B. Liu et al. / Tetrahedron xxx (2015) 1e6
5
þ
1
22.2; MS (ESI):m/z calcd for C13
H
10NS [MþH] : 212.05, found
J¼7.5 Hz), 7.89 (d, 1H, J¼7.5 Hz), 7.48 (t, 1H, J¼7.5 Hz), 7.37 (t, 1H,
13
212.10.
J¼7.5 Hz), 7.30 (d, 2H, J¼7.5 Hz), 2.43 (s, 3H); C NMR (125 MHz,
CDCl
3
, TMS)
d
168.2, 154.2, 141.4, 134.9, 131.0, 129.7, 127.5, 126.2,
.2.2. 2-(4-Chlorophenyl)benzothiazole 3b.5b Isolated as a white
125.0, 123.0, 121.6, 21.5; MS (ESI):m/z calcd for C14
226.06, found 226.05.
H12NS [MþH] :
þ
4
ꢀ
1
solid (PE/EtOAc¼5:1, 0.167 g, 85%); mp: 112e113 C; H NMR
(
500 MHz, CDCl , TMS)
3
d
8.02e8.07 (m, 3H), 7.90 (d, 1H, J¼7.5 Hz),
13
4.2.10. 2-(Thiophen-3-yl)benzothiazole 3j.15 Isolated as a white
7
.46e7.52 (m, 3H), 7.40 (t, 1H, J¼7.0 Hz); C NMR (125 MHz, CDCl
3
,
ꢀ
1
TMS)
d
166.6, 154.1, 137.0, 135.1, 132.1, 129.3, 128.7, 126.5, 125.4,
solid (PE/EtOAc¼5:1, 0.153 g, 88%); mp: 113e115 C; H NMR
(500 MHz, CDCl , TMS)
8.05 (d, 1H, J¼8.0 Hz), 8.01e8.02 (m, 1H),
7.87 (d, 1H, J¼8.0 Hz), 7.70 (dd, 1H, J¼5.0, 1.0 Hz), 7.47e7.50 (m, 1H),
þ
123.3, 121.7; MS (ESI):m/z calcd for C13
H
9
ClNS [MþH] : 246.01,
3
d
found 246.05.
1
3
7
CDCl
.43 (dd, 1H, J¼5.0, 3.0 Hz), 7.36e7.39 (m, 1H); C NMR (125 MHz,
4
.2.3. 2-(4-Bromophenyl)benzothiazole 3c.5b Isolated as a white
3
, TMS)
d
162.7, 153.8, 135.9, 134.6, 126.9, 126.6, 126.4, 126.1,
ꢀ
1
þ
solid (PE/EtOAc¼5:1, 0.171 g, 74%); mp: 126e128 C; H NMR
500 MHz, CDCl , TMS)
8.06 (d, 1H, J¼8.5 Hz), 7.93e7.95 (m, 2H),
.88 (d, 1H, J¼8.0 Hz), 7.59e7.62 (m, 2H), 7.48e7.51 (m, 1H),
.37e7.40 (m, 1H); 13C NMR (125 MHz, CDCl
, TMS) 166.7, 154.0,
125.1,123.0,121.6; MS (ESI):m/z calcd for C11
found 218.01.
H
8
NS
2
[MþH] : 218.00,
(
7
7
1
3
d
d
4.2.11. 2-(Furan-2-yl)benzothiazole 3k.5b Isolated as a red solid (PE/
3
ꢀ
1
35.0, 132.5, 132.2, 128.9, 126.5, 125.4, 125.4, 123.3, 121.7; MS
EtOAc¼5:1, 0.130 g, 81%); mp: 102e104 C; H NMR (500 MHz,
CDCl , TMS)
8.08 (d, 1H, J¼8.5 Hz), 7.88 (d, 1H, J¼8.0 Hz), 7.60 (t,
H, J¼1.0 Hz), 7.47e7.50 (m, 1H), 7.38 (t, 1H, J¼7.5 Hz), 7.20 (d, 1H,
þ
(
ESI):m/z calcd for C13
H
9
BrNS [MþH] : 289.96, found 292.00.
3
d
1
.2.4. 2-(4-Fluorophenyl)benzothiazole 3d.5b Isolated as a white
J¼3.5 Hz), 6.58e6.60 (m, 1H); C NMR (125 MHz, CDCl
13
4
3
, TMS)
ꢀ
1
solid (PE/EtOAc¼5:1, 0.134 g, 73%); mp: 102e105 C; H NMR
d
158.2, 154.3, 149.3, 145.3, 134.8, 127.1, 125.8, 123.7, 122.2, 113.1,
þ
(
500 MHz, CDCl
3
, TMS)
d
8.06e8.11 (m, 3H), 7.91 (d, 1H, J¼7.5 Hz),
112.1; MS (ESI):m/z calcd for C11
202.03.
H
8
NOS [MþH] : 202.02, found
13
7
.48e7.51 (m, 1H), 7.38e7.41 (m, 1H), 7.17e7.20 (m, 2H); C NMR
(
1
1
2
125 MHz, CDCl
3
, TMS)
d
166.8, 164.5 (d, J¼250.4 Hz), 154.0, 135.0,
29.9 (d, J¼3.3 Hz), 129.6 (d, J¼8.6 Hz), 126.4, 125.3, 123.2, 121.6,
4.2.12. 5-Chloro-2-phenylbenzothiazole 3l.5b Isolated as a white
þ
ꢀ
1
16.2 (d, J¼22.0 Hz); MS (ESI):m/z calcd for C13
H
9
FNS [MþH] :
solid (PE/EtOAc¼3:1, 0.159 g, 81%); mp: 138e140 C; H NMR
(500 MHz, CDCl , TMS)
8.05e8.08 (m, 3H), 7.80 (d, 1H, J¼8.5 Hz),
30.04, found 230.05.
3
d
13
7
CDCl
.48e7.51 (m, 3H), 7.35 (dd, 1H, J¼8.5, 2.0 Hz); C NMR (125 MHz,
4
.2.5. 2-(4-Cyanophenyl)benzothiazole 3e.5b Isolated as a white
3
, TMS)
d
169.9, 155.0, 133.3, 133.2, 132.3, 131.4, 129.1, 127.6,
ꢀ
1
þ
solid (PE/EtOAc¼3:1, 0.162 g, 86%); mp: 169e171 C; H NMR
500 MHz, CDCl , TMS)
8.20 (d, 2H, J¼6.5 Hz), 8.11 (d, 1H,
J¼6.5 Hz), 7.94 (d, 1H, J¼6.5 Hz), 7.78 (d, 2H, J¼6.5 Hz), 7.45e7.55
m, 2H); 13C NMR (125 MHz, CDCl
, TMS) 165.3, 154.0, 137.5, 135.3,
125.7, 123.1, 122.3; MS (ESI):m/z calcd for C13
H
9
ClNS [MþH] :
(
3
d
246.01, found 246.15.
(
1
3
d
4.3. Procedure for the synthesis of 2-phenylbenzothiazoline
32.8, 127.9, 126.8, 126.1, 123.8, 121.8, 118.3, 114.1; MS (ESI):m/z
þ
calcd for C14
H
9
N
2
S [MþH] : 237.04, found 237.10.
0
2
,2 -Disulfanediyldianiline
(0.4
mmol),
benzaldehyde
(
(
0.8 mmol), Na S$9H O (1.2 mmol), and NaHCO
3 mL) were put into a reaction tube of parallel reactor (Wattecs).
2
2
3
(1.2 mmol) in DMF
4
.2.6. 2-(4-Hydroxyphenyl)benzothiazole 3f.5b Isolated as a gray
ꢀ
1
solid (PE/EtOAc¼1:1, 0.140 g, 77%); mp: 224e226 C; H NMR
ꢀ
When the reaction mixture was stirred at 100 C under N
2
atmo-
(
500 MHz, DMSO, TMS)
d
10.21 (s, 1H), 8.09 (d, 1H, J¼7.5 Hz), 7.98
sphere for 4 h, it was washed with sodium bisulfite solution to
remove the excess aldehyde and extracted with CH Cl . The organic
layers were dried over anhydrous MgSO quickly. After filtered to
remove the MgSO and the solvent was removed under reduced
(
7
dd, 1H, J¼8.0, 0.5 Hz), 7.93e7.95 (m, 2H), 7.49e7.52 (m, 1H),
2
2
13
.39e7.42 (m, 1H), 6.93e6.95 (m, 2H); C NMR (125 MHz, DMSO,
4
TMS)
d
167.9, 161.0, 154.2, 134.6, 129.5, 126.9, 125.4, 124.5, 122.8,
4
þ
122.6, 116.6; MS (ESI):m/z calcd for C13
H10NOS [MþH] : 228.04,
pressure. The crude product was purified by flash chromatography
on silica gel using PE/EtOAc (petroleum ether/ethyl acetate¼12:1)
found 228.05.
16
to provide 12 mg 2-phenylbenzothiazoline. Isolated as a green
4.2.7. 2-(3,4-Dimethoxyphenyl)benzothiazole
3g.14 Isolated
as
1
3
solid; yield: 7%. H NMR (500 MHz, CDCl , TMS) d 7.55 (d, 2H,
ꢀ
a milky white solid (PE/EtOAc¼5:1, 0.173 g, 80%); mp: 130e131 C;
J¼7.5 Hz), 7.32e7.39 (m, 3H), 7.06 (d, 1H, J¼7.5 Hz), 6.96 (t, 1H,
1
H NMR (500 MHz, CDCl
3
, TMS)
d
8.04 (d, 1H, J¼8.5 Hz), 7.87 (d, 1H,
J¼7.5 Hz), 6.77 (t, 1H, J¼7.5 Hz), 6.67 (d, 1H, J¼8.0 Hz), 6.39 (s, 1H);
J¼8.0 Hz), 7.71 (d, 1H, J¼2.0 Hz), 7.60 (dd, 1H, J¼8.5, 2.0 Hz), 7.47 (t,
þ
MS (ESI):m/z calcd for C13
H
12NS [MþH] : 214.06, found 214.10.
1
3
H, J¼7.5 Hz), 7.36 (t, 1H, J¼7.5 Hz), 6.94 (d, 1H, J¼8.5 Hz), 4.02 (s,
H), 3.95 (s, 3H); 13C NMR (125 MHz, CDCl
, TMS) 167.9, 154.2,
d
3
4
.4. Procedure for the reaction of 2-phenylbenzothiazoline
151.6,149.3,134.9,126.7, 126.2,124.9,122.8,121.5,121.2,111.0,109.8,
þ
with disulfide in a NMR tube
5
6.2, 56.1; MS (ESI):m/z calcd for C15
H14NO
2
S [MþH] : 272.07,
found 272.10.
The 2-phenylbenzothiazoline (12 mg) was dissolved with 0.5 mL
deuterated DMF in a NMR tube under the inert atmosphere and
detected by H NMR, then 2,2 -disulfanediyldianiline (9 mg) was
added into the NMR tube and the mixture solution was detected
again by H NMR. Under the inert atmosphere, the mixture solution
was heated to 100 C for an indicated time, and then the reaction
.2.8. 2-(4-Methoxyphenyl)benzothiazole 3h.5b Isolated as a white
4
0
ꢀ
1
solid (PE/EtOAc¼3:1, 0.181 g, 94%); mp: 121e122 C; H NMR
500 MHz, CDCl , TMS)
8.03 (d, 3H, J¼8.5 Hz), 7.86 (d 1H,
J¼8.0 Hz), 7.46 (t, 1H, J¼7.5 Hz), 7.34 (t, 1H, J¼7.5 Hz), 6.99 (d, 2H,
(
3
d
ꢀ
13
J¼9.0 Hz), 3.87 (s, 3H); C NMR (125 MHz, CDCl
3
, TMS) d 167.8,
solution was detected by H NMR at 0.5 h, 1.5 h, 3.5 h, and 5.5 h.
161.9, 154.2, 134.9, 129.1, 126.4, 126.2, 124.8, 122.8, 121.5, 114.4, 55.5;
þ
MS (ESI):m/z calcd for C13
H
12NOS [MþH] : 242.06, found 242.00.
Acknowledgements
4
.2.9. 2-(4-Methylphenyl)benzothiazole 3i.5b Isolated as a white
ꢀ
1
solid (PE/EtOAc¼5:1, 0.175 g, 97%); mp: 84e86 C; H NMR
This work was supported by the National Natural Science
Foundation of China (21362019).
(
500 MHz, CDCl , TMS)
3
d
8.06 (d, 1H, J¼7.5 Hz), 7.99 (d, 2H,