JPS5865288A - Preparation of 4-alkoxy-1,3-dioxane-5-carbonitriles - Google Patents

Abstract

NEW MATERIAL:A compound shown by the formulaI(R is lower alkyl). EXAMPLE:4-Ethoxy-1,3-dioxane-5-carbonitrile. USE:Capable of being easily converted by hydrolysis, etherification, etc. into a raw material for synthesizing vitamin B1. PROCESS:A 3-alkoxy-2-propenenitrile shown by the formulaI(R is lower alkyl) is reacted with formaldehyde gas in the presence of boron trifluoride or its complex[e.g., BF3.(C2H5)2O)]in an aprotic solvent (e.g., dioxane) to give the desired compound shown by the formula II. The amount of the catalyst used is 0.001-10mol, preferably 0.005-1mol based on the compound shown by the formulaI, and the amount of the solvent is 5-100pts.wt. based on the compound shown by the formulaIto give a high yield. The reaction is carried out at 0- 300 deg.C, preferably normal temperature-250 deg.C for 1-24hrs.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides 4-alkoxy-1,3-dioxane-5-
This paper relates to a method for producing carbonitrile compounds.

The 4-alkoxy-1,ro-dioxane-5-carbonitrile produced in the present invention is.

This is a new compound represented by the general formula (wherein R represents a lower alkyl group). This compound is.

Conventional method 2 For example, vitamin B s combination by hydrolysis reaction, etherification reaction, alcoholysis reaction, etc.
It can be easily converted to JX fees.

For example, 4-alkoxy-1,3-dioxane-5-carbonyls and alcohol are mixed under an acid catalyst such as concentrated sulfuric acid, concentrated hydrochloric acid, hydrogen chloride, p-toluenesulfonic acid, solid acid, etc.
By performing the reaction at a temperature of 40 to 150°C, 2-dialkoxymethyl-6-alkoxypropanenitrile, 2-alkoxymethyleneno-5-alkoxypropanenitrile, 2-alkoxymethyleneno-5-alkoxypropanenitrile, which is known as a raw material for the synthesis of vitamin B1.
Propane nitriles such as -methylene, 6-dialkoxypropa/nitrile can be produced.

The present inventors discovered that 4-arthugis 1. Rhodioxane-5-carbo=) +)
By reacting 3-alkoxy-2-propenenitrile and aldehyde in the presence of an acid catalyst,
Discover what can be manufactured.

First applied for a patent for the invention (Japanese Patent Application No. 74194/1983)
did. However, the invention left room for improvement in terms of yield and selectivity of the target product.

As a result of subsequent research, the present inventors identified boron trifluoride or its complex salt as a catalyst.

If an aprotic solvent is used as the solvent and formaldehyde gas is used as the aldehyde.

It has been found that 4-alcoquine-1,3-dioxane-5-carbonitrile can be obtained with extremely high yield and high selectivity. □ That is, the present invention.

General formula % Formula % (However, in the formula, R represents a lower argyl group.) 2-Alkoxy 2-propenenitrile and formaldehyde gas are mixed in the presence of boron trifluoride or a complex salt thereof. It is characterized by being reacted in a solvent.

The present invention provides a method for producing 4-alcogine-1,3-diogizano-5-carbonitrile represented by the general formula (wherein R represents a lower argyl group).

The conventional method for producing 1,3-dioxanes by reacting an olefin substituted with an alkyl group, an aryl group, a halogen atom, etc. with an aldehyde in the presence of an acid catalyst is known as the Prince reaction. . However, the Prins reaction targeting the nitrile group-substituted olefin represented by the above general formula is not known, and even more so, if this special olefin is subjected to the Prins reaction, 4-alkoxy-1, represented by the above general formula, There is no literature that predicts that 3-dioxane-5-carbonitrile can be obtained.

Specific examples of 6-alkoxy-2-propenenitrile represented by the above general formula used in the present invention include 6-medoxy-2-propenenitrile, ro-ethoxy-2-propenenitrile, 3-n (also 1)- 7'ropoxy-2-
Propenni)! J le + sn (ir BeC still t
ert )-butoxy-2-propenenitrile and the like.

Examples of formaldehyde gas include paraformaldehyde, trioxane, and tetraoxane.

Porioxymethylene, hemiacetal, etc. are thermally decomposed and purified by conventional methods and then used.

Mataformaldehyde gas is preferably used in an amount of 1 to 20 mol, preferably 2 to 10 mol, per 1 liter of 3-alkoxy-2-propenenitrile.

The catalyst used in the present invention is selected from boron trifluoride or a complex salt thereof.
4Hg)201BFg・(OH3COOH)z,
DPI ・(OH30H) 2, BF3 ・(e□
H) 2° or BF3・C! 2H5NH2 and the like are useful.

The amount of these catalysts to be used is 0.001 to 10 mol, preferably 5 to 1 mol of O,[lO, per 1 mol of 3-alkoxy-2-flopennitrile. If the amount of catalyst used is less than the lower limit, the progress of the two reactions will be slow, while if it is more than the upper limit, the amount of by-products will increase.

The solvent used in the present invention is dioxane, tetrahydrofuran, dimethoxyethane, diethyl ether, diisopropyl ether, dibutyl ether insoluble in ether; benzene, toluene.

xylene, hexane, heptane, cyclohexane.

Hydrocarbon M medium such as cyclohebutane, tetralin, decalin, nitrobenzene: methylene chloride.

Halogenated hydrocarbon solvents such as chloroform, carbon tetrachloride, and 1,2-dichloroethane; Nitrile solvents such as acetonitrile, propionitrile, and benzonitrile;
Ester solvents such as methyl acetate, ethyl acetate, butyl acetate, methyl propionate, and ethyl bupionate; and aprotic solvents such as dimethyl sulfoxide and dimethyl formamide. These solvents are used in an amount of 5 to 1 part by weight per 1 part by weight of filtrate-alkoxy-2-propenenitrile.
Preferably, 00 parts by weight are used. If the amount of the solvent before use is less than the lower limit, the yield of the target product will decrease,
On the other hand, if it is greater than the upper limit.

Although the yield of the target product is not adversely affected, the amount of solvent recovered increases and is industrially uneconomical.

The reaction is carried out at 0 to 600°C, preferably from room temperature to 250°C.
It is carried out at a temperature of 1 to 24 hours under normal pressure to pressurized system.

The reaction operation in the present invention is not particularly limited.

For example, you can do the following:

After bubbling and absorbing formaldehyde gas into the solvent, the catalyst and filter-alkoxy 2-propenenitrile are added. Alternatively, a catalyst is made to exist in the solvent, formaldehyde gas is blown into the solvent, and then filtrate 2-propenyl-lyl* is added. Furthermore, after dissolving the alkoxy-2-propenenitrile in a solvent and adding a catalyst.

Inject formaldehyde gas.

The reaction of the present invention can be carried out either in a batchwise manner or in a continuous manner. Isolation of target product after reaction.

Purification is easily accomplished by appropriately employing operations such as filtration, extraction, and distillation.

Next, two examples of the present invention and a comparative example will be given.

Example 1 A 300 tne flask equipped with a thermometer, a calcium chloride reflux condenser, and a gas blowing tube and a dropping funnel was charged with 200 ii' of ethyl acetate, and 4.50 g (1 SO mmol) of formaldehyde gas was added at room temperature. was blown and absorbed, and then 0.851 (6 mmol) of 13F3.(C2H5)20 was added. Pour this mixture at 60°
After heating up to C, 6-medugishi ~ 2-propenenitrile 5
．． A solution prepared by dissolving 00 g (60 mmol) in m.ethyl acid 207 was added dropwise at 60''C over a period of 2 hours.

After stirring for an additional 2 hours at 60°C.

The reaction solution was quantitatively analyzed by gas chromatography.

Example 2 The amount of ethyl acetate charged was 130? , also BF3・(02
H5) An experiment was conducted in the same manner as in Example 1, except that the amount of ethyl acetate was changed to o-43y (3 mmol).

An experiment was conducted in the same manner as in Example 2.

Example 4 An experiment was carried out in the same manner as in Example 2, except that 0.56 g (3 mmol) of BF3.(OH3000H)2 was used as a catalyst.

Example 5 BF3・(C!H30H)2 was used as a catalyst at o,4oy(
The experiment was conducted in the same manner as in Example 2, except that 3 mmol) was used.

Comparative Example 1 Ethyl acetate 230 was added to a filter 007Ile flask equipped with a thermometer, a reflux condenser with a calcium chloride tube, and a dropping funnel.
7, room temperature] ζ, commercially available rose formaldehyde powder at 3.75 y (125 mmol) BF3・(C
0.71 y (5 mmol) of 2H5)20 was added.

After heating the mixture to 60°C, a solution containing 4.16 g (50 mmol) of 2-propenenitrile dissolved in total ethyl acetate 2C1' was added dropwise at 60°C over a period of 2 hours. After further stirring at 60°C for 2 hours, one reaction solution was quantitatively analyzed by gas chromatography.

Comparative Example 2 2 year old BF3 (0
2H5) The amount of preparation of 20 was reduced to 0.3 s y (2-
An experiment was carried out in the same manner as in Comparative Example 1, except that the amount of 5 mmol) was changed.

The results of Examples 1 to 5 and Comparative Examples 1 and 2 are shown in the secondary table.

Example 6 Dioxane 1301i+ was charged into a 500ml flask equipped with a thermometer, a reflux condenser with a calcium chloride tongue, and a dropping funnel with a gas blowing tube, and formaldehyde gas a, 5or (1so mmol) was blown into the flask at room temperature to absorb it, and then BF3 was added.・(02H5) 20 is o, a 3 y
(3 mmol) was added. After heating this mixture at 60'C, 3-ethquin-2-propendi)
A solution of 3 g (60 mmol) dissolved in radioxane 207 was added dropwise at 60° C. over a period of 2 hours. 2 more
After stirring for an hour at 60'C.

The reaction solution was quantitatively analyzed by gas chromatography.

As a result, the conversion rate of 6-nitoxy-2-propenyl-I-lyl was 97), 3-thi, and 4-nitoxy-1,3-dioxane-5-carbonitrile was 91. It was produced with a selectivity of 0%.

Example 7 Acetonitrile instead of dioxane and 6-nitoxy-2-propenenitrile
- Butoxy 2 - Propene nitrile 7, 50? An experiment was conducted in the same manner as in Example 6, except that C60 mmol) was used.

As a result, the conversion rate of 3-n-butoxy-2-propenenitrile was q 0.2%, and the conversion rate of 4-n-butoxy-1,6-
Shioxane-5-carbonitrile was produced with a selectivity of 91.8%.

Example 8 Methylene chloride was used instead of ethyl acetate, and the reaction temperature was changed to 4.
An experiment was conducted in the same manner as in Example 1, except that the temperature was maintained at 0°C, a methylene chloride solution of 6-medoxy-2-propenenitrile was added dropwise over 4 hours, and the mixture was stirred for an additional 8 hours.

As a result, the conversion rate of 3-methoxy-2-propenenitrile was 84.9%.

4-Methoxy-1,6-sioxane-5-carbonitrile was produced with a selectivity of 95.7%.

Example 9 In the same apparatus as in Example 1, BF30 was added to ethyl acetate 2002.
．． A solution containing 20 y (3 mmol) was prepared, and 4.5 0 y of formaldehyde gas was added at room temperature.
(1s.

mmol) was injected. After heating the mixture to 60°C, 3-methoxy-2-propenenitrile s. o o
A solution of y (bo mmol) dissolved in 20 g of ethyl acetate was added dropwise at 60°C over 2 hours.

After further stirring at 60°C for 2 hours, the reaction solution was quantitatively analyzed by gas chromatography.

As a result, the conversion rate of 3-methoxy-2-propenenitrile was 96, and 4-methoxy-1,3-dioxane-5-carbonitrile was produced with a selectivity of 96.1.

Patent applicant Ube Industries Co., Ltd. Continuation of page 1 @ Originated by Hiroshi Yoshida 5 U, 1978 Oaza Kogushi, Ube City Bukosan Co., Ltd. Central Research Laboratory [Phase] Inventor: Yoshiaki Kuroki 5 U, 1978 Oaza Kogushi, Ube City Bukosan Co., Ltd. Central Research Laboratory

Claims (1)

[Claims] 3-alkoxy-2-propenenitrile represented by the general formula % (wherein "R" represents a lower alkyl group) and formaldehyde gas are combined with boron trifluoride or its The reaction is carried out in an aprotic solvent in the presence of a complex salt. 4-alkoxy-1,3-dioxane-5- represented by the general formula (wherein R represents a lower alkyl group) Production method of carbonitrile.