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S.O. Rashid et al. / Tetrahedron 75 (2019) 2413e2430
1268, 1196, 911, 794, 770. 1H NMR (400 MHz, CDCl3)
d
2.12 (s, 3 H),
283.0740 (
D
¼ ꢂ4.6 ppm). Microanalysis C12H14N2O4S requires: C,
2.25 (s, 3 H), 2.37 (s, 3 H), 3.63 (br. s., 2 H), 6.59 (d, J ¼ 8.0 Hz, 1 H),
51.05, H, 5.00, N, 9.92, S, 11.36%; found: C, 50.76, H, 5.19, N, 9.81, S,
11.04%.
6.66 (d, J ¼ 1.0 Hz, 1 H), 6.82 (dq, J ¼ 8.0, 1.0 Hz, 1 H). 13C NMR
(100 MHz, CDCl3)
d 10.7, 12.5, 17.3, 112.4, 117.5, 123.2, 128.5, 129.0,
136.1, 137.1, 158.2, 175.6. LRMS (ESþ) C12H14N2O4S requires 282;
found (ESþ) 283 [MþH]þ; HRMS (ESþ) C12H15N2O4S [MþH]þ re-
4.3.6. 2-(((30,50-dimethylisoxazol-40-yl)sulfonyl)oxy)benzene-
diazonium tetrafluoroborate, 4a
quires 283.0312; found 283.0313 (
D
¼ 0.35 ppm).
Using GP3: Starting with amine 3a (1.30 g, 4.85 mmol, 1 eq.),
ethanol (7 mL), isoamyl nitrite (0.782 mL, 5.82 mmol, 1.2 eq.), HBF4
48% (1.64 mL,12.62 mmol, 2.6 eq.). The title compound was obtained
as a colourless amorphous solid. Yield 1.691 g (95%); vmax/cm¡1
(ATR) 3104, 2998, 2290), 1573, 1478, 1442, 1408, 1365, 1313, 1275,
1219, 1204, 1130, 1050, 1036, 853, 782, 733, 688, 651. 1H NMR
4.3.3. Synthesis of 3c
Using GP1: Starting with 3,5-dimethylisoxazole-4-sulfonyl
chloride 1 (1 g, 5.11 mmol, 1 eq.), 1-aminonaphthalen-2-ol hydro-
chloride 2c (1.1 g, 5.62 mmol, 1.1 eq.), NaOH (2 M, 12 mL, 24 mmol).
Recrystallization by CHCl3/petroleum ether gave title compound as
yellow-brown coloured crystalline solid. Yield 1.2 g (72%); mp.
116e117 ꢀC; vmax/cm¡1 (ATR) 3475, 3391, 3066, 3054, 2958, 2929,
1618,1590,1511,1465,1438,1407,1385,1363,1205,1269,1179, 1159,
1129, 1112, 1078, 1036, 976, 871, 707. 1H NMR (400 MHz, CDCl3):
(400 MHz, acetone-d6):
d 2.46 (s, 3 H), 2.72 (s, 3 H), 8.01e8.12 (m,
2 H), 8.54 (td, J ¼ 8.0, 1.0 Hz, 1 H) 8.99 (dd, J ¼ 8.0, 1.0 Hz, 1 H). 13C
NMR (100 MHz, acetone-d6):
d 9.9, 12.4, 109.3, 110.6, 124.1, 129.9,
135.4, 144.6, 148.8, 157.8, 178.6. Microanalysis C11H10BF4N3O4S,
requires: C, 35.99, H, 2.75, N, 11.45, S, 8.73%; found: C, 36.24, H, 2.95,
N, 11.40, S, 8.96%.
d
2.24 (s, 3 H), 2.28 (s, 3 H), 4.31 (br. s., 2 H), 6.91 (d, J ¼ 9.0 Hz, 1 H),
7.08 (d, J ¼ 9.0 Hz, 1 H), 7.35e7.39 (m, 2 H), 7.63e7.69 (m, 2 H). 13C
4.3.7. (((30,50-dimethylisoxazol-40-yl)sulfonyl)oxy)-6-
methylbenzenediazonium tetrafluoroborate, 4b
NMR (100 MHz, CDCl3):
d 10.8, 12.6, 112.6, 118.5, 120.9, 121.2, 124.1,
125.8, 126.6, 128.6, 131.3, 132.8, 135.1, 158.1, 175.7. LRMS (ESþ)
C
C
15H14N2O4S requires 318; found (ESþ) 319 [MþH]þ; HRMS (ESþ)
15H15N2O4S [MþH]þ requires 319.0753; found 319.0765
¼ 3.9 ppm).
Using GP3: Starting with amine 3b (800 mg, 2.83 mmol, 1 eq.),
ethanol (8 mL), isoamyl nitrite (0.46 mL, 3.39 mmol, 1.2 eq.), HBF4
48% (0.96 mL, 7.36 mmol, 2.6 eq.). The title compound was obtained
as colourless amorphous solid. Yield 1.01 g (94%); vmax/cm¡1 (ATR)
3140, 3108, 3082, 2996, 2947, 2266, 1596, 1566, 1479, 1413, 1263,
1212, 1025, 962, 817, 793, 722, 682, 632. 1H NMR (400 MHz,
(D
4.3.4. Synthesis of 3-amino-[1,10-biphenyl]-4-yl 300,500-
dimethylisoxazole-400-sulfonate, 3d
Acetone-d6):
J ¼ 8.0 Hz, 1 H), 7.93 (dt, J ¼ 8.0, 1.0 Hz, 1 H), 8.37 (t, J ¼ 8.0 Hz, 1 H).
13C NMR (100 MHz, acetone-d6):
9.9, 12.4, 18.3, 109.4, 110.7, 121.2,
131.1, 143.5, 148.4, 148.9, 157.8, 178.5. Microanalysis
12H12BF4N3O4S, requires: C, 37.82, H, 3.17, N, 11.03, S, 8.41%; found:
d 2.46 (s, 3 H), 2.73 (s, 3 H), 2.97 (s, 3 H), 7.84 (d,
Using GP1: Starting with 3,5-dimethylisoxazole-4-sulfonyl
chloride 1 (960.08 mg, 4.90 mmol, 1 eq.), 3-amino-[1,10-biphenyl]-
4-ol, 2d (1 g, 5.39 mmol, 1.1 eq.), NaOH (2 M, 12 mL, 24 mmol).
Recrystallization by CH2Cl2/petroleum ether gave the title com-
pound as feint brown-coloured crystalline solid. Yield 1.04 g (62%).
Using GP2: Starting with 3,5-dimethylisoxazole-4-sulfonyl
chloride 1 (1 g, 5.11 mmol, 1.1 eq.), 3-amino-[1,10-biphenyl]-4-ol,
2d (859.46 mg, 4.64 mmol, 1 eq.), Et3N (0.712 mL, 5.11 mmol, 1.1
eq.). Yield 1.59 g (100%); mp. 103e104 ꢀC; vmax/cm¡1 (ATR) 3466,
3377, 3057, 3033, 3012, 1620, 1588, 1512, 1486, 1438, 1408, 1360,
1085, 1383, 1324, 1269, 1234, 1204, 1165, 1038, 913, 867, 829, 761,
d
C
C, 38.00, H, 2.92, N, 11.02, S, 8.21%.
4.3.8. 1-(((3,5-dimethylisoxazol-4-yl)sulfonyl)oxy)naphthalene-2-
diazonium tetrafluoroborate, 4c
Using GP3: Starting with amine 3c (606 mg, 1.9 mmol, 1 eq.),
ethanol (5 mL), isoamyl nitrite (0.307 mL, 2.28 mmol, 1.2 eq.), HBF4
48% (0.64 mL, 4.95 mmol, 2.6 eq.). The title compound was obtained
as yellowish-green coloured amorphous solid. Yield 668 mg (84%);
vmax/cm¡1 (ATR) 3120, 3081, 3069, 2984), 2242, 1625, 1578, 1563,
1510,1405,1368,1273,1245,1227,1207,1174,1126, 1060, 1043, 1019,
695. 1H NMR (400 MHz, CDCl3)
d 2.22 (s, 3 H), 2.31 (s, 3 H), 3.86 (s,
2 H), 6.71e6.76 (m, 1 H), 6.81 (s, 1 H), 6.82 (d, J ¼ 2.0 Hz, 1 H),
7.18e7.23 (m, 1 H), 7.27 (t, J ¼ 7.0 Hz, 2 H), 7.34e7.38 (m, 2 H). 13C
NMR (100 MHz, CDCl3)
d 10.8, 12.6, 112.4, 116.0, 117.3, 123.2, 127.0,
127.8, 128.9, 135.5, 139.9, 140.1, 141.7, 158.2, 175.9. LRMS (ESþ)
979, 873, 851, 833, 766. 1H NMR (400 MHz, acetone-d6):
d 2.52 (s,
C
17H16N2O4S requires 344; found (ESþ) 345 [MþH]þ, 367 [MþNa]þ;
3 H), 2.79 (s, 3 H), 8.06 (ddd, J ¼ 8.0, 7.0, 1.0 Hz, 1 H), 8.20 (d,
J ¼ 9.0 Hz, 1 H), 8.25 (ddd, J ¼ 8.0, 7.0, 1.0 Hz, 1 H), 8.54 (d, J ¼ 8.0 Hz,
1 H), 8.62 (dd, J ¼ 8.0, 1.0 Hz, 1 H), 9.20 (d, J ¼ 9.0 Hz, 1 H). 13C NMR
HRMS (ESþ) C17H17N2O4S [MþH]þ requires 345.0909; found
345.0921 (
D
¼ 3.5 ppm). Microanalysis C17H16N2O4S requires: C,
59.29, H, 4.68, N, 8.13, S, 9.31%; found: C, 59.56, H, 4.67, N, 8.08, S,
9.17%.
(100 MHz, acetone-d6):
d 10.0, 12.5, 111.0, 119.7, 122.3, 126.9, 130.3,
131.3, 134.4, 147.2, 153.8, 157.8, 178.8. Microanalysis
15H12BF4N3O4S, requires: C, 43.19, H, 2.90, N,10.07, S, 7.69%; found:
C
4.3.5. 4-Amino-3-methylphenyl 30,50-dimethylisoxazole-40-
sulfonate, 3e
C, 43.30, H, 3.06, N, 9.98, S, 7.57%.
Using GP1: Starting with 3,5-dimethylisoxazole-4-sulfonyl
chloride 1 (1 g, 5.11 mmol, 1 eq.), 4-amino-3-methylphenol 2e
(692.54 mg, 5.62 mmol, 1.1 eq.), NaOH (2 M, 13 mL, 26 mmol).
Recrystallization by CHCl3/petroleum ether gave the title compound
as light brown-coloured crystalline solid. Yield 1.26 g (88%); mp.
96e97 ꢀC; vmax/cm¡1 (ATR) 3473, 3374, 3083, 2986, 1644, 1586,
1528, 1498, 1438, 1356, 1198, 1306, 1272, 1150, 1117, 1052, 997, 935,
4.3.9. Synthesis of 4-(((3,5-dimethylisoxazol-4-yl)sulfonyl)oxy)-
[1,10-biphenyl]-3-diazonium tetrafluoroborate, 4d
Using GP3: Starting with amine 3d (1.15 g, 3.35 mmol, 1 eq.),
ethanol (4 mL), isoamyl nitrite (0.54 mL, 4.03 mmol, 1.2 eq.), HBF4
48% (1.14 mL, 8.73 mmol, 2.6 eq.). The title compound was obtained
as a yellow-coloured amorphous powder. Yield 1.24 g (97%); vmax
/
cm¡1 (ATR) 3107, 3070, 3056, 3035, 2275, 1586, 1558, 1515, 1480,
917, 874. 1H NMR (400 MHz, CDCl3):
d
2.09 (s, 3 H), 2.30 (s, 3 H), 2.36
1439, 1404, 1367, 1289, 1271, 1235, 1202, 1153, 1129, 1061, 1030, 884,
(s, 3 H), 3.75 (s, 2 H), 6.52e6.56 (m, 1 H), 6.60e6.66 (m, 1 H), 6.74 (d,
852. 1H NMR (400 MHz, acetone-d6):
d 2.49 (s, 3 H), 2.74 (s, 3 H),
J ¼ 2.0 Hz, 1 H). 13C NMR (100 MHz, CDCl3):
d
10.7, 12.4, 17.4, 112.1,
7.53e7.63 (m, 3 H), 7.82e7.88 (m, 2 H), 8.12 (d, J ¼ 9.0 Hz, 1 H),
114.9, 120.4, 123.4, 123.9, 140.4, 144.3, 158.2, 175.4. LRMS (ESþ)
8.77e8.81 (m, 1 H), 9.29 (d, J ¼ 2.0 Hz, 1 H). 13C NMR (100 MHz,
C
12H14N2O4S requires 282; found (ESþ) 283 [MþH]þ, 305 [MþNa]þ;
acetone-d6): d 10.0, 12.4, 109.9, 110.5, 124.5, 127.2, 129.6, 130.0,
HRMS (ESþ) C12H15N2O4S [MþH]þ requires 283.0753; found
132.6, 135.2, 142.2, 142.3, 147.6, 157.8, 178.7. Microanalysis