E. Marchal et al. / Tetrahedron 63 (2007) 9979–9990
9985
87.1, 94.5, 114.0, 115.4, 124.1, 127.5, 130.4, 131.6, 133.7,
133.2, 159.8, 166.8 ppm; IR (film) 2214, 1727 cmꢂ1
HRMS (EI): calcd for C17H14O3: 266.0943; found 266.0944.
1H NMR (CDCl3, 270 MHz) d 1.31 (t, 3H, J¼7.6 Hz),
2.57 (s, 3H), 2.95 (q, 2H, J¼7.6 Hz), 3.94 (s, 3H), 7.07–
7.39 (m, 3H), 7.36 (td, 1H, J¼7.7, 1.3 Hz), 7.49 (td, 1H,
J¼7.7, 1.3 Hz), 7.65 (dd, 1H, J¼7.7, 1.3 Hz), 7.95 (dd,
1H, J¼7.7, 1.3 Hz) ppm; 13C NMR (CDCl3, 67.5 MHz)
d 15.0, 21.1, 27.9, 52.2, 92.1, 95.9, 122.2, 124.1, 125.2,
126.8, 127.6, 128.3, 130.4, 131.4, 131.5, 134.12, 140.9,
146.8, 166.8 ppm; IR (film) 2207, 1731 cmꢂ1; HRMS
(EI): calcd for C19H18O2: 278.1307; found 278.1316.
;
4.1.8.19. 2-((4-Methoxyphenyl)ethynyl)benzoic acid
(8b). White solid; mp 133–135 ꢀC; Rf 0.84 CH2Cl2/MeOH
(90/10)+0.1% CH3COOH; 1H NMR (CDCl3, 270 MHz)
d 3.79 (s, 3H), 6.83 (d, 2H, J¼8.7 Hz), 7.39 (t, 1H,
J¼7.7 Hz), 7.50–7.56 (m, 3H), 7.62 (d, 1H, J¼7.7 Hz),
8.12 (d, 1H, J¼7.7 Hz) ppm; 13C NMR (CDCl3,
67.5 MHz) d 55.2, 86.9, 95.8, 114.1, 115.2, 124.7, 127.6,
130.3, 131.4, 132.5, 133.3, 133.9, 159.9, 171.1 ppm; IR
(KBr) 2962, 2219, 1707 cmꢂ1; HRMS (EI): calcd for
C16H12O3: 252.0786; found 252.0791.
4.1.8.25. 2-((2-Ethyl-6-methylphenyl)ethynyl)benzoic
acid (8e). White solid; mp 121–123 ꢀC; Rf 0.28 Et2O/pen-
tane (30/70)+0.1% CH3COOH; 1H NMR (CDCl3,
270 MHz) d 1.29 (t, 3H, J¼7.6 Hz), 2.55 (s, 3H), 2.94 (q,
2H, J¼7.6 Hz), 7.03–7.05 (m, 2H), 7.18 (t, 1H, J¼7.6 Hz),
7.42 (td, 1H, J¼7.7, 1.3 Hz), 7.56 (td, 1H, J¼7.7, 1.3 Hz),
7.70 (d, 1H, J¼7.7 Hz), 8.14 (d, 1H, J¼7.7 Hz) ppm; 13C
NMR (CDCl3, 67.5 MHz) d 15.0, 21.1, 27.9, 93.5, 95.7,
122.1, 125.2, 126.8, 127.7, 128.5, 129.9, 131.3, 132.6,
134.4, 141.2, 147.1, 171.5 ppm; IR (KBr) 2930, 2204,
1709 cmꢂ1; HRMS (EI): calcd for C18H16O2: 264.1150;
found 264.1148.
4.1.8.20. Methyl 2-((3-fluorophenyl)ethynyl)benzoate
(6c). Yellow oil; Rf 0.48 Et2O/pentane (10/90); H NMR
1
(CDCl3, 270 MHz) d 3.87 (s, 3H), 6.97 (m, 1H), 7.16–7.34
(m, 4H), 7.42 (td, 1H, J¼7.7, 1.3 Hz), 7.55 (d, 1H,
J¼7.7 Hz), 7.90 (d, 1H, J¼7.7 Hz) ppm; 13C NMR
(CDCl3, 67.5 MHz) d 52.2, 89.0, 92.9, 115.8 (d, JF2–C
21 Hz), 118.4 (d, J2F–C¼23 Hz), 123.2, 125.1 (d, J3F–C
¼
¼
9 Hz), 127.6 (d, JF4–C¼3 Hz), 128.2, 129.9 (d,
J3F–C¼9 Hz), 130.5, 131.7, 134.0, 162.4 (d, J1F–C¼247 Hz),
166.5 ppm; IR (film) 2206, 1728 cmꢂ1; HRMS (EI): calcd
for C16H11O2F: 254.0743; found 254.0743.
4.1.8.26. Methyl 2-(o-tolylethynyl)benzoate (6f). Col-
orless oil; Rf 0.40 CH2Cl2/pentane (30/70); 1H NMR
(CDCl3, 270 MHz) d 2.56 (s, 3H), 3.95 (s, 3H), 7.14–7.28
(m, 3H), 7.37 (td, 1H, J¼7.7, 1.4 Hz), 7.46–7.56 (m, 2H),
7.66 (dd, 1H, J¼7.7, 1.4 Hz), 7.97 (dd, 1H, J¼7.7, 1.4 Hz)
ppm; 13C NMR (CDCl3, 67.5 MHz) d 20.7, 52.2, 91.9,
93.4, 123.1, 123.9, 123.1, 123.9, 125.5, 127.7, 128.5,
129.5, 130.4, 131.6, 131.7, 132.2, 134.1, 140.4,
166.8 ppm; IR (film) 2212, 1728 cmꢂ1; HRMS (EI): calcd
for C17H14O2: 250.0994; found 250.0987.
4.1.8.21. 2-((3-Fluorophenyl)ethynyl)benzoic acid
(8c). Rosy solid; mp 125–127 ꢀC; Rf 0.52 Et2O/pentane
(50/50)+0.1% CH3COOH; 1H NMR (CDCl3, 270 MHz)
d 7.01 (m, 1H), 7.20–7.28 (m, 2H), 7.34 (d, 1H,
J¼7.7 Hz), 7.42 (t, 1H, J¼7.7 Hz), 7.55 (t, 1H, J¼7.7 Hz),
7.67 (d, 1H, J¼7.7 Hz), 8.14 (d, 1H, J¼7.7 Hz), 11.83
(s, 1H) ppm; 13C NMR (CDCl3, 67.5 MHz) d 88.9, 93.8
(d, J4F–C¼3 Hz), 115.8 (d, JF2–C¼21 Hz), 118.4 (d, J2F–C
3 Hz), 128.2, 129.9 (d, J3F–C¼9 Hz), 130.6, 131.4, 132.6,
134.2, 162.3 (d, J1F–C¼246 Hz), 171.6 ppm; IR (KBr)
3071, 1702 cmꢂ1; HRMS (EI): calcd for C15H9FO2:
240.0587; found 240.0593.
¼
4.1.8.27. 2-(o-Tolylethynyl)benzoic acid (8f). White
solid; mp 119–121 ꢀC; Rf 0.16 Et2O/pentane (50/50)+0.1%
CH3COOH; H NMR (CDCl3, 270 MHz) d 2.54 (s, 3H),
23 Hz), 124.2, 125.1 (d, J3F–C¼9 Hz), 127.6 (d, JF4–C
¼
1
7.13–7.23 (m, 3H), 7.41 (td, 1H, J¼7.8, 1.3 Hz), 7.51–
7.57 (m, 2H), 7.69 (dd, 1H, J¼7.8, 1.3 Hz), 8.13 (dd, 1H,
J¼7.8, 1.3 Hz) ppm; 13C NMR (CDCl3, 67.5 MHz) d 20.6,
91.7, 94.6, 122.9, 124.8, 125.5, 127.8, 128.6, 129.5, 130.2,
131.3, 132.2, 132.5, 134.4, 140.7, 171.6 ppm; IR (KBr)
2988, 2212, 1692 cmꢂ1; HRMS (EI): calcd for C16H12O2:
236.0837; found 236.0826.
4.1.8.22. Methyl 2-(pyridin-2-ylethynyl)benzoate (6d).
Brown oil; Rf 0.11 AcOEt/pentane (30/70); 1H NMR
(CDCl3, 270 MHz) d 3.97 (s, 3H), 7.25 (m, 1H), 7.39–7.75
(m, 4H), 8.00 (dd, 1H, J¼7.8, 1.0 Hz), 8.63 (d, 1H,
J¼7.8 Hz) ppm; 13C NMR (CDCl3, 67.5 MHz) d 52.2,
87.8, 93.2, 122.8, 127.4, 128.5, 130.4, 131.7, 132.1, 134.3,
136.0, 143.4, 150.0, 166.2 ppm; IR (film) 2221,
1726 cmꢂ1; HRMS (EI): calcd for C15H11NO2: 237.0790;
found 237.0800.
4.1.8.28. 2-Ethynylbenzoic acid (8g).16h White solid;
mp 121–123 ꢀC; Rf 0.18 Et2O/pentane (30/70)+0.1%
CH3COOH; H NMR (CDCl3, 270 MHz) d 3.46 (s, 1H),
1
7.45 (td, 1H, J¼7.7, 1.4 Hz), 7.54 (td, 1H, J¼7.7, 1.4 Hz),
7.67 (dd, 1H, J¼7.7, 1.4 Hz), 8.10 (dd, 1H, J¼7.7,
1.4 Hz), 11.83 ppm; 13C NMR (CDCl3, 67.5 MHz) d 81.7,
83.3, 123.2, 128.6, 131.2, 132.6, 135.2, 171.3 ppm; IR
(KBr) 3275, 3071, 1693 cmꢂ1; HRMS (EI): calcd for
C9H6O2: 146.0368; found 146.0363.
4.1.8.23. 2-(Pyridin-2-ylethynyl)benzoic acid (8d).
Yellow solid mp >250 ꢀC; Rf 0.74 CH2Cl2/MeOH (90/
10)+0.1% CH3COOH; H NMR (CDCl3, 270 MHz) d 6.91
1
(t, 1H, J¼7.9 Hz), 7.49–7.52 (m, 2H), 7.61–7.63 (m, 2H),
7.79–7.84 (m, 2H), 8.61 (d, 1H, J¼7.9 Hz), 14.71 (s, 1H)
ppm; 13C NMR (CDCl3, 67.5 MHz) d 97.5, 115.2, 120.3,
120.7, 120.8, 132.1, 132.4, 134.1, 139.4, 139.7, 141.1,
151.3, 190.1, 193.9 ppm; IR (KBr) 3024 cmꢂ1; HRMS
(EI): calcd for C14H9NO2: 223.0633; found 233.0624.
4.1.8.29. Methyl 2-(pent-1-ynyl)benzoate (6h).16e Color-
less oil; Rf 0.46 CH2Cl2/pentane (10/90); 1H NMR
(CDCl3, 270 MHz) d 1.07 (t, 3H, J¼7.2 Hz), 1.66 (sext,
2H, J¼7.2 Hz), 2.46 (t, 2H, J¼7.2 Hz), 3.91 (s, 3H), 7.30
(td, 1H, J¼7.6, 1.2 Hz), 7.41 (td, 1H, J¼7.6, 1.2 Hz,), 7.51
(dd, 1H, J¼7.6, 1.2 Hz), 7.88 (dd, 1H, J¼7.6, 1.2 Hz)
ppm; 13C NMR (CDCl3, 67.5 MHz) d 13.5, 21.7, 22.1,
51.9, 79.3, 95.7, 124.4, 127.0, 130.0, 131.3, 131.9, 134.11,
4.1.8.24. Methyl 2-((2-ethyl-6-methylphenyl)ethynyl)-
benzoate (6e). Colorless oil; Rf 0.40 Et2O/pentane (10/90);