JPH0796551B2 - 2- (α-Alkoxyimino) ethylthiophene derivative and method for producing the same - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION The present invention has the general formula (I) (In the formula, R represents an alkyl group having 1 to 4 carbon atoms and Z represents an acetyl group or a carboxyl group.) A novel 2- (α-alkoxyimino) ethylthiophene derivative and a method for producing the same.

That is, the present invention has the general formula (II) (In the formula, R is the same as the above.) A novel compound 5-acetyl-2- (α-alkoxyimino) ethylthiophene represented by the general formula (III) (In the formula, R is the same as the above.) The novel compound 5- (α-alkoxyimino)
TECHNICAL FIELD The present invention relates to ethyl-2-thiophenecarboxylic acid and methods for producing these.

The novel 2- (α-alkoxyimino) ethylthiophene derivatives represented by the above general formulas (II) and (III), respectively, can be used as important intermediates for producing pharmaceuticals, agricultural chemicals and the like. For example, 5-acetyl-2-
5- (α-Alkoxyimino) ethyl-2-thiophenecarboxylic acid can be obtained by oxidizing (α-alkoxyimino) ethylthiophene by a haloform reaction. By hydrolyzing this novel compound with an acid, 5-acetyl-2- which is a known compound can be easily obtained.
Thiofenecarboxylic acid can be obtained. This compound is disclosed, for example, in JP-A-50-25562 and JP-A-50-760.
Arrhythmia, various heart diseases and antihypertensive agent described in JP-A-69, which is a thienyl thiazolyl thioamino alcohol derivative. Is an important intermediate.

Further, by hydrolysis of 5-acetyl-2- (α-alkoxyimino) ethylthiophene, which is the novel compound according to the present invention, with an acid, a known compound of 2,5
-Diacetylthiophene can be easily obtained.

However, there has been heretofore no known method capable of industrially easily producing 5-acetyl-2-thiophenecarboxylic acid and 2,5-diacetylthiophene in high yield.
For example, as a method for producing 5-acetyl-2-thiophenecarboxylic acid, a method by hydrolysis of 5-cyano-2-acetylthiophene (J. Chem. Soc., 1937 , 911), 2,5-
Method by oxidation of diacetylthiophene (J. Am. Chem. So
c., 69 , 1012 (1947)), a method by acylation of 2-thenoyl ester (Ann.der Chem., 1 (1962)), carboxyl of 2-methyl-2'-thienyl-1,3-dioxolane. Although a method using a chemical reaction is known, none of them is industrially preferable from the viewpoint of raw material, reaction safety and controllability.

So, in order to solve the problems in these methods,
As described in JP-A-53-23963 and JP-A-53-141264, 5-acetyl-2-thienylacetic acid or its ester obtained by acetylation of 2-thienylacetic acid is oxidized. Although a method has been proposed, this method is not always easy to control the reaction.

Further, as a method for producing the 2,5-diacetylthiophene, for example, a method of acetylating 2-acetylthiophene (J. Am. Chem. Soc., 69 , 1012 (1947)) is known. However, the yield is extremely low.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention The inventors of the present invention have conducted diligent research to find out an industrially advantageous method for producing 5-acetyl-2-thiophenecarboxylic acid and 2,5-diacetylthiophene, for example. Attention was paid to the use of 2-acetylthiophene, which is easily available as an industrial raw material.

However, 2-acetylthiophene has a low electron density in the thiophene ring due to the electron-absorbing acetyl group, and thus it is difficult to carry out the electrophilic substitution reaction at the 5-position. For example, as described above, the method for directly acetylating 2-acetylthiophene includes:
2,5-Diacetylthiophene can only be obtained in very low yields.

Then, as a result of diligent research on the derivative which raises the electron density in the thiophene ring of 2-acetylthiophene, the present inventors have found that 2-acetylthiophene oxime is O-
Alkylation of the acetyl group into an electron-donating group α-
When converted to an alkoxyiminoethyl group to give 2- (α-alkoxyimino) ethylthiophene, this compound is easily and highly yielded by an electrophilic substitution reaction to give 5
It has been found to give acetyl-substituted compounds.

That is, 2- (α-alkoxyimino) ethylthiophene is easily converted to 5% by acetic anhydride or the like for the reason described above.
-Acetylated at the position to give 5-acetyl-2- (α-
Alkoxyimino) ethylthiophene is converted. By hydrolyzing this compound with an acid, known 2,
5-Diacetylthiophene can be obtained. Also,
By oxidizing the acetyl group at the 5-position of 5-acetyl-2- (α-alkoxyimino) ethylthiophene to a carboxyl group by the haloform reaction, 5- (α-alkoxyimino) ethyl-2-thiophenecarboxylic acid is obtained. Further, the known 5-acetyl-2-thiophenecarboxylic acid can be obtained by hydrolyzing this compound with an acid as described above. Thus, the novel compounds 5-acetyl-2- (α-alkoxyimino) ethylthiophene and 5- (α-alkoxyimino) ethyl-2-thiophenecarboxylic acid according to the present invention are prepared from 2- (α-alkoxyimino) ethylthiophene. It can be easily obtained and is very useful as an intermediate in the organic synthesis compound industry.

As described above, the present invention discloses a novel method of utilizing an oxime, which is conventionally often used as a method for identifying an organic compound, as an industrial raw material, and is a novel compound based on the above findings. 5-acetyl-2- (α
-Alkoxyimino) ethylthiophene and 5- (α-
It is an object to provide an alkoxyimino) ethyl-2-thiophenecarboxylic acid and a method for producing the same.

Means for Solving the Problems The novel 2- (α-alkoxyimino) ethylthiophene derivative according to the present invention has the general formula (I): (In the formula, R represents an alkyl group having 1 to 4 carbon atoms, and Z represents an acetyl group or a carboxyl group.).

In the above general formula (I), R represents an alkyl group having 1 to 4 carbon atoms, and the alkyl group may be linear or branched. Therefore, specific examples of such an alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, and an n group.
-Butyl group, t-butyl group and the like can be mentioned.

Further, in the above general formula (I), Z represents an acetyl group or a carboxyl group, and accordingly, the present invention provides a novel 5-
Acetyl-2- (α-alkoxyimino) ethylthiophene and 5- (α-alkoxyimino) ethyl-2-thiophenecarboxylic acid are provided.

Therefore, specific examples of 5-acetyl-2- (α-alkoxyimino) ethylthiophene according to the present invention include, for example, 5-acetyl-2- (α-methoxyimino) ethylthiophene and 5-acetyl-2- (α-ethoxy). Imino) ethylthiophene, 5-acetyl-2- (α-n-
Propoxyimino) ethylthiophene, 5-acetyl-
2- (α-isopropoxyimino) ethylthiophene,
Examples include 5-acetyl-2- (α-n-butoxyimino) ethylthiophene.

Further, specific examples of the 5- (α-alkoxyimino) ethyl-2-thiophenecarboxylic acid according to the present invention include, for example, 5- (α-methoxyimino) ethyl-2-thiophenecarboxylic acid, 5- (α- Ethoxyimino) ethyl-2
-Thiophenecarboxylic acid, 5- (α-n-propoxyimino) ethyl-2-thiophenecarboxylic acid, 5- (α-
Examples thereof include n-butoxyimino) ethyl-2-thiophenecarboxylic acid.

The 5-acetyl-2- (α-alkoxyimino) ethylthiophene according to the present invention has the general formula (IV) (In the formula, R is the same as the above.) It can be obtained by acetylating the corresponding 2- (α-alkoxyimino) ethylthiophene. 2- (α-Alkoxyimino) ethylthiophene can be obtained by reacting 2-acetylthiophene oxime with an alkylating agent in the presence of a base.

Since 2- (α-alkoxyimino) ethylthiophene represented by the above general formula (IV) is also a novel compound, the production of this compound will be described first.

2-Acetylthiophene oxime is prepared according to the conventional method,
It can be obtained in high yield by oximation of acetylthiophene, for example with hydroxylamine.

O-alkylation of 2-acetylthiophene oxime can be carried out by a conventionally known ordinary O-alkylation method, but in the present invention, as the alkylating agent, dimethylsulfate, diethylsulfate, Dialkyl sulfuric acid such as dipropyl sulfuric acid and the like, and alkyl halides such as methyl iodide, ethyl iodide, isopropyl bromide and n-butyl bromide can be preferably used.

The amount of these alkylating agents used is not particularly limited, but is usually in the range of 0.5 to 2 times mol, preferably 1.0 to 1.2 times mol, relative to the 2-acetylthiophene oxime used. When the amount of the alkylating agent used is too small, the yield of the desired 2- (α-alkoxyimino) ethylthiophene is low, while when too much is used, a particularly advantageous effect cannot be obtained. Is.

The O-alkylation reaction of 2-acetylthiophene oxime is usually carried out in the presence of a base. Such bases include alkali metal and alkaline earth metal hydroxides,
A hydride, a carbonate, a hydrogen carbonate, a metal alkoxide or the like can be preferably used. However, if desired, aliphatic, aromatic and heterocyclic tertiary amines such as triethylamine, dimethylaniline and pyridine can also be used. In particular, when an alkali metal hydroxide, hydride or alkoxide is used, the desired 2- (α-alkoxyimino) ethylthiophene can be obtained in high yield.

The amount of these bases to be used is also not particularly limited, but it is usually in the range of 0.8 to 2 times mol, preferably 1.0 to 1.2 times mol, relative to the 2-acetylthiophene oxime used. Similar to the alkylating agent, when the amount of the base used is too small, the yield of the target 2- (α-alkoxyimino) ethylthiophene is low, while when too much is used, a particularly advantageous effect is obtained. Can't get

The O-alkylation reaction of 2-acetylthiophene oxime is usually performed in a solvent. As a solvent,
The 2-acetylthiophene oxime to be used is dissolved, and as long as it is inactive in the reaction, it is not particularly limited, but preferably, in addition to water, lower aliphatic alcohols such as methanol, ethanol and isopropanol, Acetone, ketones such as methyl ethyl ketone, ethers such as ethyl ether, tetrahydrofuran, dioxane, halogenated hydrocarbons such as dichloroethane, chloroform, carbon tetrachloride and chlorobenzene, aromatic hydrocarbons such as benzene, toluene and xylene, N ,
Mention may be made of acid amides such as N-dimethylformamide and N, N-dimethylacetamide, sulfoxides such as dimethylsulfoxide, and mixtures of two or more thereof. Particularly, N, N-dimethylformamide and an aqueous solution thereof, that is, water-containing N, N-dimethylformamide is preferable from the viewpoint of being able to obtain the desired product in a high yield.

The temperature of the O-alkylation reaction of 2-acetylthiophene oxime is usually in the range of about -10 ° C to about 50 ° C, preferably about 0 ° C to 35 ° C. Particularly preferably, it is in the range of about 5 ° C to about 20 ° C. When the reaction temperature is higher than about 50 ° C, the yield of desired 2- (α-alkoxyimino) ethylthiophene decreases due to side reaction, while when the reaction temperature is lower than about -10 ° C. The reaction speed is too slow for practical use.

After completion of the alkylation reaction of 2-acetylthiophene oxime, the reaction mixture is extracted with, for example, chloroform, washed with water, the chloroform is distilled off, and the residue is further distilled under reduced pressure. , Usually as a liquid,
2- (α-alkoxyimino) ethylthiophene represented by the general formula (IV) can be separated. Further, 2- (α-alkoxyimino) ethylthiophene represented by the general formula (IV) can also be separated by distilling the reaction mixture as it is under reduced pressure.

Next, the production of 5-acetyl-2- (α-alkoxyimino) ethylthiophene according to the present invention will be described.

5-Acetyl-2- (α-alkoxyimino) ethylthiophene is obtained by acetylating 2- (α-alkoxyimino) ethylthiophene obtained as described above with a acetylating agent in the presence of a catalyst. You can get it.

As the acetylating agent, for example, acetic anhydride or acetyl halide, for example, acetyl chloride is suitable. As the catalyst, Lewis acids such as aluminum chloride, zinc chloride and ferric chloride are suitable. When acetic anhydride is used as the acetylating agent, an acid catalyst such as sulfuric acid, polyphosphoric acid or perchloric acid can be used as the catalyst. Particularly, polyphosphoric acid is preferable.

The amount of the acetylating agent to be used is not particularly limited, but is usually 1 to 10 times mol, preferably 1.0 to 5 times the mol of 2- (α-alkoxyimino) ethylthiophene used.
It is in the double molar range.

A solvent does not necessarily have to be used for the acetylation reaction, but a method using a solvent is preferable. Thus, when the reaction is carried out in the presence of a solvent, suitable solvents are, for example, acetic anhydride, dichloromethane, 1,2-dichloroethane, chloroform, and aliphatic halogenated hydrocarbons such as carbon tetrachloride.

The temperature of the above-mentioned acetylation reaction is usually about 40 ° C. to about 120 °
C., preferably about 50.degree. C. to about 110.degree. When the reaction temperature is higher than about 120 ° C, side reactions occur, while when the reaction temperature is lower than about 40 ° C,
This is because the reaction rate is too slow for practical use.

Generally, as is well known, there are two geometric isomers of oxime, a syn-form and an anti-form. Similarly, the above-mentioned 2- (α-alkoxyimino)
Also in ethylthiophene, there are two geometric isomers, a syn-form in which the alkoxy group is on the same side as the thiophene ring and an anti-form in which the alkoxy group is on the opposite side. According to the method described above, a mixture of these syn-forms and anti-forms can be obtained, but for the production of 2- (α-alkoxyimino) ethylthiophene used in the present invention, the mixture of the syn-forms and anti-forms described above is obtained. Can be used. Of course, the syn body and the anti body may be used respectively.

The 5-acetyl-2- (α-alkoxyimino) ethylthiophene obtained as described above is subjected to an oxidative decomposition reaction using a hypohalite in a solvent, that is, a haloform reaction. (Α-Alkoxyimino) ethyl-2-thiophenecarboxylic acid can be obtained.

As the hypohalite, for example, sodium hypochlorite, sodium hypobromite, potassium hypochlorite and the like can be preferably used. These hypohalites are usually used in a range of 2 to 5 times, preferably 3 to 4 times the mol of 5-acetyl-2- (α-alkoxyimino) ethylthiophene. As the solvent, water or a water-soluble organic solvent, for example, a mixed solvent of a lower aliphatic alcohol such as methanol can be used.

The temperature of the haloform reaction is usually about 20 ° C to about 100 ° C.
C., preferably about 40 to 70.degree. This is because when the reaction temperature is higher than about 100 ° C, a side reaction occurs, while when the reaction temperature is lower than about 20 ° C, the reaction rate is practically too slow.

EFFECTS OF THE INVENTION 5-Acetyl-2- (α-alkoxyimino) ethylthiophene and 5- (α-alkoxyimino) ethyl-2-thiophenecarboxylic acid according to the present invention are novel compounds, and are pharmaceuticals, agricultural chemicals, etc. It can be widely used as an intermediate for the production of In addition, these compounds are oxime-formed from 2-acetylthiophene, which is easily available as an industrial raw material, and the resulting oxime is O-.
It can be produced in a high yield through the steps of alkylation and acetylation of the thiophene ring (and acid hydrolysis of this acetyl group).

EXAMPLES The present invention will be specifically described below with reference to Reference Examples and Examples.

Reference Example 1 Synthesis of 2-acetylthiophene oxime 100 g of 2-acetylthiophene (0.79) in a one-volume four-necked flask equipped with a stirrer, a dropping funnel, a thermometer and a condenser.
4 mol), 59.8 g of hydroxylamine hydrochloride, 44.3 g of sodium carbonate, 192 g of methanol and 225 g of water were added, the temperature was raised to the reflux temperature with stirring, and acetic acid was added to this to adjust the pH to 4
And refluxed for 2 hours with stirring. After this, part of the methanol was distilled off, and after cooling, the precipitate formed was filtered off,
This was washed with water and dried, and 110.2 g of white 2-acetylthiophene oxime (mixture of anti form and syn form) (yield
98.5%). Melting point 82-93 ° C.

Reference Example 2 Synthesis of 2- (α-methoxyimino) ethylthiophene N, N-dimethylformamide 141.7 in a 2-volume four-necked flask equipped with a stirrer, a dropping funnel, a thermometer and a condenser.
g, 32.9 g (0.823 mol) of sodium hydroxide and 35.4 g of water were charged.

2-Acetylthiophene oxime 110.2 g (0.782 mol)
214 g of an N, N-dimethylformamide solution in which was dissolved in the above flask was added dropwise to the flask at a temperature of 15 to 20 ° C. over 1 hour, then cooled to 10 ° C., and 108.9 g of 95% dimethyl sulfuric acid was added thereto. (0.821 mol) was added dropwise at a temperature of 10 ° C. for 1 hour. After completion of dropping, the mixture was stirred at the same temperature for 30 minutes.

Then, the reaction mixture was diluted with water and extracted with chloroform. The chloroform extract was washed with water, and then chloroform was distilled off. By distilling the residue under reduced pressure, 100.6 g of 2- (α-methoxyimino) ethylthiophene was obtained as a colorless transparent liquid (70 to 72 ° C./3 mmHg). The yield was 83 based on 2-acetylthiophene oxime.
It was in%.

The data of elemental analysis value, nuclear magnetic resonance absorption spectrum and infrared absorption spectrum of 2- (α-methoxyimino) ethylthiophene and the molecular weight by mass spectrometry are shown below.

Elemental analysis value C H N S measurement value 54.43 5.80 9.00 20.45 calculated value 54.19 5.81 9.03 20.65 NMR (δ ppm, CDCl ₃ ) 2.18-2.30 (s, 3H), 3.92-4.00 (s, 3H), 6.90-7.49
(M, 3H). IR (cm ^-1 ) 2960,2945,2900,2825,1440,1305,1240,1060,1040,896,8
55,710. Molecular Weight 155 Reference Example 3 The same operation as in Reference Example 2 was performed except that the alkylating agent, the base and the reaction solvent shown in Table 1 were used, and the same molar amount was used. 2- (α-shown in Table 1
Alkoxyimino) ethylthiophene was obtained.

In Table 1, 2- (α-ethoxyimino) ethylthiophene obtained with the number 5 and 2- (α obtained with the number 7)
The appearance, boiling point, elemental analysis value, spectral data, and molecular weight by mass spectrometry of -n-butoxyimino) ethylthiophene are shown.

2- (α-Ethoxyimino) ethylthiophene Appearance Colorless transparent liquid Boiling point 77-78 ℃ / 2mmHg Elemental analysis value CHNS measurement value 56.52 6.78 8.32 18.71 measurement value 56.80 6.51 8.28 18.93 NMR (δppm, CDCl ₃ ) 1.2-1.5 (t, 3H), 2.18-2.29 (s, 3H) , 4.05-4.40 (q,
2H), 6.85-7.45 (m, 3H). IR (cm ^-1 ) 2980,2940,2880,1595,1442,1380,1300,1230,1095,1050,
990,910,921,890,855,705. Molecular weight 169 2- (α-n-butoxyimino) ethylthiophene Appearance Colorless transparent liquid Boiling point 94-98 ° C / 3.5mmHg Elemental analysis value C H N S measured value 60.68 7.50 7.31 16.50 Calculated value 60.91 7.61 7.11 16.24 NMR (δppm , CDCl ₃ ) 0.85-1.10 (t, 3H), 1.20−2.00 (m, 4H), 2,20−2.31
(S, 3H), 4.08-4.32 (t2H), 8.9-7.50 (m, 3H). IR (cm ^-1 ) 2970,2950,2880,1600,1440,1380,1300,1240,1080,1040,
1000,920,900,860,710. Molecular weight 197 Example 1 Synthesis of 5-acetyl-2- (α-methoxyimino) ethylthiophene Acetic anhydride 258 g (2.53 mol), polyphosphoric acid 61 g and 2- (α-methoxy) were placed in a three-volume four-necked flask. (Imino)
Charge ethyl thiophene 100.6g (0.649mol), 100 ℃
The mixture was stirred for 9 hours. After the reaction, the mixture was cooled to room temperature, and methanol and water were added to dilute or decompose excess acetic anhydride and polyphosphoric acid. Further, a 20 wt% sodium hydroxide aqueous solution was added to neutralize the mixture, and the mixture was extracted with chloroform.

After the extracted chloroform solution was washed with water, chloroform was distilled off to obtain 114.8 g of crude 5-acetyl-2- (α-methoxyimino) ethylthiophene. This was recrystallized from methanol to give 5-acetyl- as a pale yellow solid.
67.1 g of 2- (α-methoxyimino) ethylthiophene was obtained.

The yield was 52.5% based on 2- (α-methoxyimino) ethylthiophene.

The melting point of 5-acetyl-2- (α-methoxyimino) ethylthiophene, elemental analysis values, spectral data, and molecular weight by mass spectrometry are shown.

Melting point 104-105 ° C Elemental analysis value CHNS measurement value 54.58 5.69 6.98 16.28 Calculated value 54.82 5.58 7.11 16.24 NMR (δ ppm, CDCl ₃ ) 2.20-2.33 (s, 3H), 2.53-2.56 (s, 3H), 3.98 −4.06
(S, 3H), 7.17-7.65 (dd, 2H). IR (cm ^-1 ) 3100,2930,2900,2810,1650,1530,1460,1360,1295,1270,
1050,920,890,590,495. Molecular weight 197 Example 2 Synthesis of 5- (α-methoxyimino) ethyl-2-thiophenecarboxylic acid Crude 5-acetyl-2- (α obtained in Example 1 in a 2-volume four-necked flask. 114.8 g of (methoxyimino) ethylthiophene (corresponding to 0.415 mol in terms of 100% purity) and 116 g of methanol were charged, and the temperature was raised to 70 ° C. with stirring. To this, 1124 g of a 10% sodium hypochlorite aqueous solution was added dropwise at the same temperature over 30 minutes, and the mixture was further stirred for 30 minutes.

After the reaction, the reaction mixture was cooled to room temperature, washed with chloroform to remove unreacted 2- (α-methoxyimino) ethylthiophene, etc., acidified with concentrated hydrochloric acid, and the precipitate was filtered, washed with water and dried. As a white solid, 5- (α-
Methoxyimino) ethyl-2-thiophenecarboxylic acid 8
Obtained 2.6 g.

The yield was 64.0% with respect to 2- (α-methoxyimino) ethylthiophene.

The melting point of 5- (α-methoxyimino) ethyl-2-thiophenecarboxylic acid, elemental analysis value, spectral data, and molecular weight by mass spectrometry are shown.

Melting point 205 to 206 ° C Elemental analysis value CHNS measurement value 48.42 4.43 7.21 15.92 calculated value 48.24 4.52 7.04 16.08 NMR (δ ppm, CDCl ₃ ) 2.19-2.29 (s, 3H), 3.90-3.99 (s, 3H), 7.40 −7.74
(Dd, 2H). IR (cm ^-1 ) 2950,2825,2675,1700,1670,1542,1480,1430,1310,1280,
1060,900,830,750,530. Molecular weight 199 Example 3 Using 2- (α-alkoxyimino) ethylthiophene, an acetylating agent, a catalyst and a solvent shown in Table 2 in the same manner as in Example 1, 5 -Acetyl-2- (α-alkoxyimino) ethylthiophene was obtained.

Further, the 5-acetyl-2- (α
The -alkoxyimino) ethylthiophenes were treated as in Example 2 to give the corresponding 5- (α-alkoxyimino) ethyl-2-thiophenecarboxylic acids, respectively, as shown in Table 2.

About these 5-acetyl-2- (α-alkoxyimino) ethylthiophene and 5- (α-alkoxyimino) ethyl-2-thiophenecarboxylic acid, the appearance, melting point,
The elemental analysis value, the spectrum data, and the molecular weight by mass spectrometry are shown.

5-Acetyl-2- (α-ethoxyimino) ethylthiophene Appearance White solid Melting point 42-49 ° C Elemental analysis value CHNS measurement value 56.60 6.11 6.92 15.10 Calculated value 55.87 6.16 6.64 15.17 NMR (δppm, CDCl ₃ ) 1.22-1.48 (T, 3H), 2.22-2.32 (s, 3H), 2.52-2.56
(S, 3H), 4.1-4.45 (q, 2H), 7.16-7.66 (dd, 2H). IR (cm ^-1 ) 2990,2940,1670,1470,1450,1360,1300,1280,1045,1000,
935,820,600,530. Molecular weight 211 5- (α-Ethoxyimino) ethyl-2-thiophenecarboxylic acid Appearance White solid Melting point 150-164 ° C Elemental analysis value CHNS measurement value 50.92 5.08 6.39 15.22 Calculated value 50.70 5.16 6.57 15.02 NMR (δppm) , CDCl ₃ ) 1.16-1.38 (t, 3H), 2.20-2.29 (s, 3H), 4.03-4.35
(Q, 2H), 7.35−7.72 (2H). IR (cm ^-1 ) 3125,2990,2680,1700,1540,1480,1425,1345,1310,1280,
1120,1000,920,846,760,505.Molecular weight 213 5- (α-n-butoxyimino) ethyl-2-thiophenecarboxylic acid Appearance White solid Melting point 125-135 ° C Elemental analysis CHN S Measured value 54.68 5.99 5.71 13.21 Calculated value 54.77 6.22 5.81 13.28 NMR (δppm, CDCl ₃ ) 0.83−0.99 (t, 3H), 1.16−1.90 (m, 4H), 2.20−2.30
(S, 3H), 4.05-4.30 (t, 2H), 7.36-7.73 (dd, 2H). IR (cm ^-1 ) 2960,2950,2880,1710,1678,1545,1482,1422,1342,1310,
1280,1120,1080,1050,1000,925,830,755.Molecular weight 241

Claims (22)

[Claims] 1. A general formula (In the formula, R represents an alkyl group having 1 to 4 carbon atoms, and Z represents an acetyl group or a carboxyl group.) A 2- (α-alkoxyimino) ethylthiophene derivative. 2. Z is an acetyl group.
Item 2- (α-alkoxyimino) ethylthiophene derivative 3. A 2- (α-alkoxyimino) ethylthiophene derivative according to claim 2, wherein R is a methyl group. 4. A 2- (α-alkoxyimino) ethylthiophene derivative according to claim 2, wherein R is an ethyl group. 5. The 2- (α-alkoxyimino) ethylthiophene derivative according to claim 2, wherein R is an n-butyl group. 6. A 2- (α-alkoxyimino) ethylthiophene derivative according to claim 1, wherein Z is a carboxyl group. 7. A 2- (α-alkoxyimino) ethylthiophene derivative according to claim 6, wherein R is a methyl group. 8. A 2- (α-alkoxyimino) ethylthiophene derivative according to claim 6, wherein R is an ethyl group. 9. The 2- (α-alkoxyimino) ethylthiophene derivative according to claim 6, wherein R is an n-butyl group. 10. General formula (In the formula, R represents an alkyl group having 1 to 4 carbon atoms.) 2- (α-alkoxyimino) ethylthiophene represented by the general formula is acetylated. (In the formula, R is the same as above.) A method for producing 5-acetyl-2- (α-alkoxyimino) ethylthiophene. 11. A method according to claim 10, wherein R is a methyl group.
Item 5-acetyl-2- (α-alkoxyimino)
Method for producing ethylthiophene. 12. A method according to claim 10, wherein R is an ethyl group.
Item 5-acetyl-2- (α-alkoxyimino)
Method for producing ethylthiophene. 13. The method for producing 5-acetyl-2- (α-alkoxyimino) ethylthiophene according to claim 10, wherein R is an n-butyl group. 14. Using acetic anhydride as an acetylating agent,
11. 5-Acetyl- according to claim 10, wherein 2- (α-alkoxyimino) ethylthiophene is acetylated.
A method for producing 2- (α-alkoxyimino) ethylthiophene. 15. The method for producing 5-acetyl-2- (α-alkoxyimino) ethylthiophene according to claim 14, wherein 2- (α-alkoxyimino) ethylthiophene is acetylated in the presence of polyphosphoric acid. 16. The method according to claim 10, wherein 2- (α-alkoxyimino) ethylthiophene is acetylated by using acetyl halide as an acetylating agent.
A process for producing acetyl-2- (α-alkoxyimino) ethylthiophene. 17. The 5-acetyl-2- (α) according to claim 16, wherein the acetyl halide is acetyl chloride.
-Alkoxyimino) ethylthiophene production method. 18. A general formula (In the formula, R represents an alkyl group having 1 to 4 carbon atoms.) 5-acetyl-2- (α-alkoxyimino) ethylthiophene represented by the general formula characterized by reacting with hypohalite (In the formula, R represents an alkyl group having 1 to 4 carbon atoms.) A method for producing 5- (α-alkoxyimino) ethyl-2-thiophenecarboxylic acid. 19. A method according to claim 18, wherein R is a methyl group.
5. A method for producing 5- (α-alkoxyimino) ethyl-2-thiophenecarboxylic acid according to the above item. 20. A method according to claim 18, wherein R is an ethyl group.
5. A method for producing 5- (α-alkoxyimino) ethyl-2-thiophenecarboxylic acid according to the above item. 21. 5- (α-Alkoxyimino) ethyl-2 according to claim 18, wherein R is an n-butyl group.
-Method for producing thiophenecarboxylic acid. 22. The method for producing 5- (α-alkoxyimino) ethyl-2-thiophenecarboxylic acid according to claim 18, wherein the hypohalite is sodium hypochlorite.