Organic Syntheses, Coll. Vol. 5, p.365 (1973); Vol. 47, p.51 (1967).
In a 2-l. three-necked flask
equipped with a stirrer
, a reflux condenser
, and a dropping funnel (Note 1) 832 g. (4.0 moles) of phosphorus pentachloride
is stirred with 250 ml. of phosphorus oxychloride (Note 2)
. To this is added with stirring 264 g. (272 ml., 4.4 moles) of methyl formate (Note 3)
. During the addition the reaction vessel is cooled in an ice bath
to maintain a reaction temperature of 10–20°. The addition requires about 1.75 hours. When the addition is complete, the solution is stirred at a temperature under 30° until all the phosphorus pentachloride
has dissolved (about 1 hour). Then the stirrer is removed, the reflux condenser is replaced by a distilling head, and the reaction mixture is distilled under a pressure of 80–120 mm. with a bath temperature of 50–65° (Note 4)
. During the distillation the receiver is cooled to −10° to −20° by an ice-salt bath
The material which is collected is redistilled through a 90-cm. vacuum-jacketed column packed with glass beads (5 mm.)
using a 1:10 reflux ratio. The fraction, b.p. 80–100°
, is redistilled through the same column to give 353–386 g.
) of dichloromethyl methyl ether
, b.p. 82–85.5°
1.4303 (Note 5)
The reflux condenser and dropping funnel must be provided with calcium chloride tubes
If it is not first distilled under reduced pressure, extensive decomposition will occur during fractional distillation.
The product must be protected from moisture when stored.
4. Merits of the Preparation
Dichloromethyl methyl ether
may be employed preparatively in various ways. Thus it effects the replacement of carbonyl and hydroxyl oxygens by chlorine,11
and may be used in the preparation of α-acetochlorosugars12
and acid chlorides, particularly those derived from acetylated monocarboxylic acid sugars12,13
and acetylated amino acids.14
In addition, the ortho
derivatives of formic acid
may be prepared from dichloromethyl methyl ether
With aromatic compounds, dichloromethyl methyl ether
reacts under Friedel-Crafts conditions followed by hydrolysis to give the corresponding aromatic aldehydes.10,16,17
This preparation is referenced from:
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