of benzene with stirring. After 1.0 g
of K2CO3 was added, PbO2 (1.0-1.2 g) was added to the
vigrously stirred mixture in some portions during 2 min. After
addition, stirring was continued for further 0.5-1.0 min, and
the strongly colored reaction mixture was filtered. The solvent
was removed by freeze-drying, and the resulting dark blue or
green crystalline powder was crystallized from MeOH (4c, 4d ),
EtOH-ethyl acetate (4a , 4b, 4e, 4f, 4g, 4h , 5b, 5c, 5g), hexane
(6c), or hexanes-ethyl acetate (6d ).
N -[(3-Nit r op h e n yl)t h io]-4-(e t h oxyca r b on yl)-2,6-d i-
p h en ylp h en yla m in yl (4a ): dark blue fine plates; yield 26%;
mp 118-120 °C; IR (KBr) 1705, 1530, 1495, 1345, 1240, 1100,
1055, 1030, 770, 750, 730, 705 cm-1
C
.
Anal. Calcd for
27H21N2O4S: C, 69.06; H, 4.51; N, 5.97. Found: C, 68.77; H,
4.46; N, 5.80.
N-[(4-Nit r op h en yl)t h io]-4-a cet yl-2,6-d ip h en yla n ilin e
(10b): light yellow fine prisms (EtOH-benzene); yield 48%;
mp 150-151 °C; IR (KBr) 3320 (NH), 1670 cm-1 (CdO); 1H
NMR (CDCl3) δ 2.56 (s, 3 H), 5.67 (s, 1 H), 6.85 (d, J ) 8.8 Hz,
2 H), 7.31-7.41 (m, 10 H), 7.79 (s, 2 H), 7.91 (d, J ) 8.8 Hz,
N -[(4-Nit r op h e n yl)t h io]-4-(e t h oxyca r b on yl)-2,6-d i-
p h en ylp h en yla m in yl (4b): dark greenish black plates; yield
23%; mp 112-114 °C; IR (KBr) 1710, 1570, 1515, 1335, 1240,
1105, 850, 770, 740, 705 cm-1. Anal. Calcd for C27H21N2O4S:
C, 69.06; H, 4.51; N, 5.97. Found: C, 68.83; H, 4.80; N, 5.89.

1564 J . Org. Chem., Vol. 63, No. 5, 1998
Miura et al.
N-[(2,4-Dich lor op h en yl)t h io]-4-(et h oxyca r b on yl)-2,6-
d ip h en ylp h en yla m in yl (4c): dark blue fine plates; yield
16%; mp 114-116 °C; IR (KBr) 1710, 1565, 1550, 1495, 1445,
1380, 1330, 1240, 1110, 1060, 1035, 820, 779, 710 cm-1. Anal.
Calcd for C27H20Cl2NO2S: C, 65.72; H, 4.09; N, 2.84. Found:
C, 65.47; H, 4.15; N, 2.77.
on alumina with 1:1 benzene-hexane to give 9.0 mg (0.025
mmol) of 2,4-dichlorophenyl disulfide, 16 mg (0.034 mmol) of
unreacted 12, and 37 mg (0.052 mmol) of 14. 2,4-Dichlorophe-
nyl disulfide was identified by IR and 1H NMR spectra. The
results are shown in Table 3.
N -[(2,4-D i c h lo r o p h e n y l)t h i o ]-N ′-(4-n i t r o -2,6-d i -
p h en ylp h en yl)-2,6-d ip h en yl-1,4-b en zoq u in on e d iim in e
(14): Red prisms (from hexane); mp 228-230 °C; 1H NMR
(CDCl3) δ 6.22-8.28 (m, 27 H); MS m/z (rel intensity) 707 (M+,
N-[(3,5-Dich lor op h en yl)t h io]-4-(et h oxyca r b on yl)-2,6-
d ip h en ylp h en yla m in yl (4d ): dark blue fine prisms; yield
25%; mp 112-114 °C; IR (KBr) 1700, 1555, 1490, 1440, 1410,
1320, 1235, 1105, 1050, 1025, 845, 800, 770, 700, 660 cm-1
.
26), 533 (100), 484 (50), 242 (90). Anal. Calcd for C42H27
-
Cl2N3O2S: C, 71.18; H, 3.84; N, 5.93. Found: C, 71.07; H, 4.01;
N, 5.76.
Anal. Calcd for C27H20Cl2NO2S: C, 65.72; H, 4.09; N, 2.84.
Found: C, 65.47; H, 4.07; N, 2.75.
P r od u ct An a lysis for Decom p osition of 8. Precursor 13
(200 mg, 0.438 mmol) was dissolved in 20 mL of benzene with
stirring. After 2.0 g of K2CO3 was added, 2.0 g of PbO2 was
added in several portions during 2 min, and the resulting
mixture was further stirred for 0.5 min. After filtration, the
filtrate was evaporated, and the residue was chromatographed
on alumina with 1:5 benzene-hexane to give 18 mg (0.050
mmol) of 2,4-dichlorophenyl disulfide, 91 mg (0.199 mmol) of
unreacted 13, and 73 mg (0.104 mmol) of 15. 2,4-Dichlorophe-
nyl disulfide was identified by IR and 1H NMR spectra. The
results are shown in Table 3.
N-[(3-Nitr op h en yl)th io]-4-(eth oxyca r bon yl)-2,6-bis(4-
ch lor op h en yl)p h en yla m in yl (4e): dark blue fine needles;
yield 31%; mp 106-108 °C; IR (KBr) 1705, 1525, 1490, 1345,
1240, 1090, 1045, 1015, 830, 770, 730 cm-1. Anal. Calcd for
C27H19Cl2N2O4S: C, 60.23; H, 3.56; N, 5.20. Found: C, 60.16;
H, 3.61; N, 5.05.
N-[(4-Nitr op h en yl)th io]-4-(eth oxyca r bon yl)-2,6-bis(4-
ch lor op h en yl)p h en yla m in yl (4f): dark greenish blue fine
needles; yield 18%; mp 128-130 °C; IR (KBr) 1700, 1595, 1570,
1520, 1490, 1340, 1240, 1110, 1090, 1045, 1015, 855, 770, 740
cm-1. Anal. Calcd for C27H19Cl2N2O4S: C, 60.23; H, 3.56; N,
5.20. Found: C, 59.99; H, 3.64; N, 5.04.
N -[(2,4-D ic h lo r o p h e n y l)t h io ]-N ′-(4-c h lo r o -2,6-d i-
p h en ylp h en yl)-2,6-d ip h en yl-1,4-b en zoq u in on e d iim in e
(15): red prisms (from ethanol); mp 222-224 °C; 1H NMR
(CDCl3) δ 6.32-7.46 (m, 27 H); MS m/z (rel intensity) 698 (M+,
N-[(2,4-Dich lor op h en yl)t h io]-4-(et h oxyca r b on yl)-2,6-
bis(4-ch lor op h en yl)p h en yla m in yl (4g): dark blue fine
needles; yield 38%; mp 127-128 °C; IR (KBr) 1710, 1490, 1440,
1240, 1110, 1090, 1040, 1015, 820, 770 cm-1. Anal. Calcd for
C27H18Cl4NO2S: C, 57.67; H, 3.23; N, 2.49. Found: C, 57.48;
H, 3.19; N, 2.47.
24), 522 (100), 484 (65), 242 (96). Anal. Calcd for C42H27
-
Cl3N2S: C, 72.26; H, 3.90; N, 4.01. Found: C, 72.24; H, 3.99;
N, 3.97.
X-r a y Cr ysta llogr a p h ic An a lysis of 5c.22,23 A dark green
prismatic crystal of C26H18Cl2NOS (M ) 463.40) having
approximate dimensions of 0.70 × 0.30 × 0.20 mm was
mounted on a glass fiber. All measurements were made on a
Rigaku AFC7R diffractometer with graphite monochromated
Cu KR radiation (λ ) 1.54178 Å). Monoclinic space group P21/
n, a ) 9.0169(9), b ) 25.4085(8), c ) 10.409(1) Å, â ) 108.638-
N-[(3,5-Dich lor op h en yl)t h io]-4-(et h oxyca r b on yl)-2,6-
bis(4-ch lor op h en yl)p h en yla m in yl (4h ): dark violet-blue
fine needles; yield 36%; mp 116-118 °C; IR (KBr) 1700, 1560,
1490, 1400, 1320, 1240, 1105, 1090, 1040, 1015, 830, 800, 770,
660 cm-1. Anal. Calcd for C27H18Cl4NO2S: C, 57.67; H, 3.23;
N, 2.49. Found: C, 57.53; H, 3.51; N, 2.30.
(7)°, V ) 2259.8(3) Å3, Z ) 4, Dc ) 1.362 g cm-3
.
N-[(4-Nitr op h en yl)th io]-4-a cetyl-2,6-d ip h en ylp h en yl-
a m in yl (5b): dark green fine needles; yield 28%; mp 151-
152 °C; IR (KBr) 1675, 1595, 1575, 1510, 1420, 1335, 1230,
The data were collected at a temperature of 23 ( 1 °C using
the ω-2θ scan technique to a maximum 2θ value of 110.1°.
The linear absorption coefficient, µ, for Cu KR radiation is 35.9
cm-1. An empirical absorption correction based on azimuthal
scans of several reflections was applied which resulted in
transmission factors ranging from 0.66 to 1.00.
The structure was solved by heavy-atom Patterson methods
and expanded using Fourier techniques. The non-hydrogen
atoms were refined anisotropically. Hydrogen atoms were
refined isotropically. Of the 3120 reflections collected, 2443
reflections with I > 3.00σ(I) were observed. The final cycle of
full-matrix least-squares refinement was based on the ob-
served reflections and 280 variable parameters and converged
with unweighted and weighted agreement factors of R ) 0.049
and Rw ) 0.044.
1105, 1075, 960, 905, 845, 720, 700 cm-1
. Anal. Calcd for
C26H19N2O3S: C, 71.04; H, 4.37; N, 6.37. Found: C, 70.85; H,
4.40; N, 6.14.
N-[(2,4-Dich lor op h e n yl)t h io]-4-a ce t yl-2,6-d ip h e n yl-
p h en yla m in yl (5c): dark green prisms; yield 52%; mp 102-
103 °C; IR (KBr) 1665, 1570, 1490, 1445, 1420, 1380, 1355,
1320, 1230, 1090, 1035, 965, 900, 810, 780, 700, 565 cm-1. Anal.
Calcd for C26H18Cl2NOS: C, 67.38; H, 3.92; N, 3.02. Found:
C, 67.15; H, 3.96; N, 2.99.
N -[(2,4-D i c h lo r o p h e n y l)t h i o ]-4-a c e t y l-2,6-b i s (4-
ch lor op h en yl)p h en yla m in yl (5g): dark green fine needles;
yield 22%; mp 133-134 °C; IR (KBr) 1675, 1565, 1490, 1445,
1420, 1230, 1090, 1030, 1015, 965, 840, 820, 740, 720 cm-1
.
X-r a y Cr ysta llogr a p h ic An a lysis of 6c.22,23 A dark blue
prismatic crystal of C25H15Cl2N2S (M ) 446.37) having ap-
proximate dimensions of 0.40 × 0.20 × 0.70 mm was mounted
on a glass fiber. All measurements were made on a Rigaku
AFC7R diffractometer with graphite monochromated Cu KR
radiation (λ ) 1.54178 Å). Monoclinic space group P1, a )
10.939(1), b ) 12.186(2), c ) 10.029(1) Å, R ) 106.03(1), â )
113.255(9), γ ) 104.128(10)°, V ) 1082.1(3) Å3, Z ) 2, Dc )
Anal. Calcd for C26H16Cl4NOS: C, 58.66; H, 3.04; N, 2.63.
Found: C, 58.40; H, 3.08; N, 2.47.
N -[(2,4-Dich lor op h e n yl)t h io]-4-cya n o-2,6-d ip h e n yl-
p h en yla m in yl (6c): dark blue prisms; yield 23%; mp 104-
105 °C; IR (KBr) 2220, 1565, 1550, 1490, 1440, 1415, 1380,
1110, 1090, 1035, 890, 870, 820, 805, 780, 755, 715, 700, 610
cm-1
. Anal. Calcd for C25H15Cl2N2S: C, 67.26; H, 3.39; N,
1.370 g cm-3
.
6.28. Found: C, 66.92; H, 3.25, N, 6.24.
The data were collected at a temperature of 23 ( 1 °C using
the ω-2θ scan technique to a maximum 2θ value of 113.2°.
The linear absorption coefficient, µ, for Cu KR radiation is 37.1
cm-1. An empirical absorption correction based on azimuth-
alscans of several reflections was applied which resulted in
transmission factors ranging from 0.55 to 1.00.
N -[(3,5-Dich lor op h e n yl)t h io]-4-cya n o-2,6-d ip h e n yl-
p h en yla m in yl (6d ): dark blue needles; yield 16%; mp 103-
104 °C; IR (KBr) 2220, 1560, 1490, 1440, 1420, 1135, 1100,
890, 795, 780, 735, 705, 660, 610 cm-1
.
Anal. Calcd for
25H15Cl2N2S: C, 67.26; H, 3.39; N, 6.28. Found: C, 67.07;
H, 3.25, N, 6.26.
C
P r od u ct An a lysis for Decom p osition of 7. Precursor 12
(100 mg, 0.214 mmol) was dissolved in 10 mL of benzene with
stirring. After 1.0 g of K2CO3 was added, 1.0 g of PbO2 was
added in several portions during 2 min and the resulting
mixture was further stirred for 0.5 min. After filtration, the
filtrate was evaporated, and the residue was chromatographed
(22) The crystallographic computing was done by the TEXSAN
structure analysis software.
(23) The authors have deposited atomic coordinates for this struc-
ture with the Cambridge Crystallograpic Data Center. The coordinates
can be obtained, on request, from the Director, Cambridge Crystal-
lograhic Data Center, 12 Union Road, Cambridge, CB2 1EZ, UK.

Stable Thioaminyl Radicals Having Functional Groups
J . Org. Chem., Vol. 63, No. 5, 1998 1565
The structure was solved by direct methods and expanded
using Fourier techniques. The non-hydrogen atoms were
refined anisotropically. Hydrogen atoms were refined isotro-
pically. Of the 2568 reflections collected, 2191 reflections with
I > 3.00σ(I) were observed. The final cycle of full-matrix least-
squares refinement was based on the observed reflections and
331 variable parameters and converged with unweighted and
weighted agreement factors of R ) 0.066 and Rw ) 0.068.
valuable suggestions during X-ray crystallographic mea-
surements.
Su p p or tin g In for m a tion Ava ila ble: X-ray crystallo-
graphic data and ORTEP drawings and crystal structures for
5c and 6c (29 pages). This material is contained in libraries
on microfiche, immediately follows this article in microfilm
version of the journal, and can be ordered from ACS; see any
current masthead page for ordering information.
Ack n ow led gm en t. The authors are grateful to
Professor. K. Matsumoto, Osaka City University, for
J O9718206