Stable Thioaminyl Radicals
J . Org. Chem., Vol. 65, No. 23, 2000 7895
Ta ble 4. UV-Vis Sp ectr a of 1-3 in Ben zen e
9 H), 7.45 (s, 2H), 7.58 (d, J ) 8.3 Hz, 4 H), 7.60 (d, J ) 8.3
Hz, 2H), 8.24 (d, J ) 4.9 Hz, 2 H). Anal. Calcd for C28H21N3S:
C, 77.93; H, 4.90; N, 9.74. Found: C, 78.30; H, 4.81; N, 9.77.
N -(2-P y r i m i d y lt h i o )-2,4,6-t r i s (4-c h lo r o p h e n y l)-
a n ilin e (6b): colorless prisms, mp 143.5-145 °C; IR (KBr)
radical
λ )
max, nm (ꢀ, L mol-1 cm-1
1a
342 (11800), 383 (16900), 394 (16800),
533 (1880, sh), 643 (8540)
355 (18700, sh), 396 (27200),
533 (2870, sh), 656 (12300)
332 (9780), 381 (20100), 396 (20800),
430 (8670, sh), 556 (3330, sh), 656 (8750)
325 (9190), 388 (18900),
558 (3990, sh), 653 (8060)
535 (sh), 620
1
3340 cm-1 (NH); H NMR (CDCl3) δ 5.68 (s, 1H), 6.86 (t, J )
1b
1c
1d
4.9 Hz, 1 H), 7.36 (s, 2H), 7.37 (d, J ) 8.3 Hz, 2H), 7.40 (d, J
) 8.3 Hz, 4 H), 7.49 (d, J ) 8.3 Hz, 4H), 7.50 (d, J ) 8.3 Hz,
2 H), 8.29 (d, J ) 4.9 Hz, 2 H). Anal. Calcd for C28H18Cl3 N3S:
C, 62.87; H, 3.39; N, 7.86. Found: C, 63.11; H, 3.66; N, 7.62.
N-(2-P yr im id ylt h io)-2,4,6-t r is(p h en yl-d 5)a n ilin e (6a -
d ): colorless prisms, mp 70-72 °C; IR (KBr) 3340 cm-1 (NH);
1H NMR (CDCl3) δ 5.84 (s, 1H), 6.77 (t, J ) 4.9 Hz, 1 H), 7.45
(s, 2H), 8.24 (d, J ) 4.9 Hz, 2 H).
Gen er a l P r oced u r e for Isola tion of 1. To a vigorously
stirred solution of 300 mg of 4 in 20 mL of benzene was added
9.0 g of PbO2 over 2 min in several portions, and stirring was
continued for an additional 1 min. After filtration, the benzene
was removed by freeze-drying, and the residue was crystallized
from ethanol-ethyl acetate (1a ,b,d ) or ethanol (1c).
N-[(2-Ben zoth ia zolyl)th io]-2,4,6-tr ip h en ylp h en yla m i-
n yl (1a ): dark green needles; mp 151-153 °C; yield 22%. Anal.
Calcd for C31H21N2S2: C, 76.67; H, 4.36; N, 5.77. Found: C,
76.39; H, 4.58; N, 5.58.
N-[(2-Ben zoth ia zolyl)th io]-2,4,6-tr is(4-ch lor op h en yl)-
p h en yla m in yl (1b): dark green plates; mp 154-156 °C; yield
18%. Anal. Calcd for C31H18Cl3N2S2: C, 63.22; H, 3.08; N, 4.76.
Found: C, 63.49; H, 3.22; N, 4.53.
N-[(2-Ben zoth ia zolyl)th io]-4-a cetyl-2,6-d ip h en ylp h en -
yla m in yl (1c): dark blue plates; mp 133-135 °C; yield 15%.
Anal. Calcd for C27H19N2OS2: C, 71.81; H, 4.24; N, 6.20.
Found: C, 71.58; H, 4.30; N, 5.90.
2a
3a a
3ba
536, 612
543, 619
a
Because the radicals are not isolated, only λmax values are
shown.
captans with I2 in ethanol. 2-Benzothiazolesulfenyl, 2-benz-
oxazolesulfenyl, and 2-pyrimidesulfenyl chlorides were pre-
pared by bubbling Cl2 into a solution of the corresponding bis-
(2-benzothiazolyl) or bis(2-pyrimidyl) disulfide (3.0-3.8 mmol)
or 2-mercaptobenzoxazole (4.8 mmol) in CH2Cl2 (20 mL) at
room temperature for ca. 0.5-2 min until the solution turned
reddish yellow.20 Then, N2 was bubbled to remove the excess
of Cl2 in the sulfenyl chloride solution.
Gen er a l P r oced u r e for P r ep a r a tion of 4. To a stirred
solution of 4.00 mmol of an aniline and 3.8 mL of Et3N in 200
mL of dry ether was added a solution of 2-benzothiazolesulfe-
nyl chloride, prepared from 1.00 g (3.0 mmol) of bis(2-
benzothiazolyl) disulfide, and the resulting mixture was stirred
for 2 h at 0 °C. After filtration, the filtrate was evaporated
under reduced pressure, and the residue was column chro-
matographed on alumina at 0 °C with 1:3 hexane-benzene
(4a ,d ), 2:3 hexane-benzene (4b), or 1:5 ethyl acetate-hexane,
giving 4a in 42% yield, 4b in 30% yield, 4c in 68% yield, and
4d in 56% yield. The products contained considerable amounts
of 1. The crude products were used in the following reaction
without further purification. The deuterated compound 4a -d
was prepared from 2,4,6-tris(phenyl-d5)aniline and 2-ben-
zothiazolesulfenyl chloride in the same manner as for 4a .
Gen er a l P r oced u r e for P r ep a r a tion of 5. To a stirred
solution of 3.12 mmol of 2,4,6-triphenylaniline and 3.0 mL of
Et3N in 150 mL of dry ether was added a solution of
2-benzoxazolesulfenyl chloride, prepared from 0.72 g (4.8
mmol) of 2-mercaptobenzoxazole, and the resulting mixture
was stirred for 2 h at 0 °C. After filtration, filtrate was
evaporated under reduced pressure, and the residue was
column chromatographed on alumina at 0 °C with 1:1 hexane-
benzene. After evaporation under reduced pressure, the resi-
due obtained was used in the next reaction without purifica-
tion. The deuterated compound 5-d was prepared from 2,4,6-
tris(phenyl-d5)aniline and 2-benzoxazolesulfenyl chloride in the
same manner as for 5.
Gen er a l P r oced u r e for P r ep a r a tion of 6. To a stirred
solution of 5.0 mmol of aniline and 3.5 mL of Et3N in 200 mL
of dry ether was added a solution of 2-pyrimidinesulfenyl
chloride, prepared from 0.83 g (3.75 mmol) of bis(2-pyrimidyl)
disulfide, and the resulting mixture was stirred for 2 h at 0
°C. After filtration, filtrate was evaporated under reduced
pressure, and the residue was column chromatographed on
alumina at 0 °C with 1:5 ethyl acetate-hexane (6a ) or 2:3
hexane-benzene (6b), giving 6a in 43% yield and 6b in 65%
yield. Recrystallization from hexanes-ethyl acetate gave color-
less prisms. The deuterated compound 6a -d was prepared from
2,4,6-tris(phenyl-d5)aniline and 2-pyrimidinesulfenyl chloride
in the same manner as for 6a .
N-[(2-Ben zoth ia zolyl)th io]-4-(eth oxyca r bon yl)-2,6-bis-
(4-ch lor op h en yl)p h en yl a m in yl (1d ): dark blue needles; mp
163-165 °C; yield 11%. Anal. Calcd for C28H19Cl2N2O2S2: C,
61.09; H, 3.48; N, 5.09. Found: C, 60.96; H, 3.57; N, 4.92.
UV-Vis Spectral Data. The The UV-Vis spectral data for
1-3 are summarized in Table 4.
X-r a y Cr ysta llogr a p h ic An a lysis for 1c.21 A black plate-
let crystal of C27H19N2OS2 (451.58) having approximate dimen-
sions of 0.5 × 0.5 × 0.1 mm was mounted on a glass fiber. All
measurements were made on a Rigaku RAXIS-RAPID Imaging
Plate diffractometer with graphite monochromated Mo KR
radiation (λ ) 0.71069 Å): monoclinic space group P21/c, a )
12.3168(4), b ) 11.4207(5), c ) 16.1587(6) Å, â ) 103.645(2)°,
V ) 2208.8(1) Å3, Z ) 4, and Dc ) 1.358 g cm-3. The data were
collected at 23 ( 1 °C to a maximum 2θ value of 55.0°. A total
of 44 images, corresponding to 220.0° oscillation angles, were
collected with 2 different goniometer settings. Exposure time
was 7.50 min/deg. The camera radius was 127.40 mm. Readout
was performed in the 0.150 mm pixel mode. Data were
processed by the PROCESS-AUTO program package. Of 20997
reflections measured 5055 were unique (Rini ) 0.045), 2615 of
which were considered as observed (I > 3.10σ(I)).
The structure was solved by direct methods and expanded
using Fourier techniques.22 The non-hydrogen atoms were
refined anisotropically. Hydrogen atoms were placed in the
fixed position and not refined. The final cycle of full matrix
least-squares refinement was based on 2615 observed reflec-
tions and 290 variable parameters and converged with un-
weighted and weighted agreement factors of R ) 0.071 and
Rw ) 0.120. GOF ) 1.91.
Ack n ow led gm en t. This work was in part finan-
cially supported by Grant-in-Aids for Scientific Research
on Priority Area (A) (No.10146246 and 11133253) from
the Ministry of Education, Science, Sports and Culture
of J apan.
N-(2-P yr im id ylth io)-2,4,6-tr ip h en yla n ilin e (6a ): color-
less prisms, mp 71-73 °C; IR (KBr) 3340 cm-1 (NH); 1H NMR
(CDCl3) δ 5.84 (s, 1H), 6.77 (t, J ) 4.9 Hz, 1 H), 7.27-7.44 (m,
Su p p or tin g In for m a tion Ava ila ble: Tables of X-ray
structural data for compound 1c and ESR spectra of 1a ,b,d ,
2, 2-d, 3a ,b, and 3a -d. This material is available free of charge
(20) Long time bubbling of Cl2 yielded unsoluble materials.
(21) The crystallograhpic computing was done by the TEXSAN
structure analysis software.
(22) SIR92: Altomare, A.; Burla, M. C.; Camalli, M.; Cascarano, M.;
Giacovazzo, C.; Guagliardi, A.; Polidori, G. J . Appl. Crystallogr. 1994,
27, 435.
J O000901Q