Page 7 of 9
The Journal of Organic Chemistry
4H); 13C{1H} NMR (75 MHz, Chloroform-d) δ 144.7, 142.6,
135.6, 130.3, 129.1, 127.6, 126.9, 126.6, 119.8, 99.2, 73.7, 9.1,
0.3; HRMS (ESI-TOF) m/z: [M + H]+ calcd for C14H12N,
194.0970; found, 194.0966.
5-(2-cyclopropylethynyl)-1,3-benzoxazole (4m)
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The same general procedure was followed. Column
chromatography (silica gel, eluting with 0-100%
dichloromethane/heptanes gradient) afforded the desired
product as a yellow oil (745 mg, 81%). 1H NMR (300 MHz,
Chloroform-d) δ 8.07 (s, 1H), 7.79 (d, J = 0.9 Hz, 1H), 7.46
(dd, J = 8.5, 0.7 Hz, 1H), 7.40 (dd, J = 8.5, 1.5 Hz, 1H), 1.53 –
1.38 (m, 1H), 0.94 – 0.75 (m, 4H); 13C{1H} NMR (75 MHz,
Chloroform-d) δ 153.2, 149.4, 140.2, 129.6, 123.9, 120.8, 110.9,
93.1, 75.3, 8.7, 0.2; HRMS (ESI-TOF) m/z: [M + H]+ calcd
for C12H10NO, 184.0762; found, 184.0758.
5-(2-cyclopropylethynyl)-1,3-benzothiazole (4n)
The same general procedure was followed. Column
chromatography (silica gel, eluting with 0-100%
EtOAc/heptanes gradient) afforded the desired product as
a yellow oil (883 mg, 95%). 1H NMR (300 MHz,
Chloroform-d) δ 8.87 (d, J = 1.6 Hz, 1H), 8.08 (d, J = 1.7 Hz,
1H), 7.70 (d, J = 8.4 Hz, 1H), 7.38 – 7.29 (m, 1H), 1.47 – 1.32
(m, 1H), 0.77 (ddq, J = 6.5, 3.0, 2.0, 1.6 Hz, 4H); 13C{1H}
NMR (75 MHz, Chloroform-d) δ 154.6, 153.1, 132.8, 128.7,
126.4, 121.9, 121.4, 93.9, 75.2, 8.5, 0.1; HRMS (ESI-TOF) m/z:
[M + H]+ calcd for C12H10NS, 200.0534; found, 200.0528.
6-(2-cyclopropylethynyl)-2-methyl-indazole (4o)
The same general procedure was followed. Column
chromatography (silica gel, eluting with 0-100%
dichloromethane/heptanes gradient) afforded the desired
product as a brown oil (874 mg, 94%). 1H NMR (300 MHz,
Chloroform-d) δ 7.79 (s, 1H), 7.72 (d, J = 1.3 Hz, 1H), 7.50
(dd, J = 8.7, 0.9 Hz, 1H), 7.03 (dd, J = 8.7, 1.3 Hz, 1H), 4.16
(s, 3H), 1.47 (tt, J = 8.0, 5.2 Hz, 1H), 0.85 (tt, J = 8.0, 2.5 Hz,
4H); 13C{1H} NMR (75 MHz, Chloroform-d) δ 148.8, 135.1,
131.3, 128.4, 125.2, 123.8, 121.2, 120.6, 119.9, 93.2, 76.7, 40.5,
8.7, 0.4; HRMS (ESI-TOF) m/z: [M + H]+ calcd for
C13H13N2, 197.1079, found, 197.1075.
3-(2-cyclopropylethynyl)-1,5-naphthyridine (4h)
The same general procedure was followed. Column
chromatography (silica gel, eluting with 0-100%
EtOAc/heptanes gradient) afforded the desired product as
a brown solid (744 mg, 80%). 1H NMR (300 MHz,
Chloroform-d) δ 8.87 – 8.75 (m, 2H), 8.22 (dt, J = 4.6, 2.2
Hz, 2H), 7.45 (dd, J = 8.6, 4.2 Hz, 1H), 1.42 (td, J = 8.2, 4.0
Hz, 1H), 0.82 (tt, J = 8.1, 2.7 Hz, 4H); 13C{1H} NMR (75
MHz, Chloroform-d) δ 153.2, 151.6, 143.0, 142.1, 138.7, 137.0,
124.1, 121.7, 99.0, 72.6, 8.9, 0.3; HRMS (ESI-TOF) m/z: [M +
H]+ calcd for C13H11N2, 195.0922; found, 195.0917.
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2-(2-cyclopropylethynyl)pyrazine (4i)
The same general procedure was followed. Column
chromatography
(silica
gel,
eluting
with
heptane/dichloromethane) afforded the desired product
as a brown oil (829 mg, 91%). 1H NMR (300 MHz,
Chloroform-d) δ 8.57 (d, J = 1.5 Hz, 1H), 8.49 – 8.37 (m,
2H), 1.58 – 1.43 (m, 1H), 0.93 (dddd, J = 7.0, 5.6, 2.9, 1.8 Hz,
4H); 13C{1H} NMR (75 MHz, Chloroform-d) δ 147.7, 144.3,
142.3, 140.9, 98.9, 73.1, 9.1, 0.3; HRMS (ESI-TOF) m/z: [M +
H]+ calcd for C9H9N2, 145.0766; found, 145.0762.
3-(2-cyclopropylethynyl)pyridine (4j)
The same general procedure was followed. Column
chromatography (silica gel, eluting with 0-100%
EtOAc/heptanes gradient) afforded the desired product as
a yellow oil (867 mg, 96%). 1H NMR (300 MHz,
Chloroform-d) δ 8.48 (dd, J = 2.1, 0.9 Hz, 1H), 8.33 (dd, J =
4.9, 1.7 Hz, 1H), 7.51 (d, J = 7.9 Hz, 1H), 7.05 (ddd, J = 7.9,
4.9, 0.9 Hz, 1H), 1.41 – 1.26 (m, 1H), 0.82 – 0.65 (m, 4H);
13C{1H} NMR (75 MHz, Chloroform-d) δ 152.2, 147.6, 138.3,
122.7, 120.9, 97.0, 72.4, 8.6, 0.1; HRMS (ESI-TOF) m/z: [M
+ H]+ calcd for C10H10N, 144.0813; found, 144.0809.
6-(2-cyclopropylethynyl)-1-methyl-indazole (4p)
The same general procedure was followed. Column
chromatography (silica gel, eluting with 0-100%
dichloromethane/heptanes gradient) afforded the desired
product as a yellow oil (886 mg, 95%). 1H NMR (300 MHz,
Chloroform-d) δ 7.91 (d, J = 1.0 Hz, 1H), 7.58 (dd, J = 8.4,
0.9 Hz, 1H), 7.42 (d, J = 1.1 Hz, 1H), 7.12 (dd, J = 8.3, 1.2 Hz,
1H), 4.01 (s, 3H), 1.55 – 1.40 (m, 1H), 0.93 – 0.79 (m, 4H);
13C{1H} NMR (75 MHz, Chloroform-d) δ 139.7, 132.8, 124.2,
123.1, 121.8, 120.8, 112.1, 93.9, 76.3, 35.5, 8.8, 0.3; HRMS (ESI-
TOF) m/z: [M + H]+ calcd for C13H13N2, 197.1079; found,
197.1075.
3-(2-cyclopropylethynyl)benzofuran (4k)
The same general procedure was followed. Column
chromatography (silica gel, eluting with 0-100%
dichloromethane/heptanes gradient) afforded the desired
1
product as a colorless oil (550 mg, 59%). H NMR (300
MHz, Chloroform-d) δ 7.77 (d, J = 1.1 Hz, 1H), 7.71 (dt, J =
6.7, 1.4 Hz, 1H), 7.55 – 7.46 (m, 1H), 7.42 – 7.26 (m, 2H),
1.56 (tt, J = 8.1, 5.0 Hz, 1H), 0.92 (ddt, J = 10.4, 4.9, 2.7 Hz,
4H); 13C{1H} NMR (75 MHz, Chloroform-d) δ 154.6, 147.2,
128.1, 125.1, 123.2, 120.5, 111.6, 105.0, 98.1, 64.9, 8.8, 0.5;
HRMS (ESI-TOF) m/z: [M + H]+ calcd for C13H11O,
183.0810; found, 183.0802.
Ethyl
6-(2-cyclopropylethynyl)imidazo[1,2-
a]pyridine-2-carboxylate (4q)
5-(2-cyclopropylethynyl)benzofuran (4l)
The same general procedure was followed. Column
chromatography (silica gel, eluting with 0-100%
EtOAc/heptanes gradient) afforded the desired product as
a white solid (586 mg, 62%). 1H NMR (300 MHz,
Chloroform-d) δ 8.14 (s, 1H), 8.08 (d, J = 0.8 Hz, 1H), 7.53
(d, J = 9.4 Hz, 1H), 7.14 (dd, J = 9.4, 1.6 Hz, 1H), 4.42 (q, J =
7.1 Hz, 2H), 1.49 – 1.33 (m, 4H), 0.94 – 0.72 (m, 4H); 13C{1H}
NMR (75 MHz, Chloroform-d) δ 163.2, 144.0, 137.4, 129.6,
128.5, 118.5, 116.9, 111.6, 96.2, 71.2, 61.3, 14.5, 8.8, 0.2; HRMS
(ESI-TOF) m/z: [M + H]+ calcd for C15H15N2O2, 255.1134;
found, 255.1128.
The same general procedure was followed. Column
chromatography (silica gel, eluting with 0-100%
dichloromethane/heptanes gradient) afforded the desired
product as a yellow oil (520 mg, 56%). 1H NMR (300 MHz,
Chloroform-d) δ 7.69 – 7.57 (m, 2H), 7.46 – 7.38 (m, 1H),
7.34 (dd, J = 8.5, 1.6 Hz, 1H), 6.71 (dd, J = 2.2, 0.9 Hz, 1H),
1.48 (ddt, J = 8.5, 7.7, 5.1 Hz, 1H), 0.92 – 0.79 (m, 4H);
13C{1H} NMR (75 MHz, Chloroform-d) δ 154.3, 145.7, 128.2,
127.5, 124.7, 118.5, 111.4, 106.5, 91.9, 76.0, 8.6, 0.3; HRMS
(ESI-TOF) m/z: [M + H]+ calcd for C13H11O, 183.0810;
found, 183.0803.
3-(2-cyclopropylethynyl)thiophene (4r)
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