Org. Synth. 1960, 40, 27
DOI: 10.15227/orgsyn.040.0027
DIETHYL BIS(HYDROXYMETHYL)MALONATE
[Malonic acid, bis(hydroxymethyl)-, diethyl ester]
Submitted by Paul Block, Jr.
1
Checked by Melvin S. Newman and Reinhardt Stein.
1. Procedure
Formaldehyde solution equivalent to
60 g. of formaldehyde (2 moles) (Note 1) and
8 g. of potassium bicarbonate (small crystals) are placed in an
800-ml. beaker standing in a
water bath at 20° in a
hood. Mechanical stirring is started and
160 g. (1 mole) of diethyl malonate (Note 2) is added dropwise during about 40–50 min., at such a rate that the temperature of the reaction mixture is held at 25–30°. Stirring is continued for 1 hour. The reaction mixture is transferred to a
separatory funnel. A saturated solution of
ammonium sulfate (320 ml.) (Note 3) is added and the mixture is extracted with
320 ml. of ether. The ethereal extract, dried for 1 hour with anhydrous
sodium sulfate (20 g.), is filtered into a
1-l., three-necked flask through a
fluted filter paper. The
sodium sulfate and paper are washed with
50 ml. of anhydrous ether. The flask (fitted with a
thermometer reaching to the bottom, a condenser set for downward distillation; third neck closed) is placed in a suitable heating bath
(Note 4). Boiling chips are introduced and the ether is distilled until the temperature of the liquid has risen to 45–50°. The heating bath is then removed and the distillation assembly is replaced by a glass tube (about 4 mm. I.D.) reaching to the bottom of the flask and closed by a piece of rubber tubing and a screw clamp. An aspirator is now connected to the third neck of the flask. Vacuum is applied and volatile material is removed until the pressure falls to 20–30 mm. The temperature of the contents of the flask is brought to 40° and maintained there until crystallization begins and for an additional 30 minutes
(Note 5).
Isopropyl ether (500 ml.) (Note 6) is added. The mixture is warmed to 50° and swirled until the product (crystalline and oily) dissolves. The solution is transferred to an
Erlenmeyer flask, and cooled in ice water with stirring until a thick suspension of crystals results. The suspension is refrigerated for 1 hour, filtered with suction (
rubber dam), and the crystals are dried overnight at room temperature, and then in a
vacuum desiccator over
sulfuric acid. The yield of colorless crystals, m.p.
48–50°, is
158–166 g. (
72–75%). This product may be recrystallized from
isopropyl ether (3.5 volumes) with an
85% recovery to yield material with m.p.
50–52°. Melting points of
52–53° and
52° are reported.
2,3
2. Notes
1.
Exactly
3 ml. of formaldehyde solution is assayed by the method of U.S.P. XIII, and the result calculated to grams of
formaldehyde per milliliter of solution.
2.
The
diethyl malonate used boiled over a 2° range.
3.
Ammonium sulfate (175 g.) is added to 235 ml. of water, warmed until it is dissolved, and cooled.
4.
A
heating mantle or liquid bath may be used.
5.
The screw clamp may be adjusted so that there will be a spattering on the upper, cool part of the flask, while the pressure is still maintained below 30 mm. Under these conditions, the initiation of crystallization is speeded.
6.
A practical grade is adequate, but is should be peroxide-free.
3. Discussion
The only reported method of preparation of
diethyl bis(hydroxymethyl)malonate is by the reaction described here.
2,34. Use of Diethyl Bis(hydroxymethyl)malonate
Diethyl bis(hydroxymethyl)malonate is a useful intermediate for preparing substituted malonic esters, acrylic esters, and isobutyric esters.
2,4
This preparation is referenced from:
Appendix
Chemical Abstracts Nomenclature (Collective Index Number);
(Registry Number)
sulfuric acid (7664-93-9)
ether (60-29-7)
formaldehyde (50-00-0)
sodium sulfate (7757-82-6)
diethyl malonate (105-53-3)
ammonium sulfate (7783-20-2)
isopropyl ether (108-20-3)
potassium bicarbonate (298-14-6)
Diethyl bis(hydroxymethyl)malonate,
Malonic acid, bis(hydroxymethyl)-, diethyl ester (20605-01-0)
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