An efficient and convenient method for the synthesis of dialkoxymethanes using kaolinite as a catalyst

Article abstract of DOI:10.1081/SCC-120018774

A one pot synthesis of dialkoxymethanes (2a-h) is described from the reaction of alcohols (1a-h) with paraformaldehyde under reflux in the presence of catalytic amount of kaolinite.

Full text of DOI:10.1081/SCC-120018774

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An Efficient and Convenient Method for the Synthesis
of Dialkoxymethanes Using Kaolinite as a Catalyst
a
a
Devendra D. Pathak & J. Joe Gerald
a
Department of Applied Chemistry, Indian School of Mines, Dhanbad, Jharkhand, India
Published online: 16 Aug 2006.
To cite this article: Devendra D. Pathak & J. Joe Gerald (2003): An Efficient and Convenient Method for the Synthesis of
Dialkoxymethanes Using Kaolinite as a Catalyst, Synthetic Communications: An International Journal for Rapid Communication
of Synthetic Organic Chemistry, 33:9, 1557-1561
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Õ
SYNTHETIC COMMUNICATIONS
Vol. 33, No. 9, pp. 1557–1561, 2003
An Efficient and Convenient Method for
the Synthesis of Dialkoxymethanes
Using Kaolinite as a Catalyst
Devendra D. Pathak* and J. Joe Gerald
Department of Applied Chemistry, Indian School of
Mines, Dhanbad, Jharkhand, India
ABSTRACT
A one pot synthesis of dialkoxymethanes (2a–h) is described from the
reaction of alcohols (la–h) with paraformaldehyde under reflux in the
presence of catalytic amount of kaolinite.
Key Words: Kaolinite; Dialkoxymethanes; Catalysis.
*
Correspondence: Devendra D. Pathak, Department of Applied Chemistry,
Indian School of Mines, Dhanbad 826 004, Jharkhand, India; E-mail: ddpathak@
yahoo.com.
1
557
DOI: 10.1081/SCC-120018774
Copyright & 2003 by Marcel Dekker, Inc.
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558
Pathak and Gerald
In organic synthesis introduction or removal of a particular
functional group is of great importance. In such cases selecting a catalyst
to achieve the desired product plays a crucial role. In our present study
[
1,2]
we find that kaolinite, a clay mineral,
acts as an excellent catalyst for
the efficient conversion of alcohols to dialkoxymethanes in high yields, by
the insertion of a methylene group. The kaolin mineral includes kaolinite,
[3]
nacrite, and dickite. Among the three minerals, kaolinite is ubiquitous
in nature and it has proved to be a very good catalyst for a wide variety of
organic transformations, such as conversion of allyl and cinnamyl esters
[
4]
to their corresponding carboxylic acids, regioselective chlorination of
[
arenes and chemoselective protection of aldehydes and ketones.
5]
However, some of the methods suffer from using expensive reagents
and formation of side products. Interestingly, we find that kaolinite is
highly selective towards formation of dialkoxymethanes as it does not
affect otherfunctional g ro ups p re sent in the molecule such as alkyne and
benzyl groups. The catalytic activity of kaolinite, both in their natural
and ion-exchanged forms, may be attributed to its Lewis and Bronsted
[6,7]
acid property.
We herein report the kaolinite catalyzed formation of dialkoxy-
methanes by the reaction of alcohols and paraformaldehyde under
reflux in high yields (Sch. 1). Naturally occurring kaolinite clays, contain-
ing transition metals such as Fe and Ti in their lattice, have been exam-
[
8]
ined for their acidic properties and catalytic activity.
The reaction scheme shows the conversion of alcohols to their
corresponding ether derivatives in the presence of kaolinite at reflux
temperature for 8 to 12 h (See Table 1). All reactions proceed smoothly
to give the desired product in high yields. It is noteworthy that even the
alkyne functional group, in the case of propargyl alcohol, remains
unaffected under the reaction conditions. All products were characterized
1
by H NMR and IR spectroscopic studies. The infrared spectra of
all products (2a–h) exhibit a characteristic ether linkage in the range
Scheme 1.

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Synthesis of Dialkoxymethanes
1559
Table 1. Kaolinite catalyzed syntheses of dialkoxymethanes
2a–h) from alcohols (1a–h) and paraformaldehyde.
(
a
Entry
no.
Reaction
ꢀ
Reaction
Alcohol temp. ( C) time (h) Product
Yield
(%)
1
2
3
4
5
6
7
8
1a
1b
1c
1d
1e
1f
90
95
8
8
2a
2b
2c
2d
2e
2f
70
75
85
80
70
75
78
70
85
9
Refluxed
Refluxed
120
12
10
8
1g
1h
110
Refluxed
8
2g
2h
9
a
Isolated yield.
À1 [9]
1
The H NMR spectra of products confirm the
from 1085–1150 cm
.
absence of hydroxyl proton and shifting of aliphatic resonances towards
downfield. We believe that paraformadehyde enters the interlamellar
space of the kaolinite and decompose to give formaldehyde, which in
turn, reacts with alcohol to yield the desired product. The catalyst used
in this reaction offers several advantages such as ease of separation,
[
10]
recyclability, nontoxicity, and lowcost.
EXPERIMENTAL SECTION
1
The H NMR spectra were recorded in CDC1 solution on a Bruker
00 MHz instrument with tetramethylsilane as internal standard. The IR
3
3
spectra were recorded on a Perkin–Elmer 2000 spectrometer. Alcohols
were purchased from Sigma–Aldrich and used as received. The clay,
kaolinite, was obtained from Anglo-American Clays Corporation,
Sandersville, Georgia, USA.
GENERAL PROCEDURE
A mixture of paraformaldehyde (5 g), alcohol (la–h, 2–4 equiv.) and
kaolin (500 mg) was heated under reflux for about 8–12 h. The reaction
mixture was cooled to room temperature and the catalyst was removed
by filtration. The excess of alcohol was removed by distillation and the

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560
Pathak and Gerald
remaining residue distilled under vacuum to give dialkoxymethane. In the
case of diethoxymethane (2c) the catalyst was removed by filtration and
the filtrate was diluted with equal volume of sodium carbonate solution
(5%). The organic layer was separated, dried over anhydrous sodium
sulphate, and distilled to give diethoxymethane. The catalyst may be
easily regenerated by washing with chloroform followed by drying at
ꢀ
110 C for2 h. The catalyst may be er used without any significant loss
of catalytic activity.
In conclusion, the present procedure describes a general methodol-
ogy for the preparation of dialkoxymethanes from a variety of alcohols
(
la–h). Use of inexpensive, reusable, and eco-friendly catalyst, high yield
of products and operational simplicity make this procedure an attractive
method forthe synthesis of dialkoxymethanes. Fu tr herwo kr is under
progress to utilize kaolinite in several other Lewis acid mediated organic
transformations.
SPECTROSCOPIC DATA
ꢀ
Dipropargyloxymethane (2a): Colorless liquid, b.p. 114–115 C. IR
À1
1
cm ): 3293, 2120, 1375, 1106, 674. H NMR (ꢀ): 2.45 (m, 2H), 4.26
(
(
m, 4H), 4.88 (m, 2H).
Di-n-propyloxymethane (2b): Colorless liquid, b.p. 97–98 C. IR
ꢀ
À1
1
cm ): 2968, 2940, 2882, 1465, 1390, 1114. H NMR (ꢀ): 0.93 (t, 6H),
(
1
.58 (m, 4H), 3.54 (m, 4H), 4.86 (m, 2H).
Diethoxymethane (2c): Colorless liquid, b.p. 85–88 C. IR (cm ):
ꢀ
À1
1
980, 2916, 1440, 1393, 1102. H NMR (ꢀ): 1.22 (t, 6H), 3.39 (q, 4H),
.80 (s, 2H).
2
4
ꢀ
Di-n-butyloxymethane (2d): Colorless liquid, b.p. 149–150 C. IR
À1
1
cm ): 2960, 2935, 2875, 2768, 1466, 1383, 1115, 827, 738. H NMR
(
(
ꢀ): 0.98 (t, 6H), 1.55 (m, 8H), 3.60 (m, 4H), 4.80 (s, 2H).
Di-iso-butyloxymethane (2e): Colorless liquid, b.p. 98–100 C. IR
ꢀ
À1
1
cm ): 2960, 2878, 1471, 1391, 1118. H NMR (ꢀ): 0.92 (d, 12H), 1.54
(
(
m, 2H), 3.35 (d, 4H), 4.84 (s, 2H).
Di-n-octyloxymethane (2f ): Colorless liquid, b.p. 138–140 C. IR
ꢀ
À1
1
(
1
cm ): 2958, 2860, 1468, 1382, 1116, 1080. H NMR (ꢀ): 0.90 (t, 6H),
.27–1.55 (m, 24H), 3.52 (t, 4H), 4.66 (s, 2H).
Dibenzyloxymethane (2g): Colorless liquid, b.p. 120–121 C. IR
ꢀ
À1
1
(
4
cm ): 3089, 3065, 3032, 1497, 1454, 1380, 1136, 739. H NMR (ꢀ):
.60 (s, 4H), 4.80 (s, 2H), 7.28 (s, 10H).

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Synthesis of Dialkoxymethanes
1561
ꢀ
Dicyclohexyloxymethane (2h): Colorless liquid, b.p. 148–150 C. IR
À1
1
cm ): 2793, 1451, 1372, 1143, 1105, 1041, 934, 890. H NMR (ꢀ):
(
1.16–1.93 (m, 20H), 3.53–3.60 (m, 2H), 4.77 (s, 2H).
ACKNOWLEDGMENT
One of the authors J. J. G. would like to thank The Director, ISM,
Dhanbad forthe awa rd of re sea rc h fellowship.
REFERENCES
1
2
. (a) Cornellis, A.; Laszlo, P. Synthesis 1985, 909; (b) Laszlo, P. Acc.
Chem. Res. 1986, 19, 121.
. (a) Kellendonk, F.J.A.; Heinerman, J.J.L.; Van Santen, R.A.;
Mckillop, A.; Clissold, D.W.; Pinnavaia, T.J.; Foucaud; Adams,
J.M. In Preparative Chemistry Using Supported Reagents;
Laszlo, P., Ed.; Academic Press: New York, 1987; Vol. 8,
453–528. For recent reviews; see: (b) Balogh; M.L.P. In Organic
Chemistry Using Clays; Springer-Verlag: New York, 1993; (c)
Murrey, H.H., et al., Eds. Kaolin Genesis and Utilization; The
Clay Mineral Society: Boulder, 1993.
3. Brindley, G.W.; Brown, G. Crystal Structure ofClay Minerals and
their X-ray Identification; Mineralogy Society: London, 1980;
2–39pp.
4
5
. Gajare, A.S.; Shingare, M.S.; Kulkarni, V.R.; Barhate, N.B.;
Wakharkar, R.D. Synth. Commun. 1998, 28, 25–33.
. Ponde, D.E.; Borate, H.B.; Sudalai, A.; Ravidran, T.; Deshpande,
V.H. Tetrahedron Lett. 1996, 37, 4605–4608.
6. Cornellis, A.; Laszlo, P. Syn. Lett. 1994, 155.
7
. (a) Van Bakkum, H.; Kouwenhoren, H.W. Recl. Trav. Chem.
Pays-Bas. 1989, 108, 283; (b) Dauben, W.G.; Cogen, J.M.; Beher, V.
Tetrahedron Lett. 1990, 31, 3241.
8. (a) Laszlo, P. Pure and Appl. Chem. 1990, 62, 2027; (b) Delaude, L.;
Lazla, P.; Smith, K. Acc. Chem. Res. 1993, 26, 607.
9. Silverstein, R.M.; Bassler, G.C.; Morrill, T.C. Spectroscopic
Identification ofOrganic Compounds ; John Wiley & Sons: London,
1
981; 115–116pp.
0. Sabu, K.R.; Sukumar, R.; Lalithambika, M. Bull. Chem. Soc. Jpn.
993, 66, 3535–3541.
1
1
Received in the UK April 17, 2002

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