Arkivoc 2019, iii, 0-0
Ko, I. S. et al.
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2-(3,5-Dimethoxyphenyl)-5-phenyl-1,3,4-thiadiazole (5f). White solid; Yield: 85%; mp 144-145 C. H NMR
(300 MHz, CDCl3) δ (ppm) 3.88 (s, 6 H), 6.60 (t, J 2.2 Hz, 1 H), 7.18 (d, J 2.2 Hz, 2 H), 7.47-7.55 (m, 3 H), 8.01
(dd, J 6.6, 2.9 Hz, 2H); 13C NMR (75 MHz, CDCl3) δ (ppm) 55.73, 103.56, 106.02, 128.14, 129.39, 130.35, 131.36,
131.97, 161.42, 168.36 (thiadiazole C), 168.48 (thiadiazole C); HRMS (EI+): m/z Calcd. for C16H14N2O2S+:
298.0776; found: 298.0764
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2-(4-Ethylphenyl)-5-phenyl-1,3,4-thiadiazole (5g). White solid; Yield: 80%; mp 90-91 C. H NMR (300 MHz,
CDCl3) δ (ppm) 1.28 (t, J 7.6 Hz, 3 H), 2.72 (q, J 7.7 Hz, 2 H), 7.33 (d, J 8.3 Hz, 2 H), 7.44-7.57 (m, 3 H), 7.93 (d, J
8.3 Hz, 2 H), 7.97-8.06 (m, 2 H); 13C NMR (75 MHz, CDCl3) δ (ppm) 15.18, 28.75, 127.74, 127.96, 128.02,
128.75, 129.21, 130.35, 131.05, 147.94, 167.84 (thiadiazole C), 168.38 (thiadiazole C) ; HRMS (EI+): m/z Calcd.
for C16H14N2S+: 266.0878; found: 266.0872
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2-(4-Fluorophenyl)-5-(4-methoxyphenyl)-1,3,4-thiadiazole (5h). White solid; Yield: 80%; mp 160-161 C. H
NMR (300 MHz, CDCl3) δ (ppm) 3.89 (s, 3 H) 7.01 (d, J 9.0 Hz, 2 H), 7.19 (t, J 8.6 Hz, 2 H), 7.95 (d, J 8.8 Hz, 2 H),
8.00 (dd, J 8.8, 5.1 Hz, 2 H); 13C NMR (75 MHz, CDCl3) δ (ppm) 55.52, 114.72, 116.32, 116.62, 122.89, 126.77,
126.81, 129.64, 129.90, 130.02, 162.19, 162.84, 166.17, 166.30 (thiadiazole C), 168.18 (thiadiazole C); HRMS
(EI+): m/z Calcd. For C15H11FN2OS+: 286.0576; Found: 286.0576
2-(4-Chlorophenyl)-5-(4-methoxyphenyl)-1,3,4-thiadiazole (5i).34 [CAS No. 17572-63-3]: White solid; Yield:
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85%; mp190-191 C (Lit. 186-187 C]. H NMR (300 MHz, CDCl3) δ (ppm) 3.89 (s, 3 H) 7.01 (d, J 8.8 Hz, 2 H),
7.48 (d, J 8.6 Hz, 2 H), 7.95 (dd, J 8.8, 2.9 Hz, 4 H); 13C NMR (75 MHz, CDCl3) δ (ppm) 55.59, 114.80, 122.91,
129.04, 129.20, 129.64, 129.75, 137.22, 162.31, 166.33 (thiadiazole C), 168.43 (thiadiazole C)
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2-(4-bromophenyl)-5-(4-methoxyphenyl)-1,3,4-thiadiazole (5j). White solid; Yield: 83% ; mp 215 C; H NMR
(300MHz, CDCl3) δ (ppm) 3.89 (s, 3 H) 7.01 (d, J 8.6 Hz, 2 H), 7.63 (d, J 8.4 Hz, 2 H), 7.88 (d, J 8.4 Hz, 2 H), 7.96
(d, J 8.6 Hz, 2 H); 13C NMR (75 MHz, CDCl3) δ (ppm) 55.59, 114.77, 122.85, 125.52, 129.36, 129.73, 132.59,
162.28, 166.41 (thiadiazole C), 168.45 (thiadiazole C); HRMS (EI+): m/z Calcd. For: C15H11BrN2OS+: 345.9775;
Found: 345.9764
2,5-Bis-(4-methoxyphenyl)-1,3,4-thiadiazole (5k)35 [CAS No. 17453-03-1]. White solid; Yield: 78%; mp 167-169
oC[Lit. 170-172 oC]. 1H NMR (300 MHz, CDCl3) δ (ppm) 3.88 (s, 6 H), 7.00 (d, J 8.8 Hz, 4 H), 7.94 (d, J 8.8 Hz, 4 H);
13C NMR (75 MHz, CDCl3) δ (ppm) 55.58, 114.72, 123.28, 129.61, 162.06, 167.40 (thiadiazole C)
2-(3,5-Dimethoxyphenyl)-5-(4-methoxyphenyl)-1,3,4-thiadiazole (5l). Light beige solid; Yield: 75%; mp 134-
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135 C. 1H NMR (300 MHz, CDCl3) δ (ppm) 3.88 (s, 6 H), 3.89 (s, 3 H), 6.59 (t, J 2.3 Hz, 1 H), 7.01 (d, J 8.8 Hz, 2
H), 7.16 (d, J 2.3 Hz, 2 H), 7.95 (d, J 8.8 Hz, 2 H); 13C NMR (75 MHz, CDCl3) δ (ppm) 55.57, 55.72, 103.42, 105.94,
114.74, 123.05, 129.69, 132.13, 161.41, 162.22, 167.56 (thiadiazole C), 168.25 (thiadiazole C); HRMS (EI+): m/z
Calcd. for C17H16N2O3S+: 328.0882; Found: 328.0869
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2-(4-Ethylphenyl)-5-(4-methoxyphenyl)-1,3,4-thiadiazole (5m). White solid; Yield: 85%; mp 101-102 C. H
NMR (300 MHz, CDCl3) δ (ppm) 1.28 (t, J 7.6 Hz, 3 H), 2.72 (q, J 7.5 Hz, 2 H), 3.89 (s, 3 H), 7.01 (d, J 9.0 Hz, 2 H),
7.32 (d, J 8.3 Hz, 2 H), 7.96 (d, J 9.0 Hz, 2 H), 7.92 (d, J 8.3 Hz, 2 H) ; 13C NMR (75 MHz, CDCl3) δ (ppm) 15.35,
28.88, 55.56, 114.68, 123.16, 127.99, 128.07, 128.84, 129.63, 147.85, 162.06, 167.72 (thiadiazole C), 167.76
(thiadiazole C); HRMS (EI+): m/z Calcd. For C17H16N2OS+: 296.0983; Found: 296.1002
Procedure for synthesis of compound (8)27,28
In a round-bottom flask, following flame drying, 40 ml of 1M phenylmagnesium bromide (40 mmol) in THF was
added. It was then cooled to 0 °C, and 2.42 ml of carbon disulfide (40 mmol) was slowly introduced dropwise.
It was stirred at room temperature for 12 hr and then poured into 100 g of ice water and 3.78 g of chloroacetic
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acid (40 mmol). Anhydrous sodium carbonate 3.36g (20 mmol) was added and stirred for 24 hr at 90 C. The
liquid was adjusted to pH 2 with concentrated hydrochloric acid, and a red solid was obtained by
recrystallization in a mixture of ethyl acetate and hexane.
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