JPS5953270B2 - Method for producing acetal compounds - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing an acetal compound.

Specifically, the present invention relates to a method for producing a 1,3-dicarbonyl compound in which only one carbonyl group is acetalized. Conventionally, 1,3-
It goes without saying that dicarbonyl compounds are widely used as raw materials for various chemical reactions.

During these reactions, it is often desirable to selectively protect only one of the carbonyl groups in relation to the next reaction, but no suitable method has hitherto been available. For example, as a method commonly used for protecting ketones, there is a method in which a 1,3-dicarbonyl compound and ethylene glycol are reacted in the presence of an acid catalyst. It is difficult to selectively protect only groups, and there are also many side reactions and yields are low. In view of these circumstances, the inventors of the present invention have conducted intensive research and have found 1, 3
The present invention was achieved based on the finding that the object can be achieved by reacting a dicarbonyl compound with a specific compound in the presence of a specific catalyst. In other words, the gist of the present invention is the following general formula... ■X / \ / \ R, xE? R3(I) (wherein R represents a hydrocarbon residue; R represents a hydrogen atom or a hydrocarbon residue; R represents a hydrocarbon residue or an alkoxy group;

However, when R represents a hydrocarbon residue, R represents a hydrocarbon residue. 1,3-dicarbonyl compound represented by the following general formula () and ethylene carbonate represented by the following general formula () are reacted in the presence of a quaternary ammonium halide or an alkali metal halide.
In the formula, R1 to R have the same meanings as above.

) consists in a method for producing an acetal compound. The present invention will be explained in detail below. The 1,3-dicarbonyl compound L, which is a raw material for the method of the present invention, has the general formula (1
) can be used.

There are no particular restrictions on R, as long as it is a hydrocarbon water, and it usually has 1 to 10 carbon atoms.

Specifically, for example, alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, hexyl, etc.: phenyl,
Examples include aryl groups such as tolyl and xylyl; cycloalkyl groups such as cyclohexyl; and aralkyl groups such as benzyl. 8i #S Suiha” fma? is a hydrocarbon residual flower, but the palm of the hand - f blue! E. Han Zhangji-J=many!
It is a hydrogen sulfide residue, and shi( is the main atom s!11(
Alki Jre basic prisoner W with number of palms 1 to 6
As for R, JlIt Hayamoto Kei Co., Ltd.,! 8a'
It is a xyl group, but it is usually a char-J? 9? I is an epihydrogen residue or an alkoxy group.

Specifically, in addition to those exemplified by R1 above, alkoxy groups such as methoxy, ethoxy, propoxy, and octyloxy are listed. 1,,,3- represented by the general formula (1) Specifically, as the dicarbonyl compound, $-methyl-2,4-pentanedione, 3-benzyl
Jyod Q, 4-pentanedione, ethyl acetoacetate, 3-
Examples include ethyl oxopentanoate.

The method of the invention requires the presence of a specific compound as a catalyst.

Catalysts include quaternary ammonium halides or alkali metal halides. As the quaternary ammonium halide, well-known ones can be used without particular limitations.

Specifically, for example, quaternary ammonium halides made from tertiary amines and alkyl halides or aryl halides, such as tetramethylammonium monochloride, tetramethylammonium bromide, tetramethylammonium iodide, tetraethylammonium iodide, trimethyl Examples include ethyl ammonium iodide, trimethylphenylammonium iodide, triethylcetylammonium bromide, and the like.

As the alkali metal halide, well-known ones can be used without particular limitations.

Specifically, examples include lithium chloride, lithium bromide, lithium iodide, sodium fluoride, sodium chloride, sodium bromide, sodium iodide, potassium fluoride, potassium chloride, potassium bromide, potassium iodide, etc. I can do it. In the method of the present invention, the 1,3-dicarbonyl compound and ethylene carbonate are reacted in the presence of a catalyst.

The amount of the catalyst is not particularly limited, but is usually 0.01 to 1 mol (per cyclic carbonate), preferably about 0.1 mol. There are no particular restrictions on the reaction method.

Usually, approximately 1 mol of ethylene carbonate is used per 1 mol of the 1,3-dicarbonyl compound, but ethylene carbonate may be used in an equivalent amount or more, or in large excess.

The reaction temperature is usually 130-220°C, preferably 150-220°C.
The temperature is 180°C.

There is no particular restriction on the reaction pressure.

It is convenient to carry out the reaction near normal pressure, but if a low boiling point solvent or the like is used, the reaction may be carried out under increased pressure. The reaction time varies depending on the type of raw materials, the type of catalyst, and the reaction temperature, but is about 15 minutes to 10 hours. During the reaction, no particular solvent is required, but if a solvent is used, it is preferable to use an aprotic inert solvent without a carbonyl group, such as diglyme or dimethoxyethane.

The method of the present invention has the following effects.

First, a product can be obtained in which only one carbonyl group of a 1,3-dicarbonyl compound is selectively acetalized.

Such products are extremely useful as synthetic intermediates. Furthermore, the method of the present invention has mild reaction conditions and also has a high product yield.

EXAMPLES The present invention will be described in more detail with reference to Examples below, but the present invention is not limited in any way by the Examples unless the gist of the invention is exceeded.

In the examples, "%" is based on weight unless otherwise specified. Examples 1 to 3 In the presence of 0.3 mm01 of the catalyst shown in Table 1, 2-methyl-
1,3-diphenyl-1,3-propanedione (715
1,3mm0I) and ethylene carbonate (35777
? , 4mm01) were heated under the conditions shown in Table 1 while stirring.

The product was separated by silica gel column chromatography (cyclohexane-acetone system) to obtain 2-(1-benzoylethyl)-2-phenyl-1,3-dioxolane in the yield shown in Table 1. Examples 4 to 6 In Example 1, 2-methyl-1,3-diphenyl-1,3-propanedione was changed to 2-benzyl-1,3-diphenyl-1,3-propanedione (3mm01), and In exactly the same way, 2-(1-benzoyl-2-
Phenyl)ethyl-2-phenyl-1,3-dioxolane was obtained in the yield shown in Table 2.

Examples 7 and 8 In the coexistence of 0.5mm01 of the catalyst shown in Table 3, ethyl acetoacetate (660W, 5mm01) and ethylene carbonate (447~, 5mm01) were produced at 150-155°C while removing ethanol, which is a by-product. After the heating reaction for the time shown in Table 3, the 2-ethoxycarbonylmethyl-2
-Methyl-1,3-dioxolane was obtained in the yield shown in Table 3.

Claims (1)

[Claims] 1 The following general formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) (In the formula, R_
1 represents a hydrocarbon residue, R_2 represents a hydrogen atom or a hydrocarbon residue, and R_3 represents a hydrocarbon residue or an alkoxy group. However, when R_3 is a hydrocarbon residue, R_2 represents a hydrocarbon residue. ) and ethylene carbonate represented by the following general formula (II) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (II) in the presence of quaternary ammonium halide or alkali metal halide. The following general formula (III) is characterized by the following reaction ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (
III) A method for producing an acetal compound represented by (wherein R_1 to R_3 have the same meanings as above).