JPS6011473A - Preparation of 5-(phenylmethylene)-2,4-imidazolidinedione - Google Patents

Abstract

PURPOSE:To obtain the titled compound useful as an intermediate for preparing phenylalanine economically advantageously, by reacting 2,4-imidazolidinedione with benzaldehyde by the use of inexpensive ammonia as a condensation agent. CONSTITUTION:2,4-Imidazolidinedione is reacted with benzaldehyde by the use of ammonia as a condensation agent at 50-150 deg.C, preferably at 80-110 deg.C, to give the titled compound. Water is preferable as a solvent, but a mixed solvent of water and a water-soluble organic solvent such as an alcohol, nitrile, etc. may be used. Ammonia gas, ammonia water, ammonium carbonate, etc. may be used as ammonia, and an amount of it used is 0.01-10 times, preferably 0.01- 2.0 times as much ammonia as one of the raw materials used in a smaller amount by molar quantity. A molar ratio of the raw materials of the former/the latter used is 0.7-1.4.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for industrially producing 5-(phenylmethylene)-2°4-imidazolidinedione (hereinafter abbreviated as PLDN). More specifically, the present invention provides 2,4-imidazolidinedione (hereinafter referred to as ID
The present invention relates to a method for producing BzA by condensation of BzA (abbreviated as BzA hereinafter) and Penzalert (abbreviated as BzA hereinafter).

Conventionally, PLDN has been produced by condensing equimolar amounts of IDN and BZA at 80 to 90°C in the presence of 1.5 times the mole of monoethanolamine in an aqueous solution (U.S. Pat. No. 2,861.079). No.) Oyobi IDN,! :BZA
in acetic anhydride! A method of condensing at 125 to 185°C in the presence of at least equimolar sodium acetate to DN and then adding water to take out PLDN (Japanese Patent Application Laid-open No. 4
9-54869) is known.

However, although all of the above methods achieve a good yield of 90% or more, the former requires the use of a large amount of expensive monoethanolamine as a condensing agent, which requires a recovery step. Since recovery is from a dilute aqueous solution, energy costs are high, and
This is extremely disadvantageous from an industrial perspective, such as loss of monoethanolamine into wastewater and wastewater treatment. In addition, the latter requires the use of expensive solvents such as acetic anhydride.
A recovery process is still necessary, and the water produced during dispensing consumes acetic anhydride, which is economically disadvantageous.In addition, there are problems with the treatment of the acetic acid produced at this time, making it difficult for industrial use. This is extremely disadvantageous as a manufacturing method.

Therefore, the present inventors have conducted extensive research on a method that can carry out the condensation of IDN and BZA in a high yield and industrially advantageously, and have discovered that ammonia can be an excellent condensing agent. I was able to complete it. That is, the present invention is an improved method for producing PLDN, which comprises condensing IDN and BZA in the presence of ammonia.

IDN used as one raw material in the method of the present invention
is usually carried out using known methods such as those described in Japanese Patent Publication No. 89-24807 or Organic Synthetic Chemistry, Vol. 29, No. 12, page 1142.
It is easily synthesized by the Bergs method. Further, BZA used as a raw material for Mo-man may be a common commercially available product. Equimolar ratios of IDN and BZA are used. It is okay to have an excess of either one, but usually I.D.
As the N/BZA molar ratio, 0.7 to 1.4 is used. Even if the reaction exceeds this range, it can be carried out, but in that case, the excess raw material will remain unreacted, and it will be necessary to recover and reuse it, or to reuse the F solution after PLDN separation.

The ammonia used in carrying out the method of the present invention includes, for example, ammonia gas, liquid ammonia, aqueous ammonia, or ammonium salts that easily decompose to produce ammonia, such as ammonium carbonate, ammonium bicarbonate, Ammonium acetate, ammonium carbamate, ammonium cyanide, etc. are used, and the amount used is I
0.01 to 10 times the mole of ammonia, preferably 0.1 to 2.
0x molar is used.

If the amount of ammonia is less than 0.01 Po mole, the reaction rate will be slow, and if it is more than 10 times the amount, side reactions of BZA will occur, which is disadvantageous.

The reaction temperature in the method of the present invention is 50 to 150°C, preferably 80 to 110°C, and the reaction time varies depending on the reaction temperature, but the reaction is completed in about 8 to 10 hours.

The solvent used in the method of the present invention is preferably water, but there is no problem in using a mixed solvent with a water-soluble organic solvent such as alcohols, nitriles, ethers, etc. There is no particular restriction on the amount of solvent used, and the reaction system may be homogeneous or heterogeneous.

The summary of the operations in the present invention is iDN.

BZA and ammonia are charged into a reaction vessel together with a solvent, and heat condensation is carried out at a predetermined reaction temperature and reaction time. After completion of the reaction, PLDN can be easily obtained in a substantially quantitative yield by cooling the reaction mixture as it is or after neutralization, and passing the precipitated crystals through the mouth.

There is no particular restriction on the operating pressure when carrying out the method of the present invention, and the process can be carried out either at normal pressure or under increased pressure. The operation can be carried out batchwise or continuously.

Next, the present invention will be explained in more detail with reference to Examples.
The present invention is not limited by these Examples.

Example 1 In a 1 ton flask equipped with a stirrer and a reflux condenser, 2.
Add 120 y of 4-imidazolidinedione and 10 6 y of benzaldehyde along with 850 y of water. After adding 7 fl of 25% by weight aqueous ammonia, the mixture was heated and reacted at 90° C. for 5 hours. The reaction mixture was cooled to room temperature, and the precipitated crystals were filtered through the mouth and washed with water to obtain 1 white crystal of 5-(phenylmethylene)-2,4-imidazolidinedione.
87y was obtained. When analyzed by liquid chromatography, the purity was 99.0% by weight, and the yield based on benzaldehyde was 98.5%.

Example 2.3 The same operation as in Example 1 was performed except that the amount of raw materials charged and the reaction conditions were changed as shown in Table 1, and the results shown in Table 1 were obtained.

Example 4 2,4-
imidazolidinedione 95y1 benzaldehyde 106
y, 25% by weight ammonia water (34f), 150 ml of water, and 150 rnt of methanol were charged, and after sealing, the reactor was heated, stirred, and reacted under pressure at 105°C for 3 hours. After opening, the reaction mixture was concentrated under reduced pressure, cooled to room temperature, and the precipitated crystals were filtered and washed with water, resulting in a purity of 98.5% by weight.
119f of white crystals of 5-(phenylmethylene)-2,4-imidazolidinedione were obtained, and the yield based on 2,4-imidazolidinedione was 98.7%.

Claims (1)

[Claims] 2.4-imidazolidinedione and benzaldehyde,
5- characterized by condensation in the presence of ammonia
A method for producing (phenylmethylene)-2°4-imidazolidinedione.