1-[1-(4-N,N-Dimethylaminophenyl)-2-(1,1,1-trimethylsilyl)-
ethyl]-1H-1,2,3-benzotriazole (12f). Orange solid (67%), mp
107–108 ЊC. Found: C, 67.81; H, 7.98; N, 16.33. C19H26N4Si
required: C, 67.41; H, 7.76; N, 16.55%; δH 0.06 (9H, s), 2.21
(2H, dd, J = 8.3 Hz, J = 14.4 Hz), 3.03 (6H, s), 6.15 (1H, t,
J = 8.3 Hz), 6.82 (2H, d, J = 8.6 Hz), 7.48–7.59 (4H, m), 7.65
(1H, d, J = 8.2 Hz), 8.17 (1H, d, J = 8.2 Hz); δC Ϫ1.7, 23.1,
40.0, 60.9, 110.2, 111.9, 119.5, 123.3, 126.4, 127.5, 127.8, 131.9,
146.2, 149.9.
7.19–7.25 (4H, m), 7.55 (2H, d, J = 9.0 Hz), 8.00 (1H, d, J = 7.0
Hz); δC 0.2, 21.0, 31.0, 55.3, 77.5, 112.5, 113.4, 119.9, 123.7,
127.0, 128.0, 128.1, 128.9, 132.1, 133.5, 136.5, 138.2, 146.7,
163.0, 194.5.
General procedure for synthesis of compounds 3, 4 and 9
The corresponding starting material 1 (1 mmol) was dissolved
in dry DMF (2 cm3), CsF (0.18 g, 1.5 mmol) added and the
reaction mixture heated at reflux. The reaction was monitored
by GC and the reaction time varied between 40 min and 3 h.
Upon completion, the reaction mixture was diluted with ethyl
acetate (30 cm3), washed with water, dried over magnesium
sulfate, and concentrated to yield crude product as a mixture of
isomers. The mixture was subjected to column chromatography
(hexanes–ethyl acetate, 9:1) to afford the corresponding
mixture of isomers.
General procedure for synthesis of compounds 1a–f
The corresponding starting material 12 (1 mmol) was dissolved
in THF (25 cm3) and cooled to Ϫ78 ЊC. n-BuLi (0.61 cm3, 1.53
M in hexanes) was added to the mixture over 5 min. After
stirring for 30 min, the corresponding benzoyl chloride (1.1
mmol) was added and the reaction mixture was brought to
room temperature overnight. The reaction mixture was diluted
with ethyl acetate (100 cm3) and quenched with a saturated
aqueous solution of ammonium sulfate (50 cm3). The organic
layer was separated, dried over magnesium sulfate and concen-
trated. The resulting residue was subjected to column chrom-
atography (hexanes–ethyl acetate, 4:1) to yield the correspond-
ing product.
1-Phenyl-2-(4-fluorophenyl)prop-2-en-1-one (3b). Oil (28%),
δH 5.64 (1H, s), 6.05 (1H, s), 7.04 (2H, m), 7.31 (4H, m), 7.44
(1H, m), 7.88 (2H, d, J = 7.4 Hz); δC 115.43 (d, J = 21.8 Hz),
121.32, 128.45, 128.72 (d, J = 8.8 Hz), 129.00, 129.96, 133.16,
137.06, 147.14, 161.21 (d, J = 246.8 Hz), 190.35; HRMS Calc.
for C15H11FO: 226.0793. Found: 226.0730.
[2-13C]-(1H-1,2,3-Benzotriazol-1-yl)-1,2-diphenyl-3-(1,1,1-
trimethylsilyl)propan-1-one (1a). Colorless oil (91%), δH 0.12
(9H, s), 2.44 (2H, br s), 7.28 (1H, d, J = 8.0 Hz), 7.46–7.84
(12H, m), 8.31 (1H, d, J = 8.0 Hz); δC 1.2, 32.5 (d, J = 35.0 Hz),
79.4, 114.8, 121.9, 126.3, 128.0, 130.1, 131.0, 132.0, 134.1, 140.6
(d, J = 47.8 Hz), 148.4, 198.0 (d, J = 42.7 Hz); HRMS Calc. for
C24H25N3OSi: 282.1845. Found: 282.1455.
1-(4-Methoxyphenyl)-2-(4-fluorophenyl)prop-2-en-1-one (3d).
Oil (47 %), δH 3.79 (3H, s), 5.48 (1H, s), 5.89 (1H, s), 6.83-6.98
(4H, m), 7.31–7.36 (2H, m), 7.83 (2H, d, J = 8.7 Hz); δC 55.4,
113.7, 115.4 (d, J = 21.7 Hz), 119.2, 128.5 (d, J = 8.3 Hz), 132.4,
133.3, 147.3, 161.2 (d, J = 246.8 Hz), 163.8, 196.0; HRMS Calc.
for C16H13FO2: 257.0977. Found: 257.0975.
1-(4-Methoxyphenyl)-2-(4-methylphenyl)prop-2-en-1-one (3e).
Colorless oil (72%), δH 2.31 (3H, s), 3.80 (3H, s), 5.48 (1H, s),
5.93 (1H, s), 6.87 (2H, d, J = 8.8 Hz), 7.12 (2H, d, J = 8.0 Hz),
7.30 (2H, d, J = 8.2 Hz), 7.90 (2H, d, J = 8.8 Hz); δC 21.0, 55.3,
113.5, 117.6, 126.5, 129.2 (2C), 129.8, 132.2, 134.2, 138.1, 148.3,
163.6, 196.3; HRMS Calc. for C17H16O2: 252.1150. Found:
252.1135.
2-(1H-1,2,3-Benzotriazol-1-yl)-1-phenyl-2-(4-fluorophenyl)-3-
(1,1,1-trimethylsilyl)propan-1-one (1b). Colorless oil (67%).
Found: C, 68.66; H, 5.98; N, 9.80. C24H24FN3OSi required: C,
69.03; H, 5.81; N, 10.07%; δH Ϫ0.03 (9H, s), 2.61 (2H, q, J = 7.1
Hz), 7.11–7.51 (m, 10H), 7.62 (2H, d, J = 7.2 Hz), 8.17 (1H, d,
J = 8.0 Hz); δC 0.2, 30.9, 77.0, 112.0, 115.5 (d, J = 21.5 Hz),
120.1, 123.9, 127.4, 128.4 (d, J = 8.5 Hz), 129.9, 130.0, 132.7,
133.2, 134.8 (d, J = 3.2 Hz), 146.7, 162.2 (d, J = 249.5 Hz),
196.0.
1-(Dimethylamino)-2-(4-N,N-dimethylaminophenyl)propan-1-
one (3f). Orange solid (96%), mp 64–65 ЊC. Found: C, 71.26; H,
8.33; N, 12.84. C13H18N2O required: C, 71.52; H, 8.33; N,
12.84%; δH 2.89 (3H, s), 2.94 (6H, s), 3.05 (3H, s), 5.09 (1H, s),
5.53 (1H, s), 6.65 (2H, d, J = 8.2 Hz), 7.27 (2H, d, J = 8.2 Hz);
δC 34.27, 38.25, 40.02, 109.05, 111.93, 123.12, 126.30, 144.77,
150.25, 171.37.
2-(1H-1,2,3-Benzotriazol-1-yl)-1-(4-fluorophenyl)-2-phenyl-3-
(1,1,1-trimethylsilyl)propan-1-one (1c). Oil (89%), δH Ϫ0.02
(9H, s), 2.58 (2H, d, J = 7.1 Hz), 7.04 (2H, t, J = 8.5 Hz), 7.17
(1H, d, J = 8.5 Hz), 7.35–7.52 (7H, m), 7.71–7.76 (2H, m), 8.22
(1H, d, J = 7.1 Hz); δC 0.1, 30.8, 77.5, 112.2, 115.1 (d, J = 21.5
Hz), 120.1, 123.9, 127.3, 127.8 (d, J = 8.5 Hz), 128.3, 128.4,
129.4, 132.1, 132.2 (d, J = 3.2 Hz), 138.84, 146.63, 163.27, (d,
J = 249.5 Hz), 194.50; HRMS Calc. for C24H24FN3OSi:
417.1673. Found: 417.1693.
[2-13C]-1,2-Diphenyl-3-(1H-1,2,3-benzotriazol-1-yl)propan-1-
one (4a). White solid (24%), δH 4.85–4.92 (1H, m), 5.36–
5.44 (1H, m), 5.55 (1H, dt, J = 132.5 Hz, J = 7.0 Hz),
7.21–7.48 (10H, m), 7.83–8.01 (4H, m); δC 53.9, 54.2 (d,
J = 18.8 Hz), 109.7, 119.6, 123.6, 127.2, 128.1, 128.5, 128.8,
129.4, 129.4, 133.4, 135.5 (d, J = 41.0 Hz), 145.4, 196.8 (d,
J = 40.2 Hz); HRMS Calc. for C21H17N3O: 329.1483. Found:
329.1491.
2-(1H-1,2,3-Benzotriazol-1-yl)-1-(4-methoxyphenyl)-2-(4-
fluorophenyl)-3-(1,1,1-trimethylsilyl)propan-1-one (1d). Glassy
oil (88%). Found: C, 67.27; H, 6.03; N, 9.30; C25H26FN3O2Si
required: C, 67.08; H, 5.87; N, 9.39%; δH Ϫ0.09 (9H, s), 2.26
(1H, d, J = 2.8 Hz), 2.54 (1H, d, J = 2.8 Hz), 3.88 (3H, s), 6.74
(2H, d, J = 8.9 Hz), 7.08–7.14 (3H, m), 7.28–7.41 (m, 4H), 7.62
(2H, d, J = 8.9 Hz), 8.13 (1H, d, J = 8.5 Hz); δC 0.2, 31.1, 55.3,
76.9, 112.1, 113.5, 114.9 (d, J = 21.4 Hz), 120.1, 123.9, 127.4,
130.0 (d, J = 8.2 Hz), 133.9 (d, J = 3.4 Hz), 134.4, 146.4, 160.1
(d, J = 247.5 Hz), 164.3, 196.1.
(E)-[3-13C]-1,3-Diphenylprop-2-en-1-one (9a). Yellow solid
(72%), mp 50–51 ЊC, δH 7.26 (1H, s), 7.39–7.65 (9H, m), 8.03
(2H, d, J = 8.2 Hz); δC 122.1 (d, J = 70.5 Hz), 128.4, 128.5,
128.6, 128.9, 129.0, 130.7, 132.1, 134.3, 135.2, 137.5 (d, J = 73.5
Hz), 144.8, 190.6; HRMS Calc. for C15H12O ϩ Hϩ: 210.1044.
Found: 210.1023.
2-(1H-1,2,3-Benzotriazol-1-yl)-1-(4-methoxyphenyl)-2-(4-
methylphenyl)-3-(1,1,1-trimethylsilyl)propan-1-one (1e). Oil
(93%). Found: C, 70.02; H, 6.65; N, 9.43. C26H29N3OSi required:
C, 70.39; H, 6.59; N, 9.47%; δH Ϫ0.20 (9H, s), 2.33 (3H, s), 2.36
(1H, d, J = 14.8 Hz), 2.54 (1H, d, J = 14.8 Hz), 3.74 (3H, s), 6.68
(2H, d, J = 9.0 Hz), 6.98–7.01 (1H, m), 7.13 (2H, d, J = 8.0 Hz),
(E)-1-Phenyl-3-(4-fluorophenyl)prop-2-en-1-one (9b). White
solid (56%), mp 82–83 ЊC, δH 7.11 (2H, t, J = 8.5 Hz), 7.43–7.66
(6H, m), 7.78 (1H, d, J = 15.8 Hz), 8.03 (2H, d, J = 7.5 Hz);
δC 115.9 (d, J = 21.8 Hz), 121.9, 128.5, 128.6, 130.3 (d, J = 8.8
Hz), 131.2 (d, J = 3.5 Hz), 132.8, 138.2, 143.5, 164.4 (d,
J = 249.7 Hz), 190.3.
J. Chem. Soc., Perkin Trans. 2, 1998, 2515–2518
2517