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Russ.Chem.Bull., Int.Ed., Vol. 56, No. 6, June, 2007
Orlova et al.
(4,5,6,7ꢀTetrafluorobenzothiazolꢀ2ꢀyl)sulfenyl dibutylamide
(3b). The yield was 57%, m.p. 102—104 °С (from hexane).
Found (%): С, 48.81; Н, 4.74; F, 20.35; N, 7.36; S, 17.36.
C15Н18F4N2S2. Calculated (%): C, 49.16; Н, 4.95; F, 20.74;
N, 7.65; S, 17.50. 1H NMR (CDCl3), δ: 0.87 (t, 6 H, 2 Me, J =
7.5 Hz); 1.36, 1.78, 3.02 (all m, 12 H, 6 CH2). 19F NMR
(CDCl3), δ: –4.01 (t, 1 F, J1 = J2 = 21.0 Hz); 0.01 (t, 1 F, J1 =
J2 = 21.0 Hz); 7.30 (dd, 1 F, J1 = 21.0 Hz, J2 = 13.0 Hz); 22.50
(dd, 1 F, J1 = 21.0 Hz, J2 = 13.0 Hz).
We showed that di(benzothiazolꢀ2ꢀyl) disulfide, containꢀ
ing no fluorine atoms, does not form sulfenyl amides in
the reaction with amines in ethanol neither at 20 °С nor
under reflux.
The readiness of the reaction of disulfide 2 with amines
can be apparently explained by higher electrophilicity of
the sulfur atom and by higher stability of the leaving fragꢀ
ment of the molecule due to the electron withdrawing
effect of the fluorine atoms.
In conclusion, in the present work a simple method
for the synthesis of di(4,5,6,7ꢀtetrafluorobenzothiazolꢀ
2ꢀyl) disulfide (2) is proposed, which reacts with priꢀ
mary and secondary alkyl amines under mild conditions
to form (4,5,6,7ꢀtetrafluorobenzothiazolꢀ2ꢀyl)sulfenyl
amides 3а—е. This enables one to use disulfide 2 for the
introduction of polyfluoroꢀsubstituted benzothiazole fragꢀ
ment into various aminoꢀcontaining molecules.
(4,5,6,7ꢀTetrafluorobenzothiazolꢀ2ꢀyl)sulfenyl benzylamide
(3c). The yield was 87%, m.p. 177—180 °С (from benzene).
Found (%): С, 48.68; Н, 2.37; F, 22.12; N, 7.91; S, 18.83.
C14Н8F4N2S2. Calculated (%): C, 48.83; Н, 2.34; F, 22.07;
1
N, 8.14; S, 18.62. H NMR (CD3CN), δ: 4.31 (s, 2 H, CH2);
4.58 (br.s, 1 H, NH); 7.32—7.46 (m, 5 H, Ph). 19F NMR
(CD3CN), δ: –5.89 (td, 1 F, J1 = J2 = 19.0 Hz, J3 = 3 Hz);
–0.67 (td, 1 F, J1 = J2 = 19.0 Hz, J3 = 1 Hz); 9.70 (ddd, 1 F, J1 =
22.0 Hz, J2 = 13.0 Hz, J3 = 3 Hz); 22.95 (ddd, 1 F, J1 = 22.0 Hz,
J2 = 13.0 Hz, J3 = 1 Hz).
(4,5,6,7ꢀTetrafluorobenzothiazolꢀ2ꢀyl)sulfenyl piperidide
(3d). The yield was 66%, m.p. 121—123 °С (from ethanol).
Found (%): С, 44.82; Н, 3.40; F, 23.28; N, 8.53; S, 19.55.
C12Н10F4N2S2. Calculated (%): C, 44.71; Н, 3.13; F, 23.57;
Experimental
NMR spectra were recorded on a Bruker АСꢀ200 spectroꢀ
meter (200 (1H) and 188.2 MHz (19F)). The H chemical shifts
1
1
N, 8.69; S, 19.89. H NMR (CDCl3), δ: 1.45—1.82 (m, 6 H,
3 CH2 of piperidine); 3.20 (m, 4 H, 2 CH2 of piperidine).
19F NMR (CDC13), δ: –0.06 (t, 1 F, J1 = J2 = 20.5 Hz); 2.88 (t,
1 F, J1 = J2 = 19.5 Hz); 11.97 (dd, 1 F, J1 = 19.5 Hz, J2 =
14.5 Hz); 22.89 (dd, 1 F, J1 = 20.5 Hz, J2 = 14.5 Hz).
(4,5,6,7ꢀTetrafluorobenzothiazolꢀ2ꢀyl)sulfenyl morpholide
(3e). The yield was 88%, m.p. 160—162 °С (from benꢀ
zene—hexane, 1 : 2). Found (%): С, 41.23; H, 2.42; F, 23.15;
N, 8.70; S, 19.73. C11H8F4N2S2O. Calculated (%): C, 40.73;
H, 2.49; F, 23.43; N, 8.64; S, 19.77. 1H NMR (CDCl3), δ: 3.26,
3.84 (both m, 4 H each, H of morpholine). 19F NMR (CDC13),
are given in δ scale, the signal of the residual protons in CDCl3
(δ 7.24) and CD3CN (δ 1.96) serving as the internal standard.
The 19F chemical shifts are given in ppm relatively to С6F6. The
highꢀresolution mass spectrum was recorded on a Finnigan
MAT 8200 spectrometer (direct injection, temperature of injecꢀ
tor, 314 °С, energy of the ionizing electrons, 70 eV).
Di(4,5,6,7ꢀtetrafluorobenzothiazolꢀ2ꢀyl) disulfide (2). Hydroꢀ
gen peroxide (40% aq., 35 mL) was added dropwise to a suspenꢀ
sion of 2ꢀmercaptoꢀ4,5,6,7ꢀtetrafluorobenzothiazole (1) (5.0 g)
in ethanol (50 mL) with stirring. The reaction mixture was stirred
for 30 min at ~20 °C, the precipitate was filtered off, washed
with water, and dried in air. Disulfide 2 (4.28 g, 85%) was
obtained, m.p. 113—116 °С (from hexane). Found (%): С, 35.79;
F, 31.92; N, 5.76; S, 26.90. C14F8N2S4. Calculated (%): C, 35.30;
F, 31.90; N, 5.88; S, 26.92. 19F NMR (CDCl3), δ: 3.89 (t, 1 F,
J1 = J2 = 20.5 Hz); 5.06 (t, 1 F, J1 = J2 = 19.5 Hz); 14.42 (dd,
1 F, J1 = 19.5 Hz, J2 = 14.5 Hz); 24.90 (dd, 1 F, J1 = 20.5 Hz,
J2 = 14.5 Hz).
δ: 0.77 (t, 1 F, J1 = J2 = 20.5 Hz); 3.51 (t, 1 F, J1 = J2
=
19.5 Hz); 12.50 (dd, 1 F, J1 = 19.5, J2 = 14.0 Hz); 23.22 (dd, 1 F,
J1 = 20.5 Hz, J2 = 14.0 Hz). HRMS, found: m/z 324.0012 [M]+.
Calculated: M = 324.0014.
This work was financially supported by the Siberian
Branch of the Russian Academy of Sciences (Integrational
Grants 15, 17, 33, and 65).
Reaction of disulfide 2 with amines (general procedure). An
amine (40 mmol) was added to a suspension of disulfide 2 (0.48 g,
10 mmol) in EtOH (10 mL), and this was stirred for 30 min at
~20 °C with magnetic stirrer. The reaction mixture was poured
to the iceꢀcold water, the formed precipitate was filtered off,
washed with water, and dried in air to obtain sulfenyl amides 3.
The filtrate was acidified with 3% aq. HCl, the precipitate was
filtered off, washed with water, and dried in air to obtain
mercaptobenzothiazole 1 (0.15—0.20 g).
References
1. Vspomogatel'nye veshchestva dlya polimernykh materialov [Auxꢀ
iliary Substances for Polymeric Materials], Eds К. B. Piotrovsky
and К. Yu. Salnis, Khimiya, Moscow, 1966, 176 pp. (in
Russian).
2. F. E. Herkes, J. Fluorine Chem., 1979, 13, 1.
3. L. Zhu and M. Zhang, J. Org. Chem., 2004, 69, 7371.
4. US Pat. 2758995; Chem. Abstrs, 1957, 51, 5840.
5. H. Moustafa, N. Y. Abdou, and M. M. Hamed, Egipt. J. Chem.,
2000, 43, 309; Chem. Abstrs, 2001, 134, 131201.
6. US Pat. 2417989; Chem. Abstrs, 1947, 41, 4517.
7. S. Torii, H. Tanaka, and M. Ukida, J. Org. Chem., 1978,
43, 3223.
(4,5,6,7ꢀTetrafluorobenzothiazolꢀ2ꢀyl)sulfenyl butylamide
(3а). The yield was 63%, m.p. 54—56 °С (from hexane).
Found (%): С, 42.97; Н, 3.27; F, 24.56; N, 8.81; S, 20.42.
C11Н10F4N2S2. Calculated (%): C, 42.57; Н, 3.25; F, 24.49;
1
N, 9.03; S, 20.67. H NMR (CDCl3), δ: 0.93 (t, 3 H, Me, J =
8.0 Hz); 1.41, 1.59, 3.17 (all m, 6 H, 3 CH2); 3.36 (br.t, 1 H,
NH, J = 6.0 Hz). 19F NMR (CDCl3), δ: 0.17 (t, 1 F, J1 = J2 =
20.5 Hz); 3.10 (t, 1 F, J1 = J2 = 19.5 Hz); 12.18 (dd, 1 F, J1 =
19.5 Hz, J2 = 15.0 Hz); 23.12 (dd, 1 F, J1 = 20.5 Hz, J2
15.0 Hz).
=
Received February 26, 2007;
in revised form April 13, 2007