12
F. Ujjainwalla et al. / Tetrahedron xxx (2015) 1e19
(1H, dd, J 8.1 and 1.1, H-4), 7.43 (1H, dd, J 8.4 and 1.0, H-1), 7.53e7.62
(2H, complex signal, H-3, H-10), 7.76 (1H, ddd, J 8.4, 7.0 and 1.4, H-
2), 8.27e8.31 (2H, complex signal, H-8, H-9), 8.56 (1H, dd, J 7.9 and
1.6, H-7); dC (100.6 MHz): 40.2 (CH3N), 119.4 (CH), 124.5 (C), 125.9
(CH), 127.4 (CH), 127.6 (CH), 128.2 (CH), 130.2 (CH), 130.5 (CH), 133.6
(C),135.3 (CH),141.2 (C),142.3 (C),165.2 (C). m/z: 209 (Mþ,100),178,
166, 152, 139. Found (M)þ 209.0844. C14H11NO requires (M)
209.0841.
From 6d. Column chromatography (petrol/CH2Cl2 1:1) fur-
nished, N-methyl-2-(2,4,6-trimethylphenyl)aniline, 7d (65%) as
white needles (mp 46e48 ꢀC, ether). nmax (film)/cmꢂ1 3406, 2915,
1598, 1575, 1429, 1312, 1270, 1159, 745. dH (400 MHz): 1.97 (6H, s,
CH3), 2.32 (3H, s, CH3), 2.75 (3H, s, CH3N), 3.3 (1H, br s, NH), 6.67
(1H, dd, J 8.0 and 0.8, H-6), 6.75 (1H, ddd, J 7.5, 7.3 and 0.8, H-4),
6.86 (1H, dd, J 7.3 and 1.5, H-3), 6.95 (2H, s, H-30, H-50), 7.25 (1H,
ddd, J 8.0, 7.5 and 1.5, H-5); dC (100.6 MHz): 20.0 [2 CH3eC20 (60)],
21.0 (CH3Ar), 30.7 (CH3N), 109.6 (CH), 117.0 (CH), 125.9 (C), 128.2
(CH), 128.4 (2CH), 129.4 (CH), 134.7 (C), 136.9 (C), 137.2 (2C), 146.0
(C). m/z: 226 (Mþ1, 57), 225 (Mþ, 100), 224 (20), 208 (18), 194 (10).
Found (M)þ 225.1512. C16H19N requires (M) 225.1517.
From 6e. Column chromatography (petrol/CH2Cl2 1:1) fur-
nished, in order of elution, 2-(4-fluorophenyl)-N-methylaniline, 7e
(21%) as a white crystalline solid (mp 60e61 ꢀC, CH2Cl2). nmax (film)/
cmꢂ1 3491, 2913, 1599, 1576, 1498, 1459, 1424, 1314, 1284, 1221,
1157,1005, 837, 746. dH (250 MHz): 2.81 (3H, s, CH3N), 3.86 (1H, br s,
NH), 6.70 (1H, d, J 8.1, H-6), 6.77 (1H, ddd, J 7.7, 7.7 and 1.1, H-4), 7.06
(1H, dd, J 7.3 and 1.7, H-3), 7.14 (2H, m, H-30, H-50), 7.28 (1H, ddd, J
7.7, 7.7 and 1.5, H-5), 7.39 (2H, m, H-20, H-60). m/z: 201 (Mþ), 185,
183, 170, 157, 149, 133. Found (M)þ 201.0960. C13H12FN requires (M)
201.0954, starting material, 6e (26%) and 2-fluoro-6-methyl-6H-
dibenzo[c,e][1,2]thiazine-5,5-dioxide, 8e (34%) as white crystals (mp
131e133 ꢀC, CH2Cl2/petrol). nmax (KBr)/cmꢂ1 1586, 1481, 1442, 1414,
1328, 1294, 1271, 1171, 1119, 1059, 905, 763, 715. dH (250 MHz): 3.46
(3H, s, CH3N), 7.18e7.40 (3H, complex signal, H-3, H-7 and H-8 or H-
9), 7.54 (1H, ddd, J 7.7, 7.7 and 1.4, H-8 or H-9), 7.62 (1H, dd, J 10.0
and 2.3, H-1), 7.94 (1H, dd, J 7.7 and 1.1, H-10), 8.01 (1H, dd, J 8.8 and
5.5, H-4). m/z: 263 (Mþ), 232, 198, 182, 170, 167, 158, 149, 143, 133.
Found (M)þ 263.0422. C13H10FNO2S requires (M) 263.0416.
From 6f. Column chromatography (petrol/CH2Cl2 1:1) furnished,
in order of elution, 2-(4-methoxyphenyl)-N-methylaniline, 7f (29%)
as a colourless oil.42 Found C 78.9, H 6.8, N 6.5. C14H15NO requires C
78.8, H 7.1, N 6.6%. nmax (film)/cmꢂ1 3426, 2922, 1603, 1504, 1243,
1171,1035, 748. dH (400 MHz): 2.80 (3H, s, CH3N), 3.86 (3H, s, CH3O),
4.01 (1H, br s, NH), 6.70 (1H, dd, J 8.0 and 1.0, H-6), 6.78 (1H, ddd, J
7.5, 7.2 and 1.2, H-4), 6.98 (2H, m, H-30, H-50), 7.08 (1H, dd, J 7.5 and
1.8, H-3), 7.26 (1H, ddd, J 8.0, 7.5 and 1.5, H-5), 7.35 (2H, m, H-20, H-
60); dC (100.6 MHz): 30.7 (CH3N), 55.2 (CH3O), 109.6 (CH), 114.1
(2CH), 116.7 (CH), 125.3 (C), 128.4 (CH), 129.9 (CH), 130.4 (2CH),
131.5 (C), 146.3 (C), 158.7 (C). m/z: 214 (Mþ1, 71), 213 (Mþ, 100), 212
(16), 199 (17), 167 (11), 112 (14). Found (M)þ 213.1159. C14H15NO
requires (M) 213.1154, starting material, 6f (34%) and 2-methoxy-6-
methyl-6H-dibenzo[c,e][1,2]thiazine-5,5-dioxide, 8f (10%) as white
crystals (mp 105e106 ꢀC, ether). nmax (KBr)/cmꢂ1 1592, 1444, 1312,
1168,1121, 891, 743, 553. dH (400 MHz): 3.43 (3H, s, CH3N), 3.94 (3H,
s, CH3O), 7.04 (1H, m, H-7), 7.22e7.40 (2H, complex signal, H-3, H-
8), 7.39 (1H, d, J 2.1, H-1), 7.51 (1H, ddd, J 9.0, 8.0 and 1.4, H-9), 7.93
(1H, d, J 8.6, H-4), 7.95 (1H, dd, J 8.0 and 1.8, H-10); dC (100.6 MHz):
32.5 (CH3N), 55.6 (CH3O), 110.2 (CH), 113.8 (CH), 119.3 (CH), 123.7
(C), 124.5 (CH), 124.6 (CH), 125.4 (CH), 126.8 (C), 130.5 (CH), 134.3
(C), 139.7 (C), 162.5 (C). m/z: 276 (Mþ1, 98), 275 (Mþ, 42), 228 (13),
212 (72), 211 (100), 210 (88), 197 (76), 196 (68), 183 (33), 181 (28),
180 (21), 168 (37), 167 (47), 154 (16), 153 (17), 152 (14), 136 (14).
Found (MþH)þ 276.0685. C14H14NO3S requires (MþH) 276.0694.
From 6g. Column chromatography (CH2Cl2/petrol 3:1 to 1:0,
then CH2Cl2/methanol 99:1) furnished, in order of elution, and
inseparable mixture of 2-(3,4-dimethoxyphenyl)-N-methylaniline,
7g, and 8g, which was resolved by HPLC and 6g (24%). Compound
7g (33%) as white prisms (mp 95e96 ꢀC, petrol/CH2Cl2). nmax (film)/
cmꢂ1 3415, 2933, 1504, 1249, 1169. dH (400 MHz): 2.79 (3H, s,
CH3N), 3.87 (3H, s, CH3O), 3.91 (3H, s, CH3O), 4.00 (1H, br s, NH),
6.67 (1H, d, J 8.2, H-6), 6.75 (1H, dt, J 7.5 and 1.1, H-4), 6.91e6.94
(3H, complex signal, H-20, H-50, H-60), 7.08 (1H, dd, J 7.6 and 1.5, H-
3), 7.25 (1H, dt, J 8.1 and 1.6, H-5); dC (100.6 MHz): 30.8 (CH3N), 55.9
(2CH3O), 109.8 (CH), 111.4 (CH), 112.6 (CH), 116.7 (CH), 121.4 (CH),
127.4 (C), 128.6 (CH), 129.9 (CH), 131.9 (C), 146.2 (C), 148.1 (C), 149.1
(C). m/z: 243 (Mþ), 84 (100), 86 (100). Found (M)þ 243.1253.
C15H17NO2 requires (M) 243.1259; 1,2-dimethoxy-6-methyl-6H-
dibenzo[c,e][1,2]thiazine-5,5-dioxide, 8g (8%) as a clear oil. nmax
(film)/cmꢂ1 2941, 1456, 1325, 1264, 1147. dH (400 MHz): 3.35 (3H, s,
CH3N), 3.71 (3H, s, CH3O), 3.97 (3H, s, CH3O), 7.08 (1H, d, J 8.7, H-3),
7.27e7.32 (2H, complex signal, H-7, H-8 or H-9), 7.46 (1H, dt, J 7.5
and 1.5, H-8 or H-9), 7.75 (1H, d, J 8.7, H-4), 8.61 (1H, dd, J 7.9 and
1.5, H-10); dC (100.6 MHz): 32.8 (CH3N), 56.3 (CH3O), 60.4 (CH3O),
111.6 (CH), 119.4 (CH), 119.5 (CH), 122.6 (C), 124.6 (CH), 126.0 (C),
128.3 (C), 129.9 (CH), 130.1 (CH), 139.5 (C), 146.3 (C), 156.6 (C). m/z
(EI): 305 (Mþ), 290, 149 (100). Found (MþH)þ 306.0803.
C
15H16NO4S requires (MþH) 306.0800.
From 6h. Column chromatography (CH2Cl2) furnished, in order
of elution, 2-(2,5-dimethoxyphenyl)-N-methylaniline, 7h (63%) as an
oil. nmax (film)/cmꢂ1 3428, 2935, 1603, 1579, 1494, 1460, 1313, 1267,
1224, 1047, 807, 749. dH (270 MHz): 2.81 (3H, s, CH3), 3.71 (3H, s,
CH3O), 3.78 (3H, s, CH3O), 6.71e6.80 (2H, complex signal, H-3, H-5),
6.82 (1H, d, J 2.7, H-60), 6.88 (1H, dd, J 9.0 and 2.7, H-40), 6.94 (1H, d, J
9.0 and 1.5, H-30), 7.08 (1H, dd, J 7.6 and 1.7, H-4), 7.28 (1H, dt, J 7.6
and 1.7, H-6); dC (67.5 MHz): 30.7 (CH3N), 55.5 (CH3O), 56.4 (CH3O),
109.8 (CH), 112.8 (CH), 113.7 (CH), 116.5 (CH), 117.1 (CH), 124.4 (C),
128.6 (CH), 129.0 (C), 130.3 (CH), 146.7 (C), 151.0 (C), 153.8 (C). m/z:
243 (Mþ), 212 (100), 197, 168. Found (M)þ 243.1261. C15H17NO2
requires (M) 243.1259, and 6h (26%).
From 6i. Column chromatography (CH2Cl2/petrol 1:1 to 1:0,
then petrol/ethyl acetate 8:2) furnished, in order of elution, methyl
3-(2-methylaminophenyl)benzoate, 7i (28%) as white prisms (mp
93e95 ꢀC, petrol/CH2Cl2). nmax (film)/cmꢂ1 3423, 2950, 1722, 1511,
1462, 1305,1260,1231. dH (270 MHz): 2.80 (3H, s, CH3N), 3.92 (3H, s,
CH3O), 6.71 (1H, d, J 8.5, H-30), 6.79 (1H, t, J 7.3, H-50), 7.08 (1H, dd, J
7.3 and 1.5, H-60), 7.29 (1H, ddd, J 8.5, 7.8 and 1.7, H-6), 7.51 (1H, t, J
7.6, H-5), 7.62 (1H, td, J 7.6 and 1.5, H-4), 8.02 (1H, td, J 7.8 and 1.7, H-
4), 8.10 (1H, t, J 1.7, H-2); dC (67.5 MHz): 30.7 (CH3N), 52.0 (CH3O),
109.9 (CH), 116.8 (CH), 126.4 (C), 128.3 (CH), 128.9 (CH), 129.1 (CH),
129.9 (CH), 130.5 (CH), 130.7 (C), 133.9 (CH), 139.7 (C), 145.9 (C),
166.8 (C). m/z: 367 (Mþ), 266, 241 (100). Found (M)þ 241.1103.
C15H15NO2 requires (M) 241.1103, methyl 6-methyl-6H-dibenzo[c,e]
[1,2]thiazine-5,5-dioxide-3-carboxylate, 8i (37%) as white prisms
(mp 178e180 ꢀC, petrol/CH2Cl2). nmax (KBr)/cmꢂ1 1720, 1292, 1166.
dH (270 MHz): 3.46 (3H, s, CH3N), 3.97 (3H, s, CH3O), 7.30e7.37 (2H,
complex signal, H-10, H-8 or H-9), 7.54 (1H, dt, J 7.3 and 1.7, H-8 or
H-9), 8.00e8.04 (2H, complex signal, H-1, H-7), 8.33 (1H, dd, J 8.3
and 2.0, H-2), 8.65 (1H, d, J 2.0, H-4); dC (67.5 MHz): 32.7 (CH3N),
52.5 (CH3O),119.4 (CH), 123.2 (C), 124.0 (CH), 124.8 (CH), 125.6 (CH),
126.0 (CH), 129.8 (C), 131.4 (CH), 132.9 (C), 134.2 (C), 136.2 (C), 139.9
(C), 169.4 (C). m/z (EI): 303 (Mþ, 100), 272, 238, 208, 180. Found
(M)þ 303.0576. C15H13NO4S requires (M) 303.0565, and methyl
(4aRS,10bRS)-4a,10b-dihydro-6-methyl-6H-dibenzo[c,e][1,2]thiazine-
5,5-dioxide-1-carboxylate, 32 (11%) as a clear oil. nmax (film)/cmꢂ1
2948, 1707, 1335, 1138. dH (270 MHz): 3.38 (3H, s, CH3N), 3.91 (3H, s,
CH3O), 4.30 (1H, td, J 8.0 and 2.0, H-4a), 4.81 (1H, d, J 7.8, H-10b),
6.16 (1H, ddd, J 9.5, 2.0 and 1.0, H-4), 6.26 (1H, ddd, J 9.5, 5.1 and 2.7,
H-3), 6.98 (1H, d, J 8.1, HeAr), 7.00e7.02 (2H, complex signal,
HeAr), 7.22e7.30 (2H, complex signal, HeAr); dC (67.5 MHz): 32.2
(CH), 34.3 (CH3N), 52.5 (CH), 57.3 (CH3O), 117.1 (CH), 123.7 (CH),
124.9 (C), 125.9 (CH), 127.5 (CH), 128.1 (CH), 128.3 (CH), 129.1 (C),
134.3 (CH), 140.6 (C), 166.9 (C). m/z (CI): 323 ðMNHþ4 Þ, 224 (100).