layer was washed with water (2 × 5 cm3), dried (anh. Na2SO4),
and the solvent was distilled off. A brown gum was obtained
which was purified by column chromatography on silica gel
with the eluent being 1:1 CHCl3–light petroleum to furnish
compound 4a as a white solid, mp 79 ЊC (Found: C, 72.23; H,
5.03. C17H14O2S requires C, 72.31; H, 4.99%); νmax (KBr)/cmϪ1
1710.7, 1589.2, 1562.2; δH (300 MHz; CDCl3) 3.79 (s, 2H,
SCH2), 3.81 (s, 3H, COOCH3), 7.08–7.17 (m, 4H, ArH), 7.25–
7.28 (m, 2H, ArH), 7.37–7.47 (m, 2H, ArH), 7.9 (d, J 7.8 Hz,
1H, ArH); δC (CDCl3) 22.1, 42.5, 83.9, 85.1, 119.6, 123.3, 124.8,
126.4, 128.4, 128.6, 131.7, 132.1, 132.9, 141.1, 167.2; δC (CDCl3;
DEPT 135) 21.8 (inverted), 52.3, 124.5, 126.2, 128.1, 128.3,
131.4, 131.8, 132.6.
Hz, 1H, ArH), 7.58–7.65 (m, 3H, ArH), 7.76 (s, 1H, ArH), 7.88
(dd, J 7.8 and 1.5 Hz, 1H, ArH); δC (CDCl3) 22.2, 52.6, 84.3,
85.4, 120.6, 124.8, 126.4, 126.9, 127.0, 127.9, 128.1, 128.3,
128.8, 131.8, 132.0, 133.0, 133.2, 133.3, 141.1, 167.2; δC (CDCl3;
DEPT 135) 21.9, 52.3, 124.6, 126.2, 126.6, 126.8, 127.8, 128.0,
128.6, 131.5, 131.7, 132.7.
1-(3-Chlorophenyl)-3-[2-(methoxycarbonyl)phenylthio]propyne
4g. White solid, mp 80 ЊC (Found: C, 64.39; H, 4.09. C17H13-
ClO2S requires C, 64.44; H, 4.13%); νmax (KBr)/cmϪ1 1710.7,
1591.2, 1562.2; δH (300 MHz; CDCl3) 3.88 (s, 2H, SCH2), 3.91
(s, 3H, COOCH3), 7.15–7.27 (m, 4H, ArH), 7.33 (s, 1H, ArH),
7.51 (d, J 7 Hz, 2H, ArH), 8.00 (d, J 7.5 Hz, 1H, ArH);
δC (CDCl3) 21.9, 52.6, 82.5, 86.4, 124.9, 126.4, 127.9, 128.9,
129.9, 130.2, 131.8, 131.9, 133.0, 134.4, 140.8, 167.2; δC (CDCl3;
DEPT 135) 21.7, 52.3, 124.6, 126.1, 128.6, 129.6, 130.0, 131.5,
131.7, 132.7.
Compounds 4b–4h were synthesised from aryl iodides 3b–
3h according to the procedure followed for the synthesis of
compound 4a.
3-[2-(Methoxycarbonyl)phenylthio]-1-(p-tolyl)propyne
4b.
White solid, mp 92 ЊC (Found: C, 73.02; H, 5.26. C18H16O2S
requires C, 72.94; H, 5.44%); νmax(KBr)/cmϪ1 1705.0, 1585.4,
1566.1, 1508.2; δH (300 MHz; CDCl3) 2.30 (s, 3H, ArCH3), 3.88
(s, 2H, SCH2), 3.90 (s, 3H, COOCH3), 7.05 (d, J 8.1 Hz, 2H,
ArH), 7.18 (t, J 7.5 Hz, 1H, ArH), 7.24 (d, J 7.8 Hz, 2H, ArH),
7.48 (td, J 7.2 and 1.2 Hz, 1H, ArH), 7.54 (d, J 6.9 Hz, 1H,
ArH), 7.99 (dd, J 7.5 and 1.2 Hz, 1H, ArH); δC (CDCl3) 21.8,
22.2, 52.6, 84.0, 84.2, 120.2, 124.8, 126.5, 128.0, 129.4, 131.7,
132.0, 132.9, 137.7, 138.7, 167.2; δC (CDCl3; DEPT 135) 21.5,
21.9 (inverted), 52.3, 124.5, 126.2, 129.1, 131.4, 131.7, 132.6,
137.3.
3-[2-(Methoxycarbonyl)phenylthio]-1-(2-thienyl)propyne 4h.
White solid, mp 86 ЊC (Found: C, 70.19; H, 4.73. C15H12O2S
requires C, 70.28; H, 4.72%); νmax (KBr)/cmϪ1 1706.9, 1585.4,
1564.2; δH (300 MHz; CDCl3) 3.93 (s, 3H, COOCH3), 3.96 (s,
2H, SCH2), 7.23 (td, J 7.8 and 1.2 Hz, 1H, ArH), 7.41 (dd, J 8.4
and 1.5 Hz, 1H, ArH), 7.45–7.48 (m, 2H, ArH), 7.54 (td, J 8.1
and 1.5 Hz, 1H, ArH), 7.61 (d, J 7.8 Hz, 1H, ArH), 8.03 (dd,
J 7.8 and 1.2 Hz, 1H, ArH); δC (CDCl3) 22.2, 52.6, 84.2, 85.4,
120.5, 124.8, 126.4, 127.1, 127.9, 128.1, 128.8, 131.8, 133.0,
141.1, 167.3; δC (CDCl3; DEPT 135) 21.9 (inverted), 52.3, 124.5,
126.1, 126.6, 127.8, 128.6, 131.5, 132.7.
3-[2-(Methoxycarbonyl)phenylthio]-1-(2-methoxyphenyl)-
propyne 4c. White solid, mp 99 ЊC (Found: C, 69.14; H,
5.09. C18H16O3S requires C, 69.2; H, 5.16%); δH (300 MHz;
CDCl3) 3.83 (s, 3H, ArOCH3), 3.95 (s, 2H, SCH2), 3.98 (s, 3H,
ArH), 6.83 (d, J 8.1 Hz, 2H, ArH), 7.2–7.41 (m, 3H, ArH),
7.75 (d, J 7.5 Hz, 2H, ArH), 8.06 (dd, J 7.5 and 1.2 Hz, 1H,
ArH).
Typical procedure for the synthesis of (E )-2-styryl-3,1-
benzoxathiin-4-one 5a
3-[2-(Methoxycarbonyl)phenylthio]-1-phenylpropyne 4a (1.4
mmol) was stirred with a methanolic solution of potassium
hydroxide (5 M; 25 cm3) at room temperature for 2 h in an
argon atmosphere. After the removal of methanol under
reduced pressure, the residue was diluted with water (5 cm3),
acidified with dil. HCl (1:1) and extracted with diethyl ether
(3 × 30 cm3). The combined organic layer was washed with
water (5 cm3) and dried (anh. Na2SO4). The crude product
obtained was then heated under reflux with CuI (0.28 mmol;
20 mol%) and Et3N (2.86 mmol) in THF (20 cm3) in an argon
atmosphere for 24 h. After removal of the solvent and Et3N, the
residue was purified by column chromatography on silica gel
(60–120 mesh) with the eluent being 1:1 CHCl3–light petroleum
to furnish 5a as a light yellow solid, mp 96 ЊC (Found: C, 71.59;
H, 4.54. C16H12O2S requires C, 71.61; H, 4.50%); νmax (KBr)/
cmϪ1 1726.2, 1593.1, 1541.0; δH (300 MHz; CDCl3) 6.14 (d, J 6
3-[2-(Methoxycarbonyl)phenylthio]-1-(4-methoxyphenyl)-
propyne 4d. White solid, mp 65 ЊC (Found: C, 69.04; H, 5.06.
C18H16O3S requires C, 69.2; H, 5.16%); νmax (KBr)/cmϪ1 1705.0,
1604.7, 1585.4, 1564.2; δH (300 MHz; CDCl3) 3.77 (s, 3H,
ArOCH3), 3.88 (s, 2H, SCH2), 3.91 (s, 3H, COOCH3), 6.78
(d, J 8.76 Hz, 2H, ArH), 7.2 (td, J 7.2 and 1.2 Hz, 1H, ArH),
7.29 (d, J 8.7 Hz, 2H, ArH), 7.47–7.57 (m, 2H, ArH), 7.99
(dd, J 7.7 and 1.2 Hz, 1H, ArH); δC (CDCl3) 21.8, 52.2,
55.2, 83.0, 83.4, 113.8, 115.0, 124.3, 126.1, 129.6, 131.3, 132.5,
131.3, 132.5, 133.1, 140.7, 159.5, 166.8; δC (CDCl3; DEPT 135)
21.9 (inverted), 52.3, 55.4, 114.0, 124.5, 126.2, 131.4, 132.6,
133.2.
Hz, 1H, SCH), 6.32 (dd, J 15.6 and 6 Hz, 1H, CH᎐CHPh), 6.87
᎐
(d, J 15.6 Hz, 1H, CH᎐CHPh), 7.22–7.27 (m, 5H, ArH), 7.34
᎐
(d, J 7.2 Hz, 2H, ArH), 7.41 (t, J 7.2 Hz, 1H, ArH), 8.12 (d,
J 7.8 Hz, 1H, ArH); δC (CDCl3) 82.4, 122.0, 124.7, 127.2, 127.4,
128.0, 129.2, 129.4, 133.1, 134.2, 135.4, 135.81, 138.6, 164.2;
δC (CDCl3; DEPT 135) 82.1, 121.7, 126.9, 127.2, 127.7, 128.9,
129.1, 132.8, 133.9, 135.5.
Compounds 5b–5h were synthesised from 4b–4h following
the procedure for the synthesis of 5a.
3-[2-(Methoxycarbonyl)phenylthio]-1-(1-naphthyl)propyne 4e.
White solid, mp 85 ЊC (Found: C, 75.81; H, 4.83. C21H16O2S
requires C, 75.87; H, 4.85%); νmax (KBr)/cmϪ1 1714.6, 1585.4,
1560.0; δH (300 MHz; CDCl3) 3.73 (s, 3H, COOCH3), 3.73 (s,
2H, SCH2), 7.02 (t, J 7.5 Hz, 1H, ArH), 7.18 (t, J 7.5 Hz, 1H,
ArH), 7.27–7.35 (m, 3H, ArH), 7.42–7.48 (m, 2H, ArH), 7.57–
7.62 (m, 2H, ArH), 7.85 (d, J 7.8 Hz, 1H, ArH), 7.98–8.01 (m,
1H, ArH); δC (CDCl3) 22.3, 25.6, 82.0, 90.1, 120.9, 124.9, 125.6,
126.6, 126.8, 127.1, 128.0, 128.7, 129.2, 130.9, 131.8, 133.0,
133.5, 133.8, 141.0, 167.2; δC (CDCl3; DEPT 135) 22.3, 52.65,
124.9, 125.6, 126.6, 126.8, 127.1, 128.6, 129.2, 130.9, 131.8,
133.0.
(E )-2-[2-(p-Tolyl)vinyl]-3,1-benzoxathiin-4-one 5b. Light
yellow solid, mp 89 ЊC (Found: C, 72.35; H, 5.01. C17H14O2S
requires C, 72.31; H, 4.99%); νmax (KBr)/cmϪ1 1728.1, 1589.2,
1512.2; δH (300 MHz; CDCl3) 2.35 (s, 3H, ArCH3), 6.22 (d,
J 6.3 Hz, 1H, SCH), 6.36 (dd, J 15.9 and 6.3 Hz, 1H,
3-[2-(Methoxycarbonyl)phenylthio]-1-(2-naphthyl)propyne 4f.
White solid, mp 90 ЊC (Found: C, 76.01; H, 4.92. C21H16O2S
requires C, 75.87; H, 4.85%); νmax (KBr)/cmϪ1 1708.8, 1591.2,
1564.2; δH (300 MHz; CDCl3) 3.79 (s, 3H, COOCH3), 3.81 (s,
2H, SCH2), 7.08 (td, J 7.2 and 1.2 Hz, 1H, ArH), 7.27–7.34 (m,
3H, ArH), 7.38 (td, J 8.4 and 1.5 Hz, 1H, ArH), 7.46 (d, J 8.1
CH᎐CHAr), 6.92 (d, J 15.9 Hz, 1H, CH᎐CHAr), 7.16 (d, J 7.8
᎐ ᎐
Hz, 2H, ArH), 7.31–7.37 (m, 4H, ArH), 7.5 (td, J 9 and 1.2 Hz,
1H, ArH), 8.2 (d, J 8.1 Hz, 1H, ArH); δC (CDCl3) 20.3, 81.2,
119.5, 124.8, 125.7, 125.9, 126.5, 128.4, 129.0, 131.6, 132.6,
134.4, 137.3, 138.0, 162.8; δC (CDCl3; DEPT 135) 20.3, 81.2,
119.5, 125.7, 125.9, 126.5, 128.4, 131.6, 132.6, 134.3.
1652
J. Chem. Soc., Perkin Trans. 1, 2001, 1649–1655