Silica-alumina catalyzed of 2,4-pentanedione with formaldehyde and α,ω-dithiols

Full text of DOI:10.1134/S1070428014020262

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2014, Vol. 50, No. 2, pp. 293−295. © Pleiades Publishing, Ltd., 2014.
Original English Text © V.R. Akhmetova, N.S. Akhmadiev, V.A. Veklov, B.I. Kutepov, 2014, published in Zhurnal Organicheskoi Khimii, 2014, Vol. 50, No. 2,
pp. 300−302.
SHORT
COMMUNICATIONS
Silica-Alumina Catalyzed of 2,4-Pentanedione
with Formaldehyde and α,ω-Dithiols
V. R. Akhmetova, N. S. Akhmadiev, V. A. Veklov, and B. I. Kutepov
Institute of Petrochemistry and Catalysis, Russian Academy of Sciences,
Ufa, 450075 Russia
е-mail: ink@anrb.ru; vnirara@mail.ru
Received July 1, 2013
DOI: 10.1134/S1070428014020262
Depending on the character of initial reagents the con-
densation of 2,4-pentanedione with aldehydes and thiols
in water environment leads to the formation in 15–98%
yields of β-sulfanyldiketones exhibiting a wide range of
pharmacologic characteristics [1, 2].
Aiming at increasing the yield we carried out the
reaction in the presence of heterogeneous catalysts.
Poly-(4-vinylpyridine)alumina-silica (PVP/Al2O3–SiO2)
at the molar ratio Al2O3–SiO2 0.31–0.83 catalyzed the
Knoevenagel condensation of 1,3-dicarbonyl compounds
with aldehydes [4]. In view of these data we applied to
the reaction alumina-silica catalysts obtained from ethyl
silicate-40 [5] in the presence of surfactant Reapon-4
(see the table, samples nos. 1–4), and samarium silicates
(samples nos. 10, 11), and also catalysts obtained by
annealing and deposition of elements in the pores of
thermohydrated silica gel (samples nos. 5–9, 12).Among
the tested alumina-silica catalysts (samples nos. 1–5) the
sampleAl2O3–SiO2 with the molar ratio 0.0125 : 1 exhib-
We presumed that the condensation of 2,4-pentane-
dione (I) with formaldehyde and α,ω-dithiols would
allow the synthesis of cyclic III [3] or linearly bound
β,β′-disulfanyldiketones IV (see the scheme). Preliminary
experiments showed that the reaction without catalyst
of diketone I with formaldehyde and 1,2-ethanedithiol
(IIb) (Н2О, 80–100°С, 8 h [1]) afforded 3,10-diacetyl-
5,8-dithiadodecane-2,11-dione (IVb) in a yield ≤20%
(conversion ~30%).
O
O
S
S
_
X
Al O SiO
O
O
2
3
2
+
+
CH2O
IIIa, IIIb
R SH
IIa_IId
I
O
O
O
O
X
S
S
IVa_IVd
II, R = H (a), C2H4SH (b), (CH2)2O(CH2)2O(CH2)2SH (c), p-C6H4OC6H4SH-p (d); III, IV, X = (CH2)n, n = 1 (a), 2 (b);
(CH2)2O(CH2)2O(CH2)2 (c), p-C6H4OC6H4-p (d).
293

AKHMETOVA et al.
294
Yield of compounds IVc and IVd depending on the used catalyst
Yield, %
Catalyst composition
Surfactant consumption per
weight unit of catalyst, %
Sample no.
(molar ratio)
IVc
36
21
86
81
71
63
67
74
49
72
78
63
IVd
27
15
91
87
68
79
42
39
33
65
74
79
1
2
Al2O3–SiO2 (0.050 : 1)
Al2O3–SiO2 (0.025 : 1)
1.5
1.5
1.5
3.0
–
3
Al2O3–SiO2 (0.0125 : 1)
4
Al2O3–SiO2 (0.0125 : 1)
5
Al2O3–SiO2 (0.0429 : 1)
6
11.7 wt % FeCl3·6H2O/Al2O3–SiO2 (0.0125 : 1)
8.9 wt % MnCl2·4H2O/Al2O3–SiO2 (0.0125 : 1)
4.1 wt % MnO2/Al2O3–SiO2 (0.0125 : 1)
4.1 wt % CoO/Al2O3–SiO2 (0.0125 : 1)
Sm2O3–SiO2 (0.0125 : 1)
–
7
–
8
–
9
–
10
11
12
1.5
3.0
–
Sm2O3–SiO2 (0.0125 : 1)
Sm2O3–SiO2 (0.0429 : 1)
ited the highest activity (sample no. 3). In the presence of
this catalyst (5 mol %) the reaction (Н2О, 80–100°С, 8 h)
afforded compound IVb in 43% yield. When the reac-
tion was carried out in a mixture Н2О–С2Н5ОН–СНСl3
the yield of compound IVb grew to 60%. Under the
developed conditions the three-component condensation
of diketone I, formaldehyde and H2S in the presence of
the catalyst Al2O3–SiO2,0.0125 : 1, gave thiomethylated
diketone IVа in 47% yield. No formation of cyclic com-
pounds IIIa, IIIb was observed in any runs.
Obviously the reactivity of the heterochain α,ω-di-
thiols in the alumina-silica catalyzed reaction of acetyl-
acetone with formaldehyde is higher than the reactivity
of aliphatic dithiols.
3,9-Diacetyl-5,7-dithiaundecene-2,10-dione (IVа).
2.21 mL (30 mmol) of 37% water solution of form-
aldehyde was at room temperature (~20°С) saturated
with hydrogen sulfide (obtained from the calculated
amount of Na2S and HCl) in the course of 30 min. Then
to the reaction mixture 2.5 mL of СHCl3 and 2.5 mL of
C2H5OH, 1.95 mL(20 mmol) of acetylacetone, and 0.11 g
(1.63 mmol) of Al2O3–SiO2 was added. The mixture
was stirred at ~20°С for 6 h. The reaction mixture was
filtered through a silica gel bed, the reaction products
were extracted with ethyl acetate (3 × 15 mL), the extract
was dried with Na2SO4, evaporated on a rotary evapora-
tor, and the reaction products were separated by column
chromatography on silica gel (eluent hexane–chloro-
form–ethyl acetate, 1 : 1 : 4). Yield 47%, oily substance,
nD20 1.5124. IR spectrum, cm–1: 1726 (С=О), 1420 (CH2),
In extension of the synthesis to compounds where the
2,4-dioxopentane-3-yl fragments are bound with chains
containing oxygen and sulfur atoms we studied the reaction
of diketone I with formaldehyde and heterochain α,ω-di-
thiols. In reactions of acetylacetone with formaldehyde,
3,6-dioxaoctane-1,8-dithiol (IIc) or 4-(4-sulfanylphenoxy)
thiophenol (IId) a high catalytic activity was exhibited by
alumina-silica Al2O3–SiO2, 0.0125 : 1 (sample no. 3) and
0.0429 : 1 (sample no. 4), and also catalysts based on de-
posited on alumina-silica FeCl3 (sample no. 6) and Sm2O3
(samples nos. 10–12). With these catalysts the yields of
3,16-diacetyl-8,11-dioxa-5,14-dithiaoctadecane-2,17-
dione (IVc) and 3-{4-[4-(2-acetyl-3-oxobutylsulfanyl)-
phenoxy]phenylsulfanylmethyl}pentane-2,4-dione (IVd)
reached 63–90%.
1
1074 (С–О), 720 (С–S). Н NMR spectrum, δ, ppm:
2.12 s (12Н, H3С14,17,18,19), 2.82 m (4Н, H2С4,8), 3.65 t
(2Н, HС5,9, Ј 7.1 Hz), 4.32 br.s (2Н, H2С2). 13С NMR
spectrum, δ, ppm: 24.31 (C14,17,18,19), 29.61 (C4,8), 33.27
(C2), 69.15 (С5,9), 192.73 (С6,10,12,15). Mass spectrum: m/z
327.241 [M + Na]+. Found, %: С 50.82; Н 6.44; S 20.91.
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SILICA-ALUMINA CATALYZED REACTION
295
С13Н20O4S2. Calculated, %: С 51.29; Н 6.62; S 21.07.
M 304.427.
1697 and 1581 (С=О), 1485 и 1555 (Ar), 1416 (CH2),
1238 (Ar–O–Ar), 1012 (С–О), 714 (С–S). Н NMR
1
spectrum, δ, ppm: 2.16 s (12Н, H3С21,27,30,31), 3.76 s (4Н,
H2С8,23), 3.85 t (2Н, НС9,24, J 6.8 Hz), 6.92–7.50 m (8Н,
HСAr). 13С NMR spectrum, δ, ppm: 22.67 (С21,27,30,31),
34.58 (C8,23), 69.15 (C9,24), 119.58–156.64 (CAr), 192.44
(С10,19,25,28). Mass spectrum: m/z 481.196 [M + Na]+.
Found, %: С 61.60; Н 5.56; S 14.24. С24Н26O5S2.Calcu-
lated, %: С 62.86; Н 5.71; S 13.98. M 458.592.
Catalytic thiomethylation of acetylacetone with
formaldehyde and α,ω-dithiols. Into a Schlenk vessel
under argon atmosphere at room temperature (~20°С)
was charged 1.47 mL (20 mmol) of 37% water solu-
tion of formaldehyde, 10 mmol of an appropriate α,ω-
dithiol, and the mixture was stirred for 30 min. Then
to the mixture was added 2.5 mL of СHCl3 and 2.5 mL
of C2H5OH, 1.95 mL (20 mmol) of acetylacetone, and
1 mmol of alumina-silica catalyst, the reaction mixture
was stirred at ~20°С for 6 h. The reaction mixture was
filtered through a bed of silica gel, the filtrate was dried
with Na2SO4. The reaction products were separated by
column chromatography on silica gel (eluent hexane–
chloroform–ethyl acetate, 1 : 1 : 4).
NMR spectra were registered on a spectrometer Bruk-
er Avance-400 in CDCl3, operating frequencies 400.13
(1Н) and 100.62 (13С) MHz. Mass spectra were obtained
on an instrument MALDI-TOF Autoflex III, matrices
α-cyano-4-hydroxycinnamic and 2,5-dihydrobenzoic
acids. IR spectra were recorded on a spectrophotometer
Bruker Vertex 70V from mulls in mineral oil. Elemental
analysis was performed on an analyzer Carlo Erba 1106.
Column chromatography was carried out on silica gel
(50–160 μm), TLC analysis was done with the use of
Silufol UV-254 plates, development in iodine vapor.
3,10-Diacetyl-5,8-dithiadodecane-2,11-dione (IVb).
Yield 59%, white crystals, mp 138–140°С. IR spectrum ν,
cm–1: 3434 (O–H), 1691 (С=О), 1418 (CH2), 1020 (С–О),
1
724 (С–S). Н NMR spectrum, δ, ppm: 2.27 s (12Н,
H3С15,18,19,20), 2.80 s (4Н, H2С6,7), 3.51 br.s (4Н, H2С2,9),
16.74 s (2Н, ОН). 13С NMR spectrum, δ, ppm: 22.68
(C15,18,19,20), 30.35 (C9,5), 32.33 (C2,3), 106.21 (С6,10),
191.82 (С7,11,13,16). Mass spectrum: m/z 341.255 [M +
Na]+. Found, %: С 51.86; Н 6.80; S 20.60. С14Н22O4S2.
Calculated, %: С 52.80; Н 6.96; S 20.14. M 318.454.
ACKNOWLEDGMENTS
The study was carried out under a financial support
of the Russian Foundation for Basic Research (grants
nos. 11-03-00101-а, 11-03-97011-р_Povolzh’e, 13-03-
12027 ofi_m).
3,16-Diacetyl-8,11-dioxa-5,14-dithiaoctadecane-
2,17-dione (IVc). Yield 86%, oily substance, nD20 1.5348.
IR spectrum ν, cm–1: 1699 (С=О), 1599, 1418 (CH2), 1110
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RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 50 No. 2 2014