New Method for the Preparation of Dibenzo[b,f ][1,4]thiazepines 249
not be isolated by recrystallization [6,7a,7c]; Yield
10-Amino-9-hydroxy-9-isopropyl-9H-
thioxanthenium mesitylenesulfonate (3d)
1
1
84% (determined by H NMR); H NMR (400 MHz,
CDCl3) δ 1.53 (s, 3H), 7.22–7.41 (m, 6H), 7.88 (dd, J1
= 6.2 Hz, J2 = 1.6 Hz, 2H); IR (coat) 3424 cm−1(OH),
2965 cm−1 (CH); MS (m/z) 228 (M+).
1
Yield 78%; mp 179◦C; H NMR (400 MHz, CD3OD)
δ 0.78 (d, J = 6.4 Hz, 6H), 1.74 (sept, J = 6.4 Hz,
1H), 2.23 (s, 3H), 2.62 (s, 6H), 6.86 (s, 2H), 7.73 (t, J
= 8.0 Hz, 2H), 7.80 (t, J = 8.0 Hz, 2H), 8.05 (d, J =
8.0 Hz, 2H), 8.08 (d, J = 8.0 Hz, 2H); 13C NMR (100
MHz, CD3OD) δ 17.3, 20.8, 23.3, 40.9, 77.2, 125.9,
128.8, 128.9, 130.1, 131.7, 133.2, 138.3, 140.2, 140.9,
142.6; IR (KBr) 3030–3500 cm−1 (OH, NH2); 2971,
2934, 2875 cm−1(CH); Anal. Calcd for C25H29NO4S2:
C, 63.67; H, 6.20; N, 2.79; Found: C, 63.38; H, 6.26;
N, 3.04.
9-Ethyl-9H-thioxanthen-9-ol (2c)
1
Yield 88%; mp 72◦C; H NMR (400 MHz, CDCl3) δ
0.69 (t, J = 7.4 Hz, 3H), 1.83 (q, J = 7.4, Hz, 2H),
7.23 (dt, J1 = 7.4 Hz, J2 = 1.2 Hz, 2H), 7.29–7.33 (m,
2H), 7.38–7.40 (m, 2H), 7.80–7.83 (m, 2H); 13C NMR
(100 MHz, CDCl3) δ 8.0, 31.3, 75.6, 125.5, 126.26,
126.33, 127.1, 130.1, 140.2; IR (KBr) 3430 cm−1(OH),
2969, 2932, 2887 cm−1 (CH); MS (m/z) 242 (M+);
Anal. Calcd for C15H14OS: C, 74.34, H, 5.82; Found:
C, 74.51, H, 5.87.
Dibenzo[b,f][1,4]thiazepine (6a)
1
Yield 43%; mp 115◦C; H NMR (400 MHz, CDCl3) δ
7.15–7.19 (m, 1H), 7.29–7.46 (m, 7H), 8.9 (s, 1H); 13
C
NMR (100 MHz, CDCl3)δ 126.9, 127.2, 128.2, 128.8,
129.2, 129.4, 131.4, 131.6, 132.7, 137.2, 139.3, 148.5,
162.2; IR (KBr) 1628 cm−1 (C N); MS (m/z) 211 (M+);
Anal. Calcd for C13H9NS: C, 73.90, H, 4.29, N, 6.63;
Found: C, 73.52, H, 4.29, N, 6.28.
9-Isopropyl-9H-thioxanthen-9-ol (2d)
The crude product contained as impurity of
thioxanthene-9-one [7a]. Thioxanthene-9-one (1)
was removed partly by recrystallizing from acetone
to obtain 2d in 95% purity. Yield 80% (determined
1
1
by H NMR); H NMR (400 MHz, CDCl3)δ 0.70 (d,
J = 6.8 Hz, 6H), 2.40 (sept, J = 6.8 Hz, 1H), 7.23
(dt, J1 = 7.6 Hz, J2 = 1.6 Hz, 2H), 7.30 (dt, J1 = 7.6
Hz, J2 = 1.6 Hz, 2H), 7.41 (dd, J1 = 7.6 Hz, J2 = 1.6
Hz, 2H), 7.78 (dd, J1 = 7.6 Hz, J2 = 1.6 Hz, 2H); IR
(coat) 3436 cm−1(OH), 2965, 2933, 2872 cm−1 (CH);
MS (m/z) 256 (M+).
11-Methyl-dibenzo[b,f][1,4]thiazepine (6b)
Yield 21%; oil; 1H NMR (400 MHz, CDCl3) δ 2.66 (s,
3H), 7.05 (dt, J1 = 7.6 Hz, J2 = 1.6 Hz, 1H), 7.18
(dd, J1 = 7.6 Hz, J2 = 1.6 Hz, 1H), 7.24–7.34 (m, 3H),
7.39–7.47 (m, 3H); 13C NMR (100 MHz, CDCl3) δ 29.5,
125.2, 125.4, 127.8, 128.3, 128.7, 129.0, 130.6, 131.8,
132.3, 139.3, 139.8, 148.6, 169.7; IR (coat) 2921 cm−1
(CH), 1628 cm−1 (C N); HRMS Calcd for C14H11NS:
225.0612; Found 225.0580.
9-Phenyl-9H-thioxanthen-9-ol (2e)
Yield 65%; mp 108◦C; H NMR (400 MHz, CDCl3) δ
1
11-Eethyl-dibenzo[b,f][1,4]thiazepine (6c)
6.97–7.00 (m, 2H), 7.15–7.19 (m, 3H), 7.26–7.31 (m,
2H), 7.36–7.44 (m, 4H), 8.03 (dd, J1 = 8.0 Hz, J2 = 0.8
Hz, 2H); 13C NMR (100 MHz, CD3CN) δ 77.3, 127.3,
127.5, 127.6, 127.9, 128.3, 128.4, 128.8, 132.0, 141.5,
144.9; IR (KBr) 3303 cm−1(OH); MS (m/z) 290 (M+)
[5–7].
Yield 58%; mp 67–68◦C; 1H NMR (400 MHz, CDCl3)
δ 1.27 (t, J = 7.6 Hz, 3H), 2.94 (dq, J1 = 7.6 Hz, J2
= 2.8 Hz, 2H), 7.03 (dt, J1 = 7.6 Hz, J2 = 1.6 Hz,
1H), 7.18 (dd, J1 = 7.6 Hz, J2 = 1.6 Hz, 1H), 7.23–
7.28 (m, 1H), 7.31–7.49 (m, 5H); 13C NMR (100 MHz,
CDCl3)δ 11.5, 35.3, 125.2, 125.2, 127.5, 128.3, 128.7,
129.0, 130.4, 131.8, 132.3, 138.8, 140.5, 148.7, 174.0;
IR (KBr) 2970, 2923, 2870 cm−1 (CH), 1633 cm−1
(C N); MS (m/z) 239 (M+); Anal. Calcd for C15H13NS:
C, 75.27; H, 5.47; N, 5.85. Found: C, 74.98; H, 5.49;
N, 5.52.
Reaction of 9H-thioxanthen-9-ols 2 with MSH
To a solution of 9H-thioxanthen-9-ols 2 (300 mg) in
40 ml of CH2Cl2 at 0◦C was added slowly 1.1 equiv of
O-mesitylenesulfonylhydroxylamine (MSH) in 6 ml
of CH2Cl2. The solution was warmed to room tem-
perature and the reaction was monitored by TLC.
When the reaction had been complete, the solution
was evapolated, and then the residue was purified
by recrystallization or silica-gel column chromatog-
raphy.
11-Phenyl-dibenzo[b,f][1,4]thiazepine (6e) [2]
Yield 57%; mp 117◦C (Ref [2a] 118◦C); 1H NMR (400
MHz, CDCl3) δ 7.06–7.10 (m, 1H), 7.19 (dd, J1 = 7.6
Hz, J2 = 1.2 Hz, 1H), 7.26–7.50 (m, 8H), 7.56 (dd, J1 =