JP3006941B2 - Method for producing 2,2,4,4,6-pentamethyl-2,3,4,5-tetrahydropyrimidine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing 2,2,4,4,6-pentamethyl-2,3,4,5-tetrahydropyrimidine which is useful as a raw material for a polymer light stabilizer or a pharmaceutical raw material. About.

[0002]

2. Description of the Related Art 2,2,4,4,6-Pentamethyl-2,3,4,5-tetrahydropyrimidine (hereinafter referred to as acetonine) is produced by using acetone or a condensate of acetone as a main raw material in the presence of a catalyst. Manufactured. As a method for producing acetonin, a method is disclosed in which at least one of acetone and / or an acidic condensate of acetone is reacted with ammonia using a carboxylate of iron as a catalyst (Japanese Patent Application Laid-Open No. 3-95163). In this method, not only a large amount of catalyst is required, but also excess ammonia is blown in over a long period of time, so that a raw material such as acetone is volatilized with the ammonia and is lost from the reaction vessel. In order to increase the production efficiency, it is necessary to collect these, and there is a drawback that equipment for the collection is required.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing acetonine in a short time with a small amount of by-products without requiring the addition of a solvent during the reaction. .

[0004]

SUMMARY OF THE INVENTION The present invention relates to a method for producing a condensate of acetone or at least one of acetone and ammonia.
(I) L _m MX _n (I) (wherein, M represents B, Al, Si, P, As, Ti, Pd or Pt, X represents a halogen atom, L represents a hydrogen atom or NR ¹ R ² R ³ R
⁴ (wherein, R ¹ , R ² , R ³ and R ⁴ are the same or different and represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms), m represents an integer of 1 to 3, and n represents Represents an integer from 3 to 6,
When m is 2 or more, L may be the same or different), characterized by reacting in the presence of a compound represented by 2,2,4,4,6-pentamethyl-2,3,4, The present invention relates to a method for producing 5-tetrahydropyrimidine.

Hereinafter, the present invention will be described in detail. Examples of the condensate of acetone used in the present invention include mesityl oxide, diacetone alcohol, holon, isophorone, and triacetone dialcohol.
These compounds may be used alone or as a mixture of two or more.

In the formula (I), examples of the alkyl group having 1 to 4 carbon atoms include methyl, ethyl, propyl, butyl, isopropyl, isobutyl and tert-butyl. Halogen atoms include fluorine, chlorine, bromine and iodine. Specific compounds represented by the formula (I), for example, tetrafluoroborate, ammonium tetrafluoroborate, tetramethylammonium tetrafluoroborate, tetrabutylammonium tetrafluoroborate, trimethylammonium tetrafluoroborate, Tetrachloroboric acid, ammonium tetrachloroborate, hexafluoroaluminic acid, ammonium hexafluoroaluminate, ammonium hexafluorosilicate, hexafluorophosphoric acid, ammonium hexafluorophosphate, tetramethylammonium hexafluorophosphate, hexafluorophosphoric acid Ammonium tetrabutylate, ammonium hexachlorophosphate, hexafluoroantimonic acid, ammonium hexafluorotitanate, ammonium tetrachloropalladate Bromide, ammonium tetrachloroplatinate, ammonium hexachloroplatinate and chloroplatinic acid, ammonium tetrafluoro chloroplatinic acid, ammonium hexafluoro platinum acid. These compounds can be used alone or as a mixture of two or more. In addition, when a solvate such as a hydrate exists in these compounds, it can be used, or may be used in the form of a solution such as an aqueous solution or an alcohol solution.

The compound (I) is used in a weight ratio of 0.0001 to 0.2, preferably 0.001 to 0.1, relative to the total weight of the raw materials. Acetone as raw material and / or
Alternatively, the molar ratio of the condensate of acetone and ammonia is not particularly limited, but considering the productivity of each reaction treatment, the molar ratio of ammonia to acetone and / or the condensate of acetone is from 0.01 to 0.01. 4, preferably 0.1 to 1.2. In the case of a condensate of acetone, the number of moles is calculated in terms of acetone.

[0008] The reaction is carried out under normal pressure to under pressure. When performed under pressure, the reaction pressure is determined by the composition and amount of the raw materials and the reaction temperature and is not particularly limited, but is usually from normal pressure to 10 atm, preferably from normal pressure to 3 atm. Done. The reaction temperature is from 0 ° C to 150 ° C, preferably from 30 ° C to 100 ° C. The reaction time is 30 minutes to 20 hours, and usually ends in 1 hour to 10 hours.
After completion of the reaction, the product, acetonine, is purified by a method commonly used in organic synthetic chemistry, such as filtration, extraction, washing, drying,
It can be isolated and purified by subjecting it to concentration, distillation, various types of chromatography and the like.

The reaction for producing acetonine is an equilibrium reaction accompanied by the production of water. Therefore, removing water to the outside of the reaction system works to promote the production of acetonine. In practicing the present invention, an operation of removing water out of the reaction system, for example, an operation of blowing a gas such as ammonia or nitrogen into the reaction system, or a molecular sieve,
An operation of causing a dehydrating agent such as anhydrous calcium sulfate, anhydrous calcium chloride or anhydrous sodium sulfate to be present in the reaction system may be used in combination.

In practicing the present invention, it is essentially unnecessary to use a solvent, but a solvent can be used if necessary. Any solvent may be used as long as it is inert to the reaction, and examples thereof include methanol, ethanol, butanol, hexane, cyclohexane, toluene, dichloroethane, and propylene glycol.

[0011] The use of acetonine is, for example, using 2,2,6,6-tetramethylpiperidine-4-acetone as a raw material.
ON (hereinafter, referred to as triacetone amine) has been synthesized (Japanese Patent Laid-Open No. 3-188065), and a polymeric light stabilizer has been synthesized using triacetone amine as a raw material (see `` Latest Polymer Additives ''). Technology, pp. 100-119, CMC, 1988
Year). Next, embodiments of the present invention will be described with reference to examples.

[0012]

EXAMPLES The product, triacetoneamine, was identified and quantified by comparison with a sample using gas chromatography. GC-12A (manufactured by Shimadzu Corporation) was used for gas chromatography, and a column packed with a PEG-HT filler was used as a column.

Example 1 A pressure-resistant reaction vessel was charged with acetone (30 mL, 23.2 g), ammonia (4.68 g), and ammonium tetrafluoroborate (43 mg), and reacted at 50 ° C. with stirring for 5 hours.

When the obtained reaction mixture was quantitatively analyzed using gas chromatography, it was found that 16.7 g of acetonine was produced in the reaction mixture. After the low-boiling substances were distilled off under reduced pressure, 14.7 g of acetonine was obtained by distillation (yield 82% calculated based on the amount of consumed acetone).

Example 2 The reaction was carried out in the same manner as in Example 1 except that 215 mg of ammonium tetrafluoroborate was used. As a result, it was found that 14.1 g of acetonine and 0.82 g of triacetoneamine were formed in the reaction mixture.

Example 3 A reaction was carried out in the same manner as in Example 1 except that 67 mg of ammonium hexafluorophosphate was used instead of ammonium tetrafluoroborate. As a result, 16.5 g of acetonine was found in the reaction mixture. .

Example 4 A reaction was carried out in the same manner as in Example 1 except that 73 mg of ammonium hexafluorosilicate was used instead of ammonium tetrafluoroborate. As a result, 15.4 g of acetonine was found in the reaction mixture. .

Example 5 A reaction was carried out in the same manner as in Example 1 except that 116 mg of ammonium tetrachloropalladate was used instead of ammonium tetrafluoroborate. The reaction mixture contained 15.9 g of acetonine and 1.3 g of triacetoneamine in the reaction mixture. Was found.

Example 6 A reaction was carried out in the same manner as in Example 1 except that 182 mg of ammonium hexafluoroplatinate was used instead of ammonium tetrafluoroborate. The reaction mixture contained 15.6 g of acetonine and 1.3 g of triacetoneamine in the reaction mixture. Was found. Table 1 shows the yields of acetonine and triacetoneamine shown in the above Examples.

[0020]

[Table 1]

A) Yield calculated based on the amount of acetone consumed. b) Yield calculated based on the amount of ammonia consumed.

[0022]

Industrial Applicability According to the present invention, 2,2,4,4,6-pentamethyl-2,3,2,4,6-pentamethyl-2,3,3 Provided is a method for producing 4,4,5-tetrahydropyrimidine (acetonin).

Claims (1)

(57) [Claims] 1. A condensation product or at least one of formula (I) in L _m MX _n (I) [wherein the ammonia acetone acetone, M is, B, Al, Si, P , As, Ti, Pd or X represents a halogen atom, L represents a hydrogen atom or NR ¹ R ² R ³ R
⁴ (wherein, R ¹ , R ² , R ³ and R ⁴ are the same or different and represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms), m represents an integer of 1 to 3, and n represents Represents an integer from 3 to 6,
When m is 2 or more, L may be the same or different), characterized by reacting in the presence of a compound represented by 2,2,4,4,6-pentamethyl-2,3,4, A method for producing 5-tetrahydropyrimidine.