Unexpected formation of 1,6-bis[3,5-dimethyl-4-(1,4,6-oxadithiocan-5-yl)- 1H-pyrazol-1-yl]hexane in the reaction of 1,1′-(hexane-1,6-diyl)bis[3,5- dimethyl-1H-pyrazole-4-carbaldehyde] with 2-sulfanylethanol

Full text of DOI:10.1134/S1070428008100291

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2008, Vol. 44, No. 10, pp. 1554–1555. © Pleiades Publishing, Ltd., 2008.
Original Russian Text © L.K. Papernaya, E.V. Rudyakova, A.I. Albanov, G.G. Levkovskaya, 2008, published in Zhurnal Organicheskoi Khimii, 2008,
Vol. 44, No. 10, pp. 1575–1576.
SHORT
COMMUNICATIONS
Dedicated to Full Member of the Russian Academy of Sciences
B.A. Trofimov on his 70th anniversary
Unexpected Formation of 1,6-Bis[3,5-dimethyl-4-(1,4,6-oxa-
dithiocan-5-yl)-1H-pyrazol-1-yl]hexane in the Reaction
of 1,1′-(Hexane-1,6-diyl)bis[3,5-dimethyl-1H-pyrazole-
4
-carbaldehyde] with 2-Sulfanylethanol
L. K. Papernaya, E. V. Rudyakova, A. I. Albanov, and G. G. Levkovskaya
Favorskii Irkutsk Institute of Chemistry, Siberian Division, Russian Academy of Sciences,
ul. Favorskogo 1, Irkutsk, 664033 Russia
e-mail: papern@irioch. irk.ru
Received June 2, 2008
DOI: 10.1134/S1070428008100291
We previously reported that reactions of aldehydes
of the thiophene series [1–3] with alkanethiols and
dithiols in the presence of chloro(trimethyl)silane
ously unknown 1,6-bis[3,5-dimethyl-4-(1,4,6-oxadi-
thiocan-5-yl)-1H-pyrazol-1-yl]hexane (II) with high
selectivity. It should be noted that the expected pyra-
zolyl-substituted oxathiolane was not formed in excess
Me SiCl at a I-to-HSCH CH OH ratio of 1:2; in this
case, we isolated a mixture of unreacted initial pyra-
zolecarbaldehyde I and compound II. No reaction
occurred at room temperature.
Me SiCl at reduced temperature provide a simple and
3
convenient synthetic route to acyclic and cyclic dithio-
acetals possessing thiophene fragments. It is also
known that 2-sulfanylethanol and 3-sulfanylpropan-1-
ol react with aliphatic and aromatic aldehydes in the
presence of scandium trifluoromethanesulfonate [4],
boron trifluoride [5], or p-toluenesulfonic acid [6] to
give the corresponding 1,3-oxathiolane and 1,3-oxa-
thiane derivatives.
3
2
2
The structure of compound II was determined on
1
13
the basis of its H and C NMR spectra and elemental
analysis. The described reaction leading to 1,4,6-oxa-
dithiocane derivative II is the first example of syn-
thesis of formylpyrazole precursors. Compound II
attracts strong interest as a promising biologically
active substance, for molecules of many modern drugs,
specifically antiphlogistic, antidiabetic, analgesic, etc.
In the present work we tried to extend the above
approach [1–3] with a view to obtain pyrazoles having
an O,S-heterocyclic substituent by reaction of formyl-
pyrazoles with 2-sulfanylethanol in chloro(trimethyl)-
silane. However, contrary to the expectations, 1,1′-(hex-
ane-1,6-diyl)bis[3,5-dimethyl-1H-pyrazole-4-carbalde-
hyde] reacted with 2-sulfanylethanol at 50–70°C in 10-
fold amount of chloro(trimethyl)silane to give previ-
[
7], as well as of insectoacaricides [8], contain a pyra-
zole ring.
1,6-Bis[3,5-dimethyl-4-(1,4,6-oxadithiocan-5-yl)-
1H-pyrazol-1-yl]hexane (II). 2-Sulfanylethanol,
Me
N
O
N
Me
CHO
Me
4HSCH CH OH
N
S
Me
2
2
Me
N
Me SiCl
3
S
2
'
5
4
S
N
Me
3'
OCH
N
S
N
3
Me
1
'
O
N
Me
I
II
1
554

UNEXPECTED FORMATION OF 1,6-BIS[3,5-DIMETHYL-4-(1,4,6-OXADITHIOCAN-5-YL)-...
.66 g (2 mmol), was added dropwise to a hot solution REFERENCES
1555
0
of compound I in 2.5 ml of Me SiCl, and the mixture
3
1
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2
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2
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1
1
1
2
6
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2
3
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2
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2
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3
3
1
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1
3
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3
′
2′
3
5
6
. Wilson, G.E., Hvang, J., and Schloman, W.W., J. Org.
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3
6.24 (SCH ), 43.73 (SCHS), 49.78 (NCH ), 62.88
2
2
4
3
5
(
OCH ), 119.99 (C ), 145.08 and 144.97 (C , C ).
2
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C H O N S . Calculated, %: C 54.92; H 7.04;
2
6
42
2
4
4
N 9.85; S 22.69.
7
. Elguero, J., Goya, P., Jagerovic, N., and Silva, A.M.S.,
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1
13
The H and C NMR spectra were recorded on
a DPX-400 spectrometer at 400.13 and 101.61 MHz,
respectively, using CD OD as solvent and hexamethyl-
3
disiloxane as internal reference.
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RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 44 No. 10 2008