684
A. O. Abdelhamid
Vol 46
(10 mL) was heated under reflux for 4 h. The resulting solid
was collected and recrystallized from the proper solvent gave
products 3a–c, 4, 5, 7, 13–15.
Ethyl 6-(1-benzofuran-2-yl)-2-methylnicotinate (14). This
compound was obtained as colorless crystals (EtOH), mp 129–
130ꢀC, yield (37%); IR (cmꢁ1): 1715 (CO), 1639 (C¼¼N),
1581 (C¼¼C). 1H NMR (CD3)2SO d ¼ 1.29 (t, 3H, J ¼ 7.5
Hz, CH3), 2.77 (s, 3H, CH3), 4.26 (q, 2H, J ¼ 7.5 Hz, CH2),
7.27–839 (m, 7H, aromatic protons). 13C NMR (CD3)2SO d ¼
14.2, 25.6, 60.8, 106.3, 111.5, 115.4, 121, 123.3, 125.2, 125.6,
128.3, 139.4, 148, 145.2, 156.2, 159.3, 164. 1H NMR
(CD3)2SO. Anal. Calcd. for C17H15NO3 (281.31): C, 72.58; H,
5.37; N, 4.98. Found: C, 72.45; H, 5.45; N, 4.75.
5-Benzofuran-2-yl-2-phenylpyrazolo[1,5-a]pyrimidine (3a).
This compound was obtained as yellow crystals (AcOH), mp
204–206ꢀC, yield (73%); IR (cmꢁ1): 1635 (C¼¼N), 1589
1
(C¼¼C). H NMR (CD3)2SO d ¼ 7.35–8.55 (m, aromatic pro-
tons). 13C NMR (CD3)2SO d ¼ 102.23, 110.21, 122.6, 122.8,
123.52, 125.8, 125.9, 128.2, 128.6, 130, 131.2, 132, 133.1,
135.2, 140.1, 144.2, 146.2, 147.8. Anal. Calcd. for C20H13N3O
(311.35): C, 77.16; H, 4.21; N, 13.50. Found: C, 76.92; H,
4.00; N, 13.65.
Ethyl 6-(1-benzofuran-2-yl)-2-oxo-1,2-dihydro-pyridine-3-
carboxylate (15). This compound was obtained as colorless
crystals (AcOH), mp 182–184ꢀC, yield (89%); IR (cmꢁ1):
5-(1-Benzofuran-2-yl)-3-methyl-2-phenylpyrazolo[1,5-a]
pyrimidine (3b). This compound was obtained as yellow crys-
tals (AcOH), mp 215–217ꢀC, yield (75%); IR (cmꢁ1): 3050
(CH, aromatic), 2920 (CH, aliphatic), 1635 (C¼¼N), 1589
1
3448 (NH), 1681 (CO), 1635 (C¼¼N), 1589 (C¼¼C). H NMR
(CD3)2SO d ¼ 1.32 (t, 3H, J ¼ 6 Hz, CH3), 4.28 (q, 2H, J ¼
6 Hz, CH2), 7.22–8.50 (m, 7H, aromatic protons), 9.26 (s, br.,
1H, NH). Anal. Calcd. for C16H13NO4 (283.28): C, 67.84; H,
4.63; N, 4.94. Found: C, 67.58; H, 4.50; N, 5.24.
1
(C¼¼C). H NMR (CD3)2SO d ¼ 2.51 (s, 3H, CH3), 7.35–8.55
(m, 12 H, aromatic protons). Anal. Calcd. for C21H15N3O
(325.37): C, 77.52; H, 4.65; N, 12.91. Found: C, 77.45; H,
4.56; N, 13.12.
Synthesis of 8a,b, 9b-d. A mixture of 7(1.3 g, 10 mmol)
and potassium hydroxide (0.6 g, 10 mmol) in N,N-dimethylfor-
mamide (20 mL) was stirred for 2 h at room temperature. The
appropriate of x-bromoacetophenone, methyl iodide, chloroa-
cetone, ethyl chloroacetate, or chloroacetonitrile (10 mmol
each) was added and stirring was continued for 2 h. The
resulting solid was collected and recrystallized from the proper
solvent to give 8a, 8b, and 9b–d, respectively.
5-Benzofuran-2-yl-2-cyanopyrazolo[1,5-a]pyrimidine (3c).
This compound was obtained as pale yellow crystals (AcOH),
mp 238–240ꢀC, yield (76 %); IR (cmꢁ1): 3050 (CH, aromatic),
2920 (CH, aliphatic), 2229 (CN), 1635 (C¼¼N), 1589 (C¼¼C).
1H NMR (CD3)2SO d ¼ 7.32–8.91 (m, 11 H, aromatic pro-
tons), 8.97 (s, 1H, pyrazole H-5). 13C NMR (CD3)2SO d ¼
84.1, 104.2, 112,3, 121.3, 122.6, 123.3, 128.5, 130.1, 130.7,
131.2, 136.2, 140.4, 148.8, 150, 152.2. Anal. Calcd. for
C15H8N4O (260.26): C, 69.23; H, 3.10; N, 21.53. Found: C,
69.32; H, 3.00; N, 21.35.
6-(1-Benzofuran-2-yl)-2-[(2-oxopropyl)thio]nicotino-nitrile
(8a). This compound was obtained as pale yellow crystals
(EtOH), mp 240–242ꢀC, yield (92%); IR (cmꢁ1): IR: 2190
1
(CN). H NMR (CD3)2SO d ¼ 4.09 (S, 2H, SCH2) and 7.47–
8.04 (m, 12H, ArH’s). 1H NMR (CD3)2SO d ¼ 52.8, 95.1,
106.3, 111.4, 113.2, 116, 121.2, 123.3, 125.6, 126.4, 127.6,
127.9, 130.1, 136.7, 151, 155.4, 160.3, 163.2, 198.8. Anal.
Calcd. for C22H14N2O2S (370.42): C, 71.33; H, 3.81; N, 7.56;
S, 8.66. Found: C, 71.23; H, 3.75; N, 7.64; S, 8.65.
2-(1-Benzofuran-2-yl)pyrimido[1,2-a]benzimidazole (4).
This compound was obtained as pale yellow crystals (AcOH),
mp 230–262ꢀC, yield (64%); IR (cmꢁ1): 1616 (C¼¼N), 1562
1
(C¼¼C). H NMR (CD3)2SO d ¼ 7.36–7.955 (m, 5H, aromatic
protons), 8.59 (s, 1H, triazole H-5), 8.99–9.01(d, J ¼ 6H), py-
rimidine ring). Anal. Calcd. for C13H8N4O (236.23): C, 66.10;
H, 3.41; N, 23.72. Found: C, 66.25; H, 3.51; N, 23.54.
6-(1-Benzofuran-2-yl)-2-(methylthio)nicotinonitrile (8b).
This compound was obtained as pale brown crystals (EtOH),
1
mp 120–121ꢀC, yield (81%); IR (cmꢁ1): 2198 (CN). H NMR
7-(1-Benzofuran-2-yl)[1,2,4]triazolo[4,3-a]pyrimidine (5).
This compound was obtained as yellow crystals (AcOH), mp
205–207ꢀC, yield (37%); IR (cmꢁ1): 3050 (CH, aromatic),
(CD3)2SO d ¼ 2.47 (s, 3H, CH3), 6.67–8.02 (m, 11H, aromatic
proton), 8.21 (s, 1H, 5-H of the pyridinethione ring). Anal.
Calcd. for C15H10N2OS (266.32): C, 67.65; H, 3.78; N, 10.52;
S, 12.04. Found: C, 67.52; H, 3.82; N, 10.67; S, 12.19.
1-[3-Amino-6-(1-benzofuran-2-yl)thieno[2,3-b]pyridin-2-yl]
ethanone (9b). This compound was obtained as pale yellow
crystals (EtOH), mp 260–262ꢀC, yield (37%); IR (cmꢁ1):
3316, 3124 (NH2), 1596 (CO). 1H NMR (CD3)2SO d ¼ 2.38
(s, 3H, CH3CO), 6.45 (br, 2H, NH2), 7.16–7.73 (m, 6H, aro-
matic protons), 7.82 (s, 1H, 5-H of the thienopyridine ring).
13C NMR (CD3)2SO d ¼ 30.1, 106.4, 111.6, 115.4, 121.3,
122.6, 123.2, 125.6, 127.4, 127.8, 134.6, 148.2, 149.4, 154.3,
155.8, 156.6, 191.2. Anal. Calcd. for C17H12N2O2S (308.35):
C, 66.22; H, 3.92; N, 9.08; S, 10.40. Found: C, 66.10; H, 3.85;
N, 8.89; S, 10.30.
1
1635 (C¼¼N), 1589 (C¼¼C). H NMR (CD3)2SO d ¼ 7.34–8.53
(m, aromatic protons). Anal. Calcd. for C18H11N3O (285.31):
C, 75.78; H, 3.89; N, 14.73. Found: C, 75.87; H, 3.98; N,
14.65.
6-Benzofuran-2-yl-2-sulfanylpyridine-3-carbonitrile (7).
This compound was obtained as page crystals (EtOH), mp
200–202ꢀC, yield (84%); IR (cmꢁ1): 3342 (NH), 2217 (CN).
1H NMR (CD3)2SO d ¼ 6.67–7.42 (m, 6H, aromatic proton),
8.21 (s, 1H, 5-H of the pyridinethione ring), 14.10 (b, 1H,
SH). Anal. Calcd. for C14H8N2OS (252.30): C, 66.65; H, 3.20;
N, 11.10.60; S, 12.71. Found: C, 66.72; H, 3.41; N, 11.28; S,
12.64.
1-[6-(1-Benzofuran-2-yl)-2-methylpyridin-3-yl]ethanone (13).
This compound was obtained as colorless crystals (EtOH), mp
113–114ꢀC, yield (37%); IR (cmꢁ1): 1685 (CO), 1639 (C¼¼N),
Ethyl 3-amino-6-(1-benzofuran-2-yl)thieno[2,3-b]pyridine-
2-carboxylate (9c). This compound was obtained as pale yel-
low crystals (Dioxan), mp 240–242ꢀC, yield (68%); IR
1
1581 (C¼¼C). H NMR (CD3)2SO d ¼ 2.50 (s, 3H, CH3), 2.70
(s, 3H, CH3), 7.31–8.38 (m, 7H, aromatic protons). 13C NMR
(CD3)2SO d ¼ 24.4, 25.3, 106.3, 111.5, 118.4, 121.2, 123.4,
125, 128.2131, 137.5, 148.2, 151.3, 145,5, 155.8, 199.8. Anal.
Calcd. for C16H13NO2 (251.25): C, 76.48; H, 5.21; N, 5.57.
Found: C, 76.64, H, 5.10; N, 5.75.
1
(cmꢁ1): 3481, 3351 (NH2), 1731 (CO). H NMR (CD3)2SO d
¼ 1.29 (t, 3H, J ¼ 7 Hz, CH3), 4.24 (q, 2H, J ¼ 7 Hz, CH2),
6.21 (br, 2H, NH2), 7.12–7.87 (m, 6H, aromatic protons), 7.99
(s, 1H, 5-H of the thienopyridine ring). 13C NMR (CD3)2SO d
¼ 13.8, 59.1, 105.6, 106.2, 111.4, 115.5, 121.2, 123.5, 125.4,
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet