8
Q. Yang et al. / Tetrahedron xxx (2015) 1e10
NMR (400 MHz, CDCl3):
d
¼8.49e8.39 (m, 2H), 7.72e7.60 (m, 2H),
7.98e7.87 (m, 2H), 7.72e7.59 (m, 2H), 7.37 (m, 3H), 7.24e7.12 (m,
1H) ppm. 13C NMR (101 MHz, CDCl3):
136.85, 128.97, 128.72, 126.88, 122.08, 120.59 ppm. The spectro-
scopic data is in accordance with literature.41
7.46e7.32 (m, 3H), 6.95e6.85 (m, 2H), 4.11 (q, J¼7.2 Hz, 2H), 3.79 (s,
d¼157.33, 149.50, 139.17,
3H), 2.59 (s, 3H), 0.99 (t, J¼7.2 Hz, 3H) ppm. 13C NMR (100 MHz,
CDCl3):
d
¼168.54, 165.23, 163.53, 163.40, 162.13, 141.51, 138.41,
134.4, 130.34, 129.82, 128.39, 122.57, 113.79, 61.63, 55.33, 22.84,
13.63 ppm. The spectroscopic data is in accordance with
literature.41
4.3.17. 2-(4-Methoxyphenyl)pyridine (3q). White solid (80 mg,
87%); mp 52e53 ꢁC. 1H NMR (400 MHz, CDCl3):
d
¼8.60e8.50 (m,
1H), 7.91e7.81 (m, 2H), 7.65e7.51 (m, 2H), 7.08e7.05 (m, 1H),
4.3.10. Ethyl 2-(4-fluorophenyl)-4-methyl-6-phenylpyrimidine-5-
carboxylate (3j). White solid (131 mg, 78%); mp 94e96 ꢁC. 1H
NMR (400 MHz, CDCl3):
6.93e6.90 (m, 1H), 6.90e6.88 (m, 1H), 3.76 (s, 3H) ppm. 13C NMR
(101 MHz, CDCl3):
121.40, 119.78, 114.13, 55.34 ppm. The spectroscopic data is in ac-
cordance with literature.41
d
¼160.48, 157.12,149.55, 136.65, 132.05, 128.16,
d
¼8.54e8.42 (m, 2H), 7.75e7.57 (m, 2H),
7.49e7.28 (m, 3H), 7.07 (t, J¼8.7 Hz, 2H), 4.12 (q, J¼7.2 Hz, 2H), 2.60
(s, 3H), 1.00 (t, J¼7.2 Hz, 3H) ppm. 13C NMR (100 MHz, CDCl3):
d
¼168.32, 166.13, 165.42, 163.59, 162.68, 138.12, 133.32, 130.82,
4.3.18. 2-p-Tolylpyridine (3r). Clear oil (66 mg, 78%). 1H NMR
130.73, 129.98, 128.45, 128.35, 123.24, 115.52, 115.31, 61.75, 22.80,
13.62 ppm. The spectroscopic data is in accordance with
literature.41
(400 MHz, CDCl3):
d
¼8.57 (d, J¼4.9 Hz, 1H), 7.80 (d, J¼8.1 Hz,
2H), 7.65e7.56 (m, 2H), 7.18 (d, J¼8.1 Hz, 2H), 7.07 (td, J¼5.0,
3.2 Hz, 1H), 2.30 (s, 3H) ppm. 13C NMR (101 MHz, CDCl3):
d
¼157.30, 149.45, 138.80, 136.55, 136.45, 129.36, 126.64, 121.67,
4.3.11. Ethyl 2-(4-chlorophenyl)-4-methyl-6-phenylpyrimidine-5-
120.11, 21.16 ppm. The spectroscopic data is in accordance with
literature.41
carboxylate (3k). White solid (142 mg, 81%); mp 84e86 ꢁC. 1H
NMR (400 MHz, CDCl3):
d
¼8.51e8.36 (m, 2H), 7.80e7.56 (m, 2H),
7.52e7.29 (m, 5H), 4.13 (q, J¼7.2 Hz, 2H), 2.61 (s, 3H), 1.01 (t,
4.4. General experimental procedure for CeC coupling re-
actions between disulfides and terminal alkynes
J¼7.2 Hz, 3H) ppm. 13C NMR (100 MHz, CDCl3):
¼168.25, 165.48,
d
163.63, 162.64, 138.04, 137.29, 135.59, 130.00, 129.96, 128.70,
128.44, 128.41, 123.52, 61.80, 22.80, 13.64 ppm. The spectroscopic
data is in accordance with literature.41
Under argon atmosphere, 1a (0.25 mmol, 136 mg), DPE-Phos
(6 mol %), wool-Pd(OAc)2 complex (30 mg, Pd 1.56 wt %), CuTC
(1.5 mmol, 287 mg) were added into a Schlenk tube dried by Hot-
gun. The tube was stopped and degassed with nitrogen for three
times. Distilled xylene (3 mL), Et3N (0.5 mL), 4a (1 mmol,
122 mg), was added by syringe and the mixture. The reaction
mixture was allowed to stir for approximately 48 h at 120 ꢁC and
the reaction was monitored by TLC analysis. Then the mixture
was added with 2 mL saturated NH4Cl solution to quench the
reaction, the organic components were extracted by acetic ether
and evaporated in vacuum and further purified by column
chromatography on silica gel with petroleum ether/ethanol
(30:1) to give the product 5a as clear crystal. The product was
analyzed by GCeMS or NMR analysis. The conversion and se-
lectivity were determined using GC analysis. All the prepared
compounds are known and were compared with authentic
samples.
4.3.12. Ethyl 4-methyl-6-phenyl-2-(thiophen-2-yl)pyrimidine-5-
carboxylate (3l). White solid (108 mg, 67%); mp 89e91 ꢁC. 1H
NMR (400 MHz, CDCl3):
d
¼8.03 (dd, J¼3.7, 1.1 Hz, 1H), 7.71e7.56 (m,
2H), 7.51e7.28 (m, 4H), 7.07 (dd, J¼4.9, 3.8 Hz, 1H), 4.11 (q, J¼7.2 Hz,
2H), 2.57 (s, 3H), 0.99 (t, J¼7.2 Hz, 3H) ppm. 13C NMR (101 MHz,
CDCl3):
d
¼168.20, 165.54,163.67, 160.49, 142.96, 137.88, 130.54,
130.00, 129.82, 128.42, 128.29, 128.21, 122.77, 61.71, 22.70, 13.61
ppm. The spectroscopic data is in accordance with literature.41
4.3.13. Ethyl 4-methyl-2-(naphthalen-1-yl)-6-phenylpyrimidine-5-
carboxylate (3m). White solid (145 mg, 79%); mp 83e85 ꢁC. 1H
NMR (400 MHz, CDCl3):
d
¼8.62e8.60 (m,1H), 8.06 (dd, J¼7.2,1.2 Hz,
1H), 7.89 (d, J¼8.2 Hz, 1H), 7.87e7.80 (m, 1H), 7.77e7.65 (m, 2H),
7.59e7.31 (m, 6H), 4.18 (q, J¼7.2 Hz, 2H), 2.69 (s, 3H),1.05 (t, J¼7.2 Hz,
3H) ppm. 13C NMR (101 MHz, CDCl3):
d¼168.26, 166.35, 165.29,
163.53, 137.85, 135.41, 134.05, 130.96, 130.73, 130.06, 129.58, 128.55,
128.42, 126.85, 125.85, 125.70, 125.16, 123.18, 109.69, 61.93, 22.86,
13.67 ppm. The spectroscopic data is in accordance with literature.41
4.4.1. Ethyl 4-methyl-6-phenyl-2-(phenylethynyl)pyrimidine-5-
carboxylate (5a). White solid; mp 161e162 ꢁC. 1H NMR (400 MHz,
CDCl3):
4.22e4.17 (q, J¼8.0 Hz, 2H), 2.67 (s, 3H), 1.06 (t, J¼8.0 Hz, 3H) ppm.
13C NMR (100 MHz, CDCl3)
d
¼7.70e7.66 (m, 4H), 7.48e7.39 (m, 3H), 7.38e7.27 (m, 3H),
4.3.14. Methyl 4-methyl-2,6-diphenylpyrimidine-5-carboxylate
d
¼167.53, 165.59, 164.08, 152.38, 137.19,
(3n). White solid (144 mg, 95%). Mp 118e120 ꢁC. 1H NMR
132.85, 132.54, 130.40, 130.01, 129.91, 129.52, 128.75, 126.53, 128.38,
128.17, 124.19, 121.25, 88.53, 88.09, 61.98, 22.47, 13.48 ppm. The
spectroscopic data is in accordance with literature.41
(400 MHz, CDCl3):
d
¼8.67e8.56 (m, 2H), 7.83e7.78 (m, 2H), 7.53
(dd, J¼6.3, 3.1 Hz, 6H), 3.76 (s, 3H), 2.73 (s, 3H) ppm. 13C NMR
(101 MHz, CDCl3):
d
¼169.04, 165.48, 163.82, 138.18, 137.18,
132.33, 131.07, 130.08, 128.68, 128.55, 128.51, 128.39, 123.05,
52.51, 22.91 ppm. The spectroscopic data is in accordance with
literature.41
4.4.2. Ethyl 4-methyl-6-phenyl-2-(p-tolylethynyl)pyrimidine-5-
carboxylate (5b). Yellow oil (150 mg, 88%). 1H NMR (400 MHz,
CDCl3):
d
¼7.65e7.56 (m, 2H), 7.51 (d, J¼8.0 Hz, 2H), 7.45e7.33 (m,
3H), 7.10 (d, J¼7.9 Hz, 2H), 4.12 (q, J¼7.2 Hz, 2H), 2.58 (s, 3H), 2.30 (s,
4.3.15. Methyl 4-isopropyl-2,6-diphenylpyrimidine-5-carboxylate
3H), 0.99 (t, J¼7.2 Hz, 3H) ppm. 13C NMR (100 MHz, CDCl3)
(3o). Clear oil (136 mg, 82%). 1H NMR (400 MHz, CDCl3):
d
¼167.57, 165.54, 164.05, 152.47, 140.17, 137.20, 132.65, 130.16,
d
¼8.69e8.57 (m, 2H), 7.84e7.71 (m, 2H), 7.57e7.44 (m, 6H), 3.71 (s,
129.13, 128.54, 128.29, 124.00, 118.09, 89.07, 87.66, 61.96, 22.61,
21.63, 13.58 ppm. The spectroscopic data is in accordance with
literature.41
3H), 3.28e3.22 (m, 1H), 1.41 (d, J¼6.7 Hz, 6H) ppm. 13C NMR
(101 MHz, CDCl3):
d¼172.95, 169.18, 163.80, 163.28, 138.32, 137.41,
130.93, 129.90, 128.59, 128.49,128.39, 128.30, 122.36, 52.51, 33.43,
21.86 ppm. The spectroscopic data is in accordance with
literature.41
4.4.3. Ethyl 4-methyl-2-(oct-1-ynyl)-6-phenylpyrimidine-5-
carboxylate (5c). Yellow oil (146 mg, 87%). 1H NMR (400 MHz,
CDCl3):
d
¼7.63e7.49 (m, 2H), 7.47e7.28 (m, 3H), 4.10 (q, J¼7.2 Hz,
4.3.16. 2-Phenylpyridine (3p). Clear oil (64 mg, 83%). 1H NMR
2H), 2.54 (s, 3H), 2.40 (t, J¼7.3 Hz, 2H), 1.65e1.53 (m, 2H), 1.43e1.33
(m, 2H),1.28e1.19 (m, 4H), 0.97 (t, J¼7.2 Hz, 3H), 0.81 (t, J¼6.7 Hz,
(400 MHz, CDCl3):
d¼8.95e8.89 (m, 1H), 8.62 (d, J¼4.6 Hz, 1H),