Helv. Chim. Acta 2016, 99, 130 – 132
131
Scheme
(16), 122 (21), 106 (100), 90 (9). Anal. calc. for C14H10N4O2Se (345.21):
C 48.71, H 2.92, N 16.23; found: C 49.16, H 2.89, N 16.32.
A plausible mechanism for the formation of com-
pounds 3 is given in the Scheme. The acyl isoselenocyanate
4, formed from 1 and KSeCN, undergoes nucleophilic
attack by 2 to afford intermediate 5. This intermediate is
converted to product 3 via cyclization and elimination of
H2O.
In conclusion, acyl isoselenocyanate intermediates,
generated from acyl chlorides and KSeCN, are trapped
by benzene-1,2-diamine to afford 1,3,5-triazepineselone
derivatives. The potential diversity of this type of reaction
and available starting materials are the main advantages of
this methodology.
4-(2-Chlorophenyl)-1,3-dihydro-2H-1,3,5-benzotriazepine-2-selone
(3d). Yield: 0.26 g (78%). Pale-green powder. M.p. 1918 (dec.). IR
(KBr): 3436, 1634, 1520. 1H-NMR: 7.36 – 7.49 (m, 3 arom. H); 7.51 – 7.56
(m, 3 arom. H); 7.88 – 7.97 (m, 2 arom. H); 11.89 (s, NH); 12.63 (s, NH).
13C-NMR: 123.8 (CH); 128.1 (CH); 130.5 (CH); 130.9 (CH); 131.2
(CH); 131.3 (C); 131.5 (CH); 131.7 (CH); 132.3 (C); 132.4 (C); 133.1
(C); 133.5 (CH); 167.5 (C¼N); 182.6 (C¼Se). EI-MS: 334 (3, Mþ), 258
(12), 244 (15), 228 (8), 223 (9), 111 (20), 106 (39), 90 (53), 76 (100).
Anal. calc. for C14H10ClN3Se (334.66): C 50.24, H 3.01, N 12.56; found:
C 50.69, H 3.07, N 12.69.
1,3-Dihydro-4-(4-methylphenyl)-2H-1,3,5-benzotriazepine-2-selone
(3e). Yield: 0.21 g (67%). Pale-green powder. M.p. 1888 (dec.). IR
(KBr): 3429, 1632, 1505. 1H-NMR: 2.49 (s, Me); 7.10 – 7.13 (m, 2 arom.
3
H); 7.33 (d, J ¼ 7.2, 2 arom. H); 7.43 – 7.46 (m, 2 arom. H); 8.01 – 8.04
(m, 2 arom. H); 10.21 (s, NH); 12.13 (s, NH). 13C-NMR: 21.6 (Me);
127.3 (C); 127.6 (CH); 128.2 (CH); 128.5 (C); 129.1 (2 CH); 129.4 (2
CH); 134.8 (C); 135.2 (CH); 143.9 (C); 144.3 (CH); 168.5 (C¼N); 182.3
(C¼Se). EI-MS: 314 (8, Mþ), 238 (100), 223 (11), 208 (7), 196 (9), 118
(43), 106 (24), 91 (35), 76 (52). Anal. calc. for C15H13N3Se (314.24): C
57.33, H 4.17, N 13.37; found: C 57.68, H 4.22, N 13.48.
Experimental Part
General. All chemicals were obtained commercially and used
without further purification. IR Spectra: Shimadzu-IR-460 spectrom-
.
eter; in cmÀ1 1H- and 13C-NMR spectra: Bruker DRX-500 Avance
instrument at 500.1 and 125.7 MHz, resp.; d in ppm, J in Hz. EI-MS:
Finnigan-MAT-8430EI-MS mass spectrometer; at 70 eV; in m/z (rel.
%). Elemental analyses: Vario EL III CHNOS elemental analyzer.
General Procedure for the Preparation of Compounds 3. To a
stirred soln. of KSeCN (0.144 g, 1 mmol) in acetone (2 ml), a soln. of
acyl chloride 1 (1 mmol) in acetone (2 ml) was added at r.t. After
10 min, a soln. of benzene-1,2-diamine (2; 0.108 g, 1 mmol) in acetone
(2 ml) was added. After completion of the reaction (ca. 5 h; TLC
(AcOEt/hexane 1:3) monitoring), the precipitate was filtered and
washed with Et2O to give the product.
1,3-Dihydro-4-phenyl-2H-1,3,5-benzotriazepine-2-selone (3a).
Yield: 0.22 g (74%). Cream powder. M.p. 1938 (dec.). IR (KBr):
3426, 1654, 1525. 1H-NMR: 6.97 – 6.98 (m, 1 arom. H); 7.21 (t, 3J ¼ 7.2, 1
arom. H); 7.47 – 7.52 (m, 3 arom. H); 7.64 (t, 3J ¼ 7.3, 1 arom. H); 7.84 –
7.88 (m, 3 arom. H); 9.55 (s, NH); 12.77 (s, NH). 13C-NMR: 121.7 (C);
125.9 (C); 127.4 (CH); 127.8 (2 CH); 128.9 (CH); 129.3 (2 CH); 131.2
(CH); 134.0 (CH); 134.5 (CH); 140.3 (C); 166.8 (C¼N); 182.2 (C¼Se).
EI-MS: 300 (4, Mþ), 223 (9), 210 (27), 194 (100), 179 (21), 121 (7), 106
(68), 90 (18), 77 (56). Anal. calc. for C14H11N3Se (300.22): C 56.01, H
3.69, N 14.00; found: C 56.46, H 3.74, N 14.08.
4-(4-Chlorophenyl)-1,3-dihydro-2H-1,3,5-benzotriazepine-2-selone
(3b). Yield: 0.27 g (80%). Green powder. M.p. 1968 (dec.). IR (KBr):
3422, 1668, 1519. 1H-NMR: 7.49 – 7.53 (m, 4 arom. H); 7.80 – 7.87 (m, 4
arom. H); 9.47 (s, NH); 12.67 (s, NH). 13C-NMR:125.9 (C); 127.5
(CH); 128.1 (C); 129.2 (2 CH); 129.7 (2 CH); 130.4 (C); 131.6 (CH);
134.5 (CH); 136.9 (C); 140.9 (CH); 165.6 (C¼N); 182.1 (C¼Se). EI-
MS: 334 (3, Mþ), 258 (20), 244 (78), 223 (18), 196 (8), 138 (100), 111
(43), 90 (16), 76 (23). Anal. calc. for C14H10ClN3Se (334.66): C 50.24, H
3.01, N 12.56; found: C 50.56, H 3.05, N 12.67.
1,3-Dihydro-4-(4-nitrophenyl)-2H-1,3,5-benzotriazepine-2-selone
(3c). Yield: 0.29 g (84%). Pale-brown powder. M.p. 1948 (dec.). IR
(KBr): 3433, 1625, 1534, 1337. 1H-NMR: 7.16 – 7.54 (m, 3 arom. H);
7.96 – 8.32 (m, 5 arom. H); 10.66 (s, NH); 12.62 (s, NH). 13C-NMR:
122.5 (CH); 123.4 (2 CH); 123.6 (CH); 125.9 (C); 129.2 (CH); 129.7 (2
CH); 129.9 (C); 135.3 (C); 140.2 (C); 149.0 (CH); 167.9 (C¼N); 182.4
(C¼Se). EI-MS: 345 (2, Mþ), 255 (20), 239 (81), 223 (11), 196 (95), 149
4-Benzyl-1,3-dihydro-2H-1,3,5-benzotriazepine-2-selone (3f).
Yield: 0.23 g (73%). Brown powder. M.p. 1868 (dec.). IR (KBr):
1
3412, 1673, 1519. H-NMR: 3.74 (s, CH2); 7.23 – 7.29 (m, 4 arom. H);
7.31 – 7.34 (m, 4 arom. H); 7.71 – 7.73 (m, 1 arom. H); 11.98 (s, NH);
12.47 (s, NH). 13C-NMR: 42.2 (CH2); 125.3 (C); 126.5 (CH); 127.0
(CH); 127.6 (C); 128.2 (CH); 128.4 (2 CH); 129.1 (CH); 129.4 (2 CH);
134.1 (C); 135.6 (CH); 169.6 (C¼N); 181.5 (C¼Se). EI-MS: 314 (9,
Mþ), 237 (43), 223 (17), 208 (10), 196 (21), 118 (38), 106 (29), 91 (100),
77 (34). Anal. calc. for C15H13N3Se (314.24): C 57.33, H 4.17, N 13.37;
found: C 57.62, H 4.22, N 13.49.
1,3-Dihydro-4-(2-methylphenyl)-2H-1,3,5-benzotriazepine-2-selone
(3g). Yield: 0.19 g (60%). Pale-yellow powder. M.p. 1898 (dec.). IR
(KBr): 3425, 1625, 1545. 1H-NMR: 2.31 (s, Me); 7.20 – 7.40 (m, 6 arom.
H); 7.90 – 7.95 (m, 2 arom. H); 12.10 (s, NH); 12.82 (s, NH). 13C-NMR:
20.2 (Me); 125.9 (C); 126.3 (CH); 127.8 (C); 128.5 (CH); 128.9 (CH);
129.7 (C); 131.4 (CH); 131.9 (CH); 132.7 (C); 134.6 (CH); 135.3 (CH);
136.9 (CH); 171.3 (C¼N); 182.4 (C¼Se). EI-MS: 314 (9, Mþ), 238
(100), 223 (13), 208 (10), 196 (6), 118 (26), 106 (7), 91 (20), 76 (48).
Anal. calc. for C15H13N3Se (314.24): C 57.33, H 4.17, N 13.37; found: C
57.67, H 4.22, N 13.46.
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