The Journal of Organic Chemistry
Article
2H), 7.85 (d, J = 7.2 Hz, 2H), 7.68−7.60 (m, 4H), 7.58−7.51 (m,
1H), 7.47−7.35 (m, 3H), 6.75 (s, 1H); 13C{1H} NMR (100 MHz,
CDCl3) δ 184.1, 159.8, 152.0, 148.8, 139.2, 138.4, 135.6, 131.5, 130.0,
129.5, 128.5, 127.4, 127.3, 125.5, 124.4, 86.5; ESI-HRMS m/z calcd
for C22H16N3O3S [M + H]+ 402.0907, found 402.0909.
(Z)-2-[5-(3-Methoxyphenyl)-3-phenyl-1,3,4-thiadiazol-2(3H)-yli-
dene]-1-phenylethan-1-one. Compound 3f [112 mg, 97% yield, Rf =
0.48 (5:1 PE/EA)] was isolated as a yellow solid: mp 156−157 °C;
1H NMR (400 MHz, CDCl3) δ 7.88 (d, J = 6.8 Hz, 2H), 7.64 (d, J =
7.6 Hz, 2H), 7.59 (t, J = 7.6 Hz, 2H), 7.53−7.32 (m, 7H), 7.00 (d, J =
5.6 Hz, 1H), 6.72 (s, 1H), 3.83 (s, 3H); 13C{1H} NMR (100 MHz,
CDCl3) δ 183.7, 160.1, 160.0, 154.6, 139.5, 138.8, 131.0, 130.8, 130.2,
129.8, 129.1, 128.3, 127.2, 125.5, 119.3, 117.3, 111.2, 85.7, 55.4; ESI-
HRMS m/z calcd for C23H19N2O2S [M + H]+ 387.1162, found
387.1162.
128.4, 127.3, 126.7, 125.8, 123.4, 86.0; ESI-HRMS m/z calcd for
C22H16ClN2OS [M + H]+ 391.0666, found 391.0668.
(Z)-1-(4-Methoxyphenyl)-2-[3-phenyl-5-(p-tolyl)-1,3,4-thiadiazol-
2(3H)-ylidene]ethan-1-one. Compound 3m [119 mg, 99% yield, Rf =
0.35 (5:1 PE/EA)] was isolated as a yellow solid: mp 120−121 °C;
1H NMR (400 MHz, CDCl3) δ 7.86 (d, J = 8.8 Hz, 2H), 7.78 (d, J =
8.0 Hz, 2H), 7.68−7.57 (m, 4H), 7.54−7.47 (m, 1H), 7.28 (d, J = 7.6
Hz, 2H), 6.90 (d, J = 8.8 Hz, 2H), 6.68 (s, 1H), 3.83 (s, 3H), 2.41 (s,
3H); 13C{1H} NMR (100 MHz, CDCl3) δ 182.8, 162.0, 159.6, 154.7,
141.2, 139.6, 131.6, 129.8 (2C), 129.1, 128.9, 126.9, 126.6, 125.5,
113.5, 85.2, 55.3, 21.5; ESI-HRMS m/z calcd for C24H21N2O2S [M +
H]+ 401.1318, found 401.1316.
(Z)-1-(4-Bromophenyl)-2-[3-phenyl-5-(p-tolyl)-1,3,4-thiadiazol-
2(3H)-ylidene]ethan-1-one. Compound 3n [133 mg, 99% yield, Rf =
0.26 (20:1 PE/EA)] was isolated as a yellow solid: mp 213−214 °C;
1H NMR (400 MHz, CDCl3) δ 7.76 (d, J = 7.6 Hz, 2H), 7.72 (d, J =
8.0 Hz, 2H), 7.66−7.56 (m, 4H), 7.54−7.47 (m, 3H), 7.26 (d, J = 8.0
Hz, 2H), 6.62 (s, 1H), 2.40 (s, 3H); 13C{1H} NMR (100 MHz,
CDCl3) δ 182.3, 160.5, 155.2, 141.5, 139.4, 137.8, 131.5, 129.9, 129.2,
128.8, 126.8, 126.7, 125.7, 125.6, 85.3, 21.6 (1C peak is merged with
other peaks); ESI-HRMS m/z calcd for C23H18BrN2OS [M + H]+
449.0318, found 449.0319.
(Z)-2-[5-(2-Fluorophenyl)-3-phenyl-1,3,4-thiadiazol-2(3H)-ylidene]-
1-phenylethan-1-one. Compound 3g [110 mg, 98% yield, Rf = 0.46 (3:1
1
PE/EA)] was isolated as a yellow solid: mp 178−179 °C; H NMR
(400 MHz, CDCl3) δ 8.02 (t, J = 7.6 Hz, 1H), 7.88 (d, J = 7.2 Hz,
2H), 7.67−7.55 (m, 4H), 7.50 (t, J = 7.2 Hz, 1H), 7.45−7.32 (m,
4H), 7.24−7.14 (m, 2H), 6.71 (s, 1H); 13C{1H} NMR (100 MHz,
CDCl3) δ 183.6, 160.5 (d, J = 7.0 Hz) 160.0 (d, J = 252.9 Hz), 149.8
(d, J = 5.5 Hz), 139.3, 138.8, 132.3 (d, J = 8.4 Hz), 131.0, 129.8,
129.1, 128.6 (d, J = 2.4 Hz), 128.3, 127.2, 125.5, 124.6 (d, J = 3.3
Hz), 117.8 (d, J = 11.7 Hz), 116.6 (d, J = 21.2 Hz), 85.6; 19F{1H}
NMR (376 MHz, CDCl3) δ −111.8; ESI-HRMS m/z calcd for
C22H16FN2OS [M + H]+ 375.0962, found 375.0962.
(Z)-2-[3-Phenyl-5-(p-tolyl)-1,3,4-thiadiazol-2(3H)-ylidene]-1-(pyri-
din-3-yl)ethan-1-one. Compound 3o [102 mg, 92% yield, Rf = 0.18
1
(2:1 PE/EA)] was isolated as a yellow solid: mp 134−135 °C; H
NMR (400 MHz, CDCl3) δ 9.02 (s, 1H), 8.64 (d, J = 3.2 Hz, 1H),
8.19 (dt, J = 8.0, 2.0 Hz, 1H), 7.78 (d, J = 8.0 Hz, 2H), 7.67−7.58 (m,
4H), 7.56−7.50 (m, 1H), 7.35 (dd, J = 8.0, 4.8 Hz, 1H), 7.28 (d, J =
8.0 Hz, 2H), 6.65 (s, 1H), 2.41 (s, 3H); 13C{1H} NMR (100 MHz,
CDCl3) δ 181.2, 160.7, 155.3, 151.4, 148.5, 141.6, 139.2, 134.9, 134.3,
129.9 (2C), 129.4, 126.7, 126.6, 125.5, 123.5, 85.5, 21.6; ESI-HRMS
m/z calcd for C22H18N3OS [M + H]+ 372.1165, found 372.1165.
(Z)-1-[3-Phenyl-5-(p-tolyl)-1,3,4-thiadiazol-2(3H)-ylidene]propan-2-
one. Compound 3p [85 mg, 92% yield, Rf = 0.27 (5:1 PE/EA)] was
(Z)-2-[5-(Naphthalen-2-yl)-3-phenyl-1,3,4-thiadiazol-2(3H)-yli-
dene]-1-phenylethan-1-one. Compound 3h [112 mg, 92% yield, Rf = 0.5
1
(5:1 PE/EA)] was isolated as a yellow solid: mp 148−149 °C; H
NMR (400 MHz, CDCl3) δ 8.29 (s, 1H), 8.02 (d, J = 8.4 Hz, 1H),
7.95−7.80 (m, 5H), 7.68 (d, J = 7.8 Hz, 2H), 7.61 (t, J = 7.8 Hz, 2H),
7.57−7.48 (m, 3H), 7.48−7.37 (m, 3H), 6.76 (s, 1H); 13C{1H} NMR
(100 MHz, CDCl3) δ 183.7, 160.0, 154.7, 139.5, 138.9, 134.3, 133.0,
131.1, 129.8, 129.0, 128.9, 128.6, 128.3, 127.9, 127.6, 127.2 (2C),
127.1, 127.0, 125.5, 123.1, 85.9; ESI-HRMS m/z calcd for
C26H19N2OS [M + H]+ 407.1213, found 407.1215.
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isolated as a yellow solid: mp 179−180 °C; H NMR (400 MHz,
CDCl3) δ 7.74 (d, J = 7.6 Hz, 2H), 7.59−7.52 (m, 4H), 7.50−7.43
(m, 1H), 7.25 (d, J = 8.0 Hz, 2H), 6.00 (s, 1H), 2.39 (s, 3H), 2.16 (s,
3H); 13C{1H} NMR (100 MHz, CDCl3) δ 190.4, 158.3, 154.3, 141.2,
139.5, 129.8, 129.7, 128.9, 127.0, 126.7, 125.5, 88.7, 28.6, 21.6; ESI-
HRMS m/z calcd for C18H17N2OS [M + H]+ 309.1056, found
309.1056.
Ethyl (Z)-5-(2-Oxo-2-phenylethylidene)-4-phenyl-4,5-dihydro-1,3,4-
thiadiazole-2-carboxylate. Compound 3i [99 mg, 94% yield, Rf =
0.41 (5:1 PE/EA)] was isolated as a yellow solid: mp 165−166 °C;
1H NMR (400 MHz, CDCl3) δ 7.84 (d, J = 6.8 Hz, 2H), 7.63−7.51
(m, 5H), 7.47−7.36 (m, 3H), 6.71 (s, 1H), 4.47 (q, J = 7.2 Hz, 2H),
1.42 (t, J = 7.2 Hz, 3H); 13C{1H} NMR (100 MHz, CDCl3) δ 184.3,
160.8, 158.9, 146.4, 138.7, 138.2, 131.4, 129.9, 129.8, 128.4, 127.3,
125.7, 87.2, 63.0, 14.2; ESI-HRMS m/z calcd for C19H17N2O3S [M +
H]+ 353.0954, found 353.0954.
(Z)-2-[5-(tert-Butyl)-3-phenyl-1,3,4-thiadiazol-2(3H)-ylidene]-1-phe-
nylethan-1-one. Compound 3j [98 mg, 97% yield, Rf = 0.14 (10:1 PE/
EA)] was isolated as a yellow solid: mp 128−129 °C; 1H NMR (400
MHz, CDCl3) δ 7.86 (d, J = 6.0 Hz, 2H), 7.60−7.51 (m, 4H), 7.47−
7.33 (m, 4H), 6.66 (s, 1H), 1.45 (s, 9H); 13C{1H} NMR (100 MHz,
CDCl3) δ 183.5, 166.7, 160.7, 139.6, 139.2, 130.8, 129.7, 128.7, 128.2,
127.1, 125.4, 85.1, 35.8, 30.0; ESI-HRMS m/z calcd for C20H21N2OS
[M + H]+ 337.1369, found 337.1370.
(Z)-1-Phenyl-2-[3-(p-tolyl)-1,4,2-oxathiazol-5-ylidene]ethan-1-one.
Compound 5a [81 mg, 91% yield, Rf = 0.33 (10:1 PE/EA)] was
1
isolated as a white solid: mp 117−118 °C; H NMR (400 MHz,
CDCl3) δ 8.01 (d, J = 6.8 Hz, 2H), 7.71 (d, J = 8.0 Hz, 2H), 7.58−
7.46 (m, 3H), 7.31 (d, J = 8.0 Hz, 2H), 7.17 (s, 1H), 2.43 (s, 3H);
13C{1H} NMR (100 MHz, CDCl3) δ 186.4, 176.2, 160.8, 143.1,
137.5, 132.6, 130.2, 128.8, 127.9, 127.8, 123.2, 90.9, 21.7; ESI-HRMS
m/z calcd for C17H14NO2S [M + H]+ 296.0740, found 296.0745.
(Z)-2-[3-(4-Methoxyphenyl)-1,4,2-oxathiazol-5-ylidene]-1-phenyle-
than-1-one. Compound 5b [84 mg, 90% yield, Rf = 0.31 (5:1 PE/EA)]
was isolated as a white solid: mp 100−101 °C; 1H NMR (400 MHz,
CDCl3) δ 8.00 (d, J = 7.6 Hz, 2H), 7.75 (d, J = 8.4 Hz, 2H), 7.50 (m,
3H), 7.15 (s, 1H), 6.99 (d, J = 8.4 Hz, 2H), 3.86 (s, 3H); 13C{1H}
NMR (100 MHz, CDCl3) δ 186.4, 176.2, 162.8, 160.3, 137.6, 132.5,
129.6, 128.7, 127.8, 118.3, 114.9, 90.8, 55.6; ESI-HRMS m/z calcd for
C17H14NO3S [M + H]+ 312.0689, found 312.0694.
(Z)-1-Phenyl-2-[5-phenyl-3-(p-tolyl)-1,3,4-thiadiazol-2(3H)-ylidene]-
ethan-1-one. Compound 3k [106 mg, 95% yield, Rf = 0.22 (10:1 PE/
EA)] was isolated as a yellow solid: mp 149−150 °C; 1H NMR (400
MHz, CDCl3) δ 7.94−7.86 (m, 4H), 7.51 (d, J = 8.4 Hz, 2H), 7.47−
7.35 (m, 8H), 6.70 (s, 1H), 2.46 (s, 3H); 13C{1H} NMR (100 MHz,
CDCl3) δ 183.6, 160.2, 154.5, 139.2, 138.9, 136.9, 131.0, 130.7, 130.3,
129.7, 129.1, 128.3, 127.2, 126.6, 125.3, 85.7, 21.3; ESI-HRMS m/z
calcd for C23H19N2OS [M + H]+ 371.1213, found 371.1216.
(Z)-2-[3-(3-Chlorophenyl)-5-phenyl-1,3,4-thiadiazol-2(3H)-ylidene]-
1-phenylethan-1-one. Compound 3l [114 mg, 97% yield, Rf = 0.2 (10:1
(Z)-1-Phenyl-2-(3-phenyl-1,4,2-oxathiazol-5-ylidene)ethan-1-one.
Compound 5c [75 mg, 89% yield, Rf = 0.31 (10:1 PE/EA)] was
isolated as a white solid: mp 92−93 °C; 1H NMR (400 MHz, CDCl3)
δ 8.01 (d, J = 7.2 Hz, 2H), 7.83 (d, J = 7.2 Hz, 2H), 7.59−7.46 (m,
6H), 7.19 (s, 1H); 13C{1H} NMR (100 MHz, CDCl3) δ 186.5, 176.0,
160.9, 137.5, 132.6, 132.4, 129.5, 128.8, 128.0, 127.8, 126.2, 91.0;
ESI-HRMS m/z calcd for C16H12NO2S [M + H]+ 282.0583, found
282.0588.
(Z)-2-[3-(4-Chlorophenyl)-1,4,2-oxathiazol-5-ylidene]-1-phenylethan-
1-one. Compound 5d [80 mg, 84% yield, Rf = 0.44 (10:1 PE/EA)]
was isolated as a yellow solid: mp 122−123 °C; 1H NMR (400 MHz,
CDCl3) δ 8.00 (d, J = 7.6 Hz, 2H), 7.77 (d, J = 8.0 Hz, 2H), 7.60−
7.45 (m, 5H), 7.20 (s, 1H); 13C{1H} NMR (100 MHz, CDCl3) δ
1
PE/EA)] was isolated as a yellow solid: mp 165−166 °C; H NMR
(400 MHz, CDCl3) δ 7.91−7.84 (m, 4H), 7.68 (t, J = 2.0 Hz, 1H),
7.57 (dt, J = 8.0, 1.6 Hz, 1H), 7.51 (t, J = 8.0 Hz, 1H), 7.48−7.37 (m,
7H), 6.74 (s, 1H); 13C{1H} NMR (100 MHz, CDCl3) δ 184.0, 159.6,
155.0, 140.5, 138.7, 135.5, 131.2, 131.0, 130.7, 129.4, 129.2, 129.1,
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J. Org. Chem. 2021, 86, 5265−5273