JPS60161978A - Preparation of thiophene compound - Google Patents

Abstract

PURPOSE:To obtain 2-amino-3-cyano-4-hydroxythiophene compound useful as an intermediate for dyes, etc., by reacting thioglycolic acid or an ester thereof with malononitrile in the presence of a basic compound. CONSTITUTION:A compound expressed by formula I (R is H or lower alkyl) is reacted with malononitrile in the presence of a basic compound, e.g. sodium ethylate, sodium methylate, sodium hydroxide or piperidine, to give a 2-amino- 3-cyano-4-hydroxythiophene compound. Alternatively, a compound expressed by formula II (X is Cl or Br) as a starting material may be reacted with sodium hydrosulfide to form the compound expressed by formula I in the reaction system, and the malononitrile is then added thereto to carry out the reaction in the same manner as described above. In both cases, the above-mentioned compounds are preferably reacted in water or a lower alcohol at -10-+20 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a 2-amino-3ddiano-4-hydroxythiophene compound.

More specifically, formula (1) % formula % (1) [In formula (1), R is a 2-amino-3 characterized by reacting a hydrogen atom or a lower alkyl group with lononitrile in the presence of a basic compound. - A method for producing a cyano-4-hydroxythiophene compound.

The thiophene compound obtained by the method of the present invention is a compound useful as a raw material and intermediate for dyes and organic compounds.

In the present invention, the alkyl group represented by R in general formula (1) includes a methyl group, ethyl group, n-propyl group, 1so-propyl group, n-butyl group, 1so-butyl group, n-pentyl group. , n-hexyl group, etc. In addition, as basic compounds, sodium methylate,
Alcolades such as sodium ethylate, inorganic compounds such as sodium hydroxide, potassium hydroxide, soda ash, etc.
1 dine, piperidine, dimethylformamide, triethylamine, picoline, morpholine, N,N-dimethylaniline, 1,4-diazabicyclo[2,2,2]octane (DABCO), 1,8-diazabicyclo(5,4,
0) -7-undecene or general formula (II)
) Chills may be produced and used. In that case, the reaction between the compound of formula (II) and sodium hydrogen sulfide, and the reaction between water nitrile and water nitrile, is carried out at -io°C to 60'C, preferably -5°C to
Perform at 20°C. In addition, as a reaction solvent, water, methanol,
0.8 malononitrile per 1 mole of Examples in the presence of ethanol, n-propertool, 1so-propertool, n-butanol, N,N-dimethylformamide, etc.
-1.2 molar ratio, preferably 0.9-1.1 molar ratio.

After the reaction is completed, if necessary, adjust the pH to 6 to 9 with acid, and then evaporate the solvent under reduced pressure.
A cyano-4-hydroxythiophene compound is obtained.

Further, these reaction solutions can be used as they are in the next reaction step.

EXAMPLES Hereinafter, the present invention will be explained in detail with reference to Examples, but the present invention is not limited to the Examples.

[Example-1] After dissolving 35 g of sodium ethylate in 400 g of ethanol, 33 g of malononitrile was dissolved in 20 g of ethanol.
was added dropwise at 0°C. After holding at 0°C for 1 hour, it was washed with ethanol. 200m7 of water for the furnace block! 2-amino-3-
Cyano-4-hydroxythiophene aog was obtained. Yield 85%.

[Example-2] After 42 g of caustic soda was dissolved in 200 y of water and cooled to 5° C., 359 g of malononitrile was added dropwise thereto. After holding at 5°C for 1 hour, 50g of thioglycolic acid was added and
The reaction was carried out at ℃ for 2 hours. After completion, P with 80g of 35% hydrochloric acid.
After adding H7, 250g of water was distilled off, filtered, and 2-
Amino-3-cyano-4-hydroxythiophene62.
I got a 9. Yield 83%.

[Example-3] 27 g of sodium methylate was dissolved in 200 methanol, cooled to 0°C, and malononitrile 331/
Methanol 207! A solution dissolved in was added. After holding at 0°C for 1 hour, thioglycolic acid methyl ester 5
3y was added and reacted at 0°C for 1 hour. Then, after filtering, washing with methanol, and dissolving the mud mass in 100 ml of water,
Thi-hydrochloric acid48. j7 was added to adjust the pH to 7, and 100 g of water was distilled off and filtered to obtain 61.9 g of 2-amino-3-cyano-4-hydroxythiophene. Yield 87%.

[Example-4] 33 g of malononitrile was added to a mixed solution of 50 g of methanol and 20.9 g of piperidine, and then 60 g of thioglycolic acid ethyl ester was added at 5°C. After reacting at 5°C for 1 hour and at 20°C for 1 hour, the organic solvent was distilled off under reduced pressure to obtain 2-amino-3-cyano-4-hydroxythiophene 61. I got an i7. Yield 87%.

[Example-5] 569 g of sodium hydrogen sulfide in 200 g of 50% methanol aqueous solution
was dissolved. 75 g of monochloroacetic acid n-butyl ester was added dropwise at 0°C, and the reaction was carried out at 0°C for 30 minutes to produce thio f IJ cholic acid n-butyl ester in the reaction system. Then, a solution prepared by dissolving 33 g of malononitrile in 53 p of pyridine was added at 0°C. 2 hours at 0℃, 20℃
After reacting for 1 hour, the solvent 150I was distilled off under reduced pressure,
2-amino-3-cyano-4-hydroxythiophene 5
8g was obtained. Yield 83%.

patent applicant Mitsui Toatsu Chemical Co., Ltd.

Claims (1)

[Claims] 1. General formula (1) % formula % (1) [In formula (1), R represents an ice atom or a lower alkyl group formed by reacting malonitrile with malonitrile in the presence of a basic compound. A method for producing a 2-amino-3-cyano-4-hydroxythiophene compound. 2. General formula (II) The reaction to produce the 2-amino-3-cyano-4-hydroxythiophene compound is carried out at -10°C to 20°C.The reaction is carried out in water or a lower alcohol. The method according to claim 1 or 2, which is carried out in accordance with claim 1 or 2.