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B. C. Ranu and T. Mandal
Table 3. IR, and 1H and 13C NMR data and elemental analysis of products
Entries 2, 5, 6, 14, 15, 20, 22, 26 in Table 1 and entry 4 in Table 2
Entry
2
νmax [cm−1
]
δH [ppm]
δC [ppm]
Analysis [%]
1452, 1478, 1724, 2727
1.17 (t, 3H, J 7.41), 2.30–2.39 (m, 2H),
2.95 (d, 2H, J 7.50), 4.37 (t, 1H, J 7.50),
7.25–7.38 (m, 5H), 9.6 (t, 1H, J 1.68)
14.6, 25.5, 43.2, 50.1, 127.9,
128.0 (2C), 129.1 (2C),
141.7, 199.9
Found: C 67.9, H 7.1
C11H14OS requires C 68.0, H 7.3
5
6
1454, 1479, 1708
2.07 (s, 3H), 3.04 (d, 2H, J 7.2), 4.67
(t, 1H, J 7.2), 7.18–7.26 (m, 9H)
31.1, 48.6, 49.6, 127.9,
128.1 (2C), 128.9 (2C),
129.3 (2C), 132.9, 134.2,
134.7 (2C), 141.2, 205.6
Found: C 66.0, H 5.1
C
16H15ClOS requires C 66.1, H 5.1
1039, 1441, 1478, 1715
20.7 (s, 3H), 2.91–2.99 (m, 2H),
4.65 (t, 1H, J 7.52), 5.91 (s, 2H),
6.67–6.71 (m, 2H), 6.82–6.83 (m, 1H),
7.21–7.34 (m, 5H)
31.1, 48.3, 50.1, 101.4,
108.2, 108.3, 121.5, 127.9,
129.2 (2C), 133.0 (2C),
134.4, 135.2, 147.2,
148.1, 205.9
Found: C 67.8, H 5.3
17H16OS requires C 68.0, H 5.4
C
14
15
20
22
1434, 1479, 1546
4.68–4.88 (m, 3H), 7.18–7.21 (m, 2H),
7.27–7.40 (m, 8H)
49.6, 78.7, 129.3 (2C), 129.4
(2C), 129.6 (2C), 129.8
(2C), 134.3 (2C), 134.9,
135.3
Found: C 64.7, H 4.9
C14H13NO2S requires C 64.8, H 5.1
1039, 1444, 1479, 1504,
1556
1.22 (t, 3H, J 7.47), 2.46 (q, 2H, J 7.47),
4.50 (t, 1H, J 7.80), 4.66–4.71 (m, 2H),
5.96 (s, 2H), 6.75–6.79 (m, 2H),
6.85–6.87 (m, 1H)
14.7, 26.0, 46.6, 79.8, 101.7,
108.0, 108.8, 121.7, 131.4,
148.1, 148.6
Found: C 51.6, H 5.0
C11H13NO2S requires C 51.8, H 5.1
1448, 1477
1.18 (t, 3H, J 7.41), 2.29 (m, 2H), 3.50
(d, 2H, J 7.05), 4.57 (t, 1H, J 7.05),
7.26–7.28 (m, 2H), 7.35–7.57 (m, 5H),
7.89–7.92 (m, 2H)
14.7, 25.8, 43.6, 45.6, 128.4
(2C), 129.0 (2C), 129.1
(2C), 129.6 (2C), 133.7,
137.0, 141.2, 143.7, 197.0
Found: C 66.5, H 5.5
C
17H17ClOS requires C 67.0, H 5.6
1170, 1452, 1478, 1598,
1678
0.83 (t, 3H, J 7.29), 1.24–1.34 (m, 2H),
1.43–1.51 (m, 2H), 2.25–2.38 (m, 2H),
3.47 (d, 2H, J 7.05), 4.52–4.64 (m, 3H),
5.29–5.44 (m, 2H), 5.99–6.05 (m, 1H),
6.92 (d, 2H, J 8.79), 7.20–7.32 (m, 3H),
7.40–7.43 (m, 2H), 7.89 (d, 2H, J 8.79)
13.9, 22.3, 31.5, 31.6, 44.8,
45.4, 69.3, 114.8, 118.6,
127.5 (2C), 128.2 (2C),
128.8 (2C), 130.7 (2C),
132.8, 142.8, 144.4,
162.9, 195.8
Found: C 74.5, H 7.3
22H26O2S requires C 74.5, H 7.4
C
26
4
1445, 1475, 1589, 1679
1448, 1479, 1579, 1681
3.57–3.78 (m, 2H), 5.29 (dd, 1H, 1J 7.53,
2J 6.39), 6.84–6.88 (m, 2H), 7.27–7.30
(m, 3H), 7.39–7.59 (m, 6H), 7.92–7.95
(m, 2H)
44.1, 46.1, 124.9, 125.9,
126.9, 128.7, 128.8 (2C),
129.1 (2C), 129.3 (2C),
133.4 (2C), 133.8, 134.2,
136.9, 145.8, 196.9
Found: C 70.3, H 4.9
C19H16OS2 requires C 70.3, H 5.0
3.46 (d, 2H, J 6.81), 5.07 (t, 1H, J 6.81),
7.26 (d, 2H, J 8.49), 7.34–7.60 (m, 9H),
7.85 (d, 2H, J 8.49)
43.9, 53.3, 128.0 (2C),
128.5, 128.6, 129.1 (4C),
129.8 (2C), 131.6, 133.7,
134.4 (4C), 136.2, 136.9,
195.6
Found: C 72.2, H 4.6
C
21H16Cl2OS2 requires C 72.4, H 4.6
followed by purification by column chromatography over
silica gel.
this procedure. The reactions were complete within 2.5–4.5 h.
The yields of isolated products are also very good (70–90%).
The products were characterized by their spectroscopic data and
elemental analysis.
Both aliphatic and aromatic thiols such as ethane thiol,
butane thiol, and thiophenol react with a wide variety of con-
jugated alkenes by this procedure to provide the corresponding
thio-adducts in high yields. The results are summarized in
Table 1. As evident from the results, open-chain α,β-unsaturated
aldehydes, ketones, carboxylic esters, nitriles, and nitro alka-
nes participated in the reaction with thiophenol, butane thiol,
and ethane thiol without any difficulty. The addition of thi-
ols to cyclohexenone also produced high yields. The conjugate
addition of thiols to chalcones which is not always satisfac-
tory with conventional reagents[10b] was also efficiently cat-
alyzed by sodium acetate under the present reaction conditions.
A variety of substituents on the aromatic ring such as OMe,
NO2, ethylenedioxy, and a thiophene moiety are compatible with
The α,β-unsaturated terminal acetylenic ketones underwent
bis-additions with two equivalents of thiol or with one equivalent
of dithiol to provide the corresponding β-keto thioacetals, dithi-
anes, and dithiolanes. The results are reported in Table 2.
The dithianes are very useful intermediates[11] and β-keto
1,3-dithianes, in particular, have been used as key synthons in
the total synthesis of several natural products.[12] The procedures
for synthesis of β-keto dithianes are very limited and the first one
by Michael addition was reported using Al2O3 in 1992.[13]
In general, the reactions are very clean and reasonably fast.
The workup is very simple and short column chromatography is
enough to provide the pure product. Commercial sodium acetate