JPS607977B2 - Method for producing P-aminobenzaldehyde - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing P-aminobenzaldehyde.

More specifically, the present invention relates to a method for producing P-aminobenzaldehyde by reacting P-nitrotoluene with sodium polysulfide in the presence of an aprotic polar compound.

P-aminobenzaldehyde is a compound useful as an intermediate raw material for pharmaceuticals, agricultural chemicals, etc., and its demand is increasing year by year.

Conventionally, a method for producing P-aminobenzaldehyde by reacting P-nitrotoluene and sodium polysulfide is known. For example, in Organic Synthesis Collective Volume 4, page 31, sulfur is added to sodium sulfide, and then water A method for producing P-aminobenzaldehyde by reacting sodium polysulfide prepared by adding sodium oxide with P-nitrotoluene is described.

However, this method has a low yield, with only 40 to 5
Only P-aminobenzaldehyde is obtained with a yield of 0%. The present inventors have repeatedly studied a method for producing P-aminobenzaldehyde using P-nitrotoluene as a raw material, eliminating these drawbacks. The present invention was achieved by discovering that P-aminobenzaldehyde can be obtained in good yield by reacting with sodium polysulfide in the presence of an aprotic polar compound.

That is, the gist of the present invention is to produce P-aminobenzaldehyde using P-nitrotoluene as a raw material.
This method is characterized in that nitrotoluene is reacted with sodium polysulfide in an alcohol-alkaline aqueous mixed solvent in the presence of an aprotic compound.

The method of producing P-aminobenzaldehyde by reacting P-nitrotoluene with sodium polysulfide in the present invention is described in the previously filed "Method for producing P-aminobenzaldehyde" (filed on September 7, 1972). Although it is efficient and convenient to use such a method, it is not particularly limited to this method.

That is, in order to produce P-aminobenzaldehyde by reacting P-nitrotoluene with sodium polysulfide, even when reacting using sodium polysulfide prepared by a conventionally known method, it is necessary to react in the presence of the aprotic failure compound of the present invention. If the reaction is carried out in an alcohol-alkaline aqueous mixed solvent, the yield will be significantly improved. The alcohols used in the present invention include methanol, ethanol, ethylene glycol, ethylene glycol monomethyl ether, catechol, ethylene glycol monoethyl ether, and mixtures thereof, among which alcohols containing at least 80% ethanol are used. Good yields were obtained when used.

The aprotic trough compound used in the present invention is N・N-
Dimethylformamide, NON-diethylformamide, N-N-diphenylformamide, dimethyl sulfoxide, tris(trimethylamino)phosphate "Refers to polar compounds that do not dissociate H+, such as tetrahydrofuran and acetonitrile.

When these aprotic polar compounds are present in an amount of 0.01 to 1% by weight based on P-nitrotoluene, the yield is significantly improved. If it is less than this, there will be no effect, and even if it exceeds 10%, not only will there be no significant improvement, but the yield will actually decrease. Among these, particularly excellent effects were obtained with N.N-dimethylformamide. The present invention will be explained in more detail below using Examples and Comparative Examples.

Example 1 Sodium hydroxide (0.12 m
Add an aqueous solution of 5 moles) dissolved in 10 parts of water, and add 4
5do, hydrogen sulfide 4.1 moles (0.121 mol)
The reaction was allowed to proceed for 1 hour.

The obtained sodium bisulfide aqueous solution was placed in a flask, and 9.1 moles (0.228 mol) of sodium hydroxide and 547 moles of water were added thereto to prepare a sodium sulfide aqueous solution.
This sodium sulfide aqueous solution contains 14.5 sulfur (0.45
mole) and reacted for 1 hour at 80 oo to obtain a sodium polysulfide aqueous solution.
When expressed as x, it corresponded to x=3.24. P
Nitrotoluene 66.7 mols (0.487 mol), ethanol 223 mols, N.N-dimethylformamide 2.7 mols.
P-nitrotoluene (4.1% by weight based on P-nitrotoluene) was added to the flask, dissolved and maintained at 8,000 ℃, and added to the sodium polysulfide aqueous solution with 51 % of a 50% sodium hydroxide aqueous solution.
．． The entire amount of the alkaline aqueous solution was added dropwise over 2 hours. After the dropwise addition was completed, the reaction mixture was further refluxed for 2 hours to complete the reaction. The reaction product was steam distilled to purify P-aminobenzaldehyde, yielding 42.3 mmol (0.350 mol). The yield is 71.8 for P-nitrotoluene.
%Met. Example 2 P-aminobenzaldehyde was prepared in the same manner as in Example 1, except that 2.3 liters of acetonitrile (3.4% by weight based on P-nitrotoluene) was used instead of NON-dimethylformamide. 312 mol) was obtained.

P-nit. The yield based on toluene was 64.8%. Example 3 P-aminobenzaldehyde 38.3% was prepared in the same manner as in Example 1 except that 3.2% of dimethyl sulfoxide (4% by weight based on P-nitrotoluene) was used instead of N'N-dimethylformamide. Yield (0.317 mol) was obtained.

The yield based on P-nitrotoluene was 65.8%. Example 4 30 moles (0.125 moles) of sodium sulfide nonahydrate was dissolved in 600 moles of water, and 15 moles (0.47 moles) of sulfur was dissolved in this aqueous solution.
mol) was added and reacted for 1 hour at 8,000 mol to form sodium polysulfide, and further 27 molar of sodium hydroxide was added to form an alkaline aqueous solution.

This aqueous solution was mixed with 50 moles of P-nitrotoluene (0.36 mol), 232 moles of ethanol and 4.2 moles of N.N-dimethylformamide (8.4% by weight relative to P-nitrotoluene).
) was added dropwise over 2 hours while maintaining the temperature at 8.0. After the dropwise addition was completed, the reaction mixture was further refluxed for 2 hours to complete the reaction. The amount of P-aminobenzaldehyde obtained was 27.9 moles (0.23 mol), and the yield was 64% based on P-nitrotoluene. Comparative Example 1 Example 1 except that N.N-dimethylformamide was not added.
It reacted exactly the same way.

The yield of the obtained P-aminobenzaldehyde was 56% based on P-nitrotoluene. Comparative Example 2 Example 4 except that NON-dimethylformamide was not added.
I reacted in the same way.

Claims (1)

[Claims] 1. In producing P-aminobenzaldehyde using P-nitrotoluene as a raw material, P-nitrotoluene is reacted with sodium polysulfide in an alcohol-alkali aqueous mixed solvent in the presence of an aprotic polar compound. Method for producing P-aminobenzaldehyde. 2. The method of claim 1, wherein the alcohol contains at least 80% ethanol. 3. The method according to claim 1, wherein the aprotic polar compound is present in an amount of 0.01 to 10% by weight based on P-nitrotoluene. 4. The method according to claim 1, wherein the aprotic polar solvent is N.N-dimethylformamide. 5. The method according to claim 1, wherein sodium polysulfide whose chemical formula is represented by Na_2Sx is x=2 to 5.