Full Paper
General Procedure for the Synthesis of Products 2.
2-(4-ethylphenyl)-1-nitronaphtho[2,1-b]furan (2e)
Light yellow solid, 52 mg, 82% yield; mp 113–1158C. 1H NMR
(400 MHz, CDCl3): d=8.41 (d, J=8.4 Hz, 1H), 7.96 (d, J=8.0 Hz,
1H), 7.88–7.78 (m, 3H), 7.68–7.61 (m, 2H), 7.60–7.54 (m, 1H), 7.36
(d, J=8.0 Hz, 2H), 2.79–2.70 (m, 2H), 1.31 ppm (t, J=7.8 Hz, 3H).
13C NMR (100 MHz, CDCl3): d=152.9, 150.2, 147.7, 131.4, 129.3,
128.6, 128.4, 128.3, 127.4, 125.9, 125.8, 124.7, 124.0, 115.4, 111.9,
29.0, 15.3 ppm. IR (KBr): n˜ =1496, 1392, 1360, 1213, 1116, 1017,
840, 785 cmÀ1. HRMS (APCI-TOF, m/z): calcd for C20H16NO3 [M+H]+
318.1130, found 318.1141.
Example for the synthesis of 2a:
A suspension of AgNO3 (0.1 mmol, 0.5 equiv), tBuONO (0.2 mmol,
1.0 equiv) in 1.0 mL of 1,4-dioxane was stirred at 108C under air
conditions. Subsequently, 1-(phenylethynyl)naphthalen-2-ol 1a
(0.2 mmol, 1.0 equiv) in 1,4-dioxane (1.0 mL) was added into the
suspension over 30 min via a syringe pump. Next, the mixture was
sealed and stirred for 30 min until TLC (petroleum ether: ethyl ace-
tate=1:15, v/v) revealed that conversion of the starting material
1a was completed. The reaction system was evaporated under
vacuum and purified by flash column chromatography (silica gel,
mixtures of petroleum ether/ ethyl acetate=1:50, v/v) to afford
the desired product 2a.
1-nitro-2-(4-propylphenyl)naphtho[2,1-b]furan (2 f)
Light yellow solid, 50 mg, 75% yield; mp 80–828C. 1H NMR
(400 MHz, CDCl3): d=8.41 (d, J=8.4 Hz, 1H), 8.01–7.94 (m, 1H),
7.90–7.84 (m, 1H), 7.82 (d, J=8.0 Hz, 2H), 7.70–7.61 (m, 2H), 7.60–
7.54 (m, 1H), 7.34 (d, J=8.0 Hz, 2H), 2.71–2.64 (m, 1H), 1.76–1.65
(m, 2H), 0.99 ppm (t, J=7.4 Hz, 3H). 13C NMR (100 MHz, CDCl3): d=
152.9, 150.2, 146.2, 131.5, 129.3, 129.0, 128.6, 128.2, 127.4, 125.9,
125.8, 124.8, 124.0, 115.4, 111.9, 38.1, 24.3, 13.9 ppm. IR (KBr): n˜ =
1506, 1383, 1341, 1219, 1187, 1007, 835, 769 cmÀ1. HRMS (APCI-
TOF, m/z): calcd for C21H18NO3 [M+H]+ 332.1287, found 332.1282.
1-nitro-2-phenylnaphtho[2,1-b]furan (2a)
Light yellow solid, 44 mg, 76% yield; mp 104–1058C. 1H NMR
(400 MHz, CDCl3): d=8.40 (d, J=8.4 Hz, 1H), 7.98 (d, J=7.6 Hz,
1H), 7.91–7.85 (m, 3H), 7.70–7.62 (m, 2H), 7.61–7.56 (m, 1H), 7.56–
7.51 ppm (m, 3H). 13C NMR (100 MHz, CDCl3): d=152.4, 150.4,
131.5, 130.9, 129.3, 128.9, 128.8, 128.2, 127.5, 127.4, 125.9, 125.9,
123.9, 115.3, 111.9 ppm. IR (KBr): n˜ =1507, 1453, 1388, 1356, 1200,
1131, 1020, 802, 750 cmÀ1
. HRMS (APCI-TOF, m/z): calcd for
C18H12NO3 [M+H]+ 290.0817, found 290.0835.
2-(4-(tert-butyl)phenyl)-1-nitronaphtho[2,1-b]furan (2g)
Light yellow solid, 44 mg, 63% yield; mp 85–878C. 1H NMR
(400 MHz, CDCl3): d=8.41 (d, J=8.4 Hz, 1H), 7.97 (d, J=8.0 Hz,
1H), 7.89–7.82 (m, 3H), 7.68–7.61 (m, 2H), 7.60–7.52 (m, 3H),
1.39 ppm (s, 9H). 13C NMR (100 MHz, CDCl3): d=154.5, 152.9, 150.2,
131.4, 129.3, 128.6, 128.0, 127.4, 125.9, 125.8, 124.5, 124.0, 115.4,
111.9, 35.1, 31.2 ppm. IR (KBr): n˜ =1573, 1508, 1393, 1357, 1210,
1143, 1014, 827, 802, 754 cmÀ1. HRMS (APCI-TOF, m/z): calcd for
C22H20NO3 [M+H]+ 346.1443, found 346.1429.
1-nitro-2-(p-tolyl)naphtho[2,1-b]furan (2b)
Light yellow solid, 41 mg, 68% yield; mp 116–1188C. 1H NMR
(400 MHz, CDCl3): d=8.41 (d, J=8.4 Hz, 1H), 7.97 (d, J=8.0 Hz,
1H), 7.89–7.83 (m, 1H), 7.79 (d, J=8.0 Hz, 2H), 7.69–7.60 (m, 2H),
7.60–7.54 (m, 1H), 7.33 (d, J=8.0 Hz, 2H), 2.45 ppm (s, 3H).
13C NMR (100 MHz, CDCl3): d=152.9, 150.2, 141.5, 131.4, 129.6,
129.3, 128.6, 128.2, 127.4, 125.9, 125.8, 124.6, 124.0, 115.4, 111.9,
2-(4-ethylphenyl)-1-nitronaphtho[2,1-b]furan (2h)
21.7 ppm. IR (KBr): n˜ =1506, 1389, 1356, 1213, 1015, 801, 736 cmÀ1
HRMS (APCI-TOF, m/z): calcd for C19H14NO3 [M+H]+ 304.0974,
.
Light yellow solid, 35 mg, 55% yield; mp 143–1448C. 1H NMR
(400 MHz, CDCl3): d=8.43 (d, J=8.0 Hz, 1H), 7.97 (d, J=7.6 Hz,
1H), 7.90–7.82 (m, 3H), 7.67–7.61 (m, 2H), 7.59–7.54 (m, 1H), 7.06–
7.01 (m, 2H), 3.89 ppm (s, 3H). 13C NMR (100 MHz, CDCl3): d=
161.7, 153.2, 150.0, 131.5, 130.2, 129.3, 128.4, 127.3, 125.9, 125.7,
124.1, 119.8, 115.5, 114.3, 111.8, 55.5 ppm. IR (KBr): n˜ =1608, 1506,
1389, 1351, 1256, 1176, 1021, 825, 796 cmÀ1. HRMS (APCI-TOF, m/z):
calcd for C19H14NO4 [M+H]+ 320.0923, found 320.0930.
found 304.0981.
1-nitro-2-(m-tolyl)naphtho[2,1-b]furan (2c)
Light yellow solid, 30 mg, 50% yield; mp 139–1418C. 1H NMR
(400 MHz, CDCl3): d=8.40 (d, J=8.4 Hz, 1H), 7.98 (d, J=8.0 Hz,
1H), 7.87 (d, J=9.2 Hz, 1H), 7.71–7.66 (m, 3H), 7.66–7.61 (m, 1H),
7.61–7.55 (m, 1H), 7.45–7.39 (m, 1H), 7.34 (d, J=7.6 Hz, 1H),
2.46 ppm (s, 3H). 13C NMR (100 MHz, CDCl3): d=152.7, 150.3, 138.7,
131.8, 131.4, 129.3, 128.8, 128.7, 128.6, 127.5, 127.3, 125.9, 125.3,
123.9, 115.4, 111.9, 21.5 ppm. IR (KBr): n˜ =1565, 1505, 1392, 1362,
1192, 1089, 1007, 812, 745 cmÀ1. HRMS (APCI-TOF, m/z): calcd for
C19H14NO3 [M+H]+ 304.0974, found 304.0970.
2-(4-fluorophenyl)-1-nitronaphtho[2,1-b]furan (2i)
Light yellow solid, 37 mg, 60% yield; mp 125–1268C. 1H NMR
(400 MHz, CDCl3): d=8.41 (d, J=8.4 Hz, 1H), 7.98 (d, J=7.6 Hz,
1H), 7.93–7.86 (m, 3H), 7.68–7.63 (m, 2H), 7.61–7.56 (m, 1H), 7.26–
7.19 ppm (m, 2H). 13C NMR (100 MHz, CDCl3): d=164.1 (1JCF
=
251.6 Hz), 151.75, 150.32, 131.49, 130.72, 130.64, 129.33, 128.94,
127.55, 125.95, 125.85, 124.01, 123.65, 123.61, 116.2 (2JCF =22.0 Hz),
115.24, 111.81 ppm. IR (KBr): n˜ =1606, 1508, 1362, 1237, 1164, 1102,
831, 795, 752 cmÀ1. HRMS (APCI-TOF, m/z): calcd for C18H11FNO3
[M+H]+ 308.0723, found 308.0719.
2-(3,4-dimethylphenyl)-1-nitronaphtho[2,1-b]furan (2d)
Light yellow solid, 33 mg, 52% yield; mp 120–1218C. 1H NMR
(400 MHz, CDCl3): d=8.40 (d, J=8.4 Hz, 1H), 7.96 (d, J=7.6 Hz,
1H), 7.83 (d, J=8.8 Hz, 1H), 7.67–7.61 (m, 4H), 7.59–7.54 (m, 1H),
7.27 (d, J=8.4 Hz, 1H), 2.35 (s, 3H), 2.34 ppm (s, 3H). 13C NMR
(100 MHz, CDCl3): d=153.1, 150.1, 140.2, 137.3, 131.4, 130.1, 129.3,
129.0, 128.5, 127.4, 125.9, 125.8, 125.7, 124.9, 124.0, 115.4, 111.9,
20.0, 19.9 ppm. IR (KBr): n˜ =1506, 1391, 1359, 1255, 1212, 1180,
2-(3-chloro-4-fluorophenyl)-1-nitronaphtho[2,1-b]furan (2j)
Light yellow solid, 38 mg, 56% yield; mp 152–1548C. 1H NMR
(400 MHz, CDCl3): d=8.39 (d, J=8.4 Hz, 1H), 8.02–7.95 (m, 2H),
7.90 (d, J=8.8 Hz, 1H), 7.83–7.77 (m, 1H), 7.70–7.64 (m, 2H), 7.62–
7.57 (m, 1H), 7.33–7.27 ppm (m, 1H). 13C NMR (100 MHz, CDCl3):
d=159.5 (1JCF =253.8 Hz), 150.5, 150.1, 131.5, 130.9, 129.4, 129.4,
1006, 817, 795, 748 cmÀ1
C20H16NO3 [M+H]+ 318.1130, found 318.1125.
. HRMS (APCI-TOF, m/z): calcd for
&
&
Chem. Asian J. 2019, 00, 0 – 0
4
ꢀ 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
ÝÝ These are not the final page numbers!