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1
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).