5-(METHOXYCARBONYL)THIOPHENE-2-CARBOXYLIC ACID Chemical Properties

Melting point:

187-190℃

Boiling point:

365.2±27.0 °C(Predicted)

Density 

1.439±0.06 g/cm3(Predicted)

storage temp. 

2-8°C(protect from light)

pka

3.04±0.10(Predicted)

Appearance

White to yellow Solid

Safety Information

Risk Statements 

20/21/22

Safety Statements 

3/9-24/25-36/37

HazardClass 

IRRITANT

HS Code 

29349990

5-(METHOXYCARBONYL)THIOPHENE-2-CARBOXYLIC ACID Usage And Synthesis

Chemical Properties

White solid

Synthesis

The general procedure for the synthesis of methyl 5-carboxylic acid-2-thiophenecarboxylate from dimethyl thiophene-2,5-dicarboxylate is as follows: to a mildly refluxed solution of dimethyl thiophene-2,5-dicarboxylate (0.430 g, 2.15 mmol) in dioxane/methanol (1:2, 1.5 ml) was added an aqueous sodium hydroxide solution (0.086 g, 2.15 mmol, dissolved in 0.5 ml of water). The reaction mixture was kept under stirring for 5 hours and subsequently cooled to room temperature. After adjusting the pH of the reaction solution to 2 with 1N hydrochloric acid, it was extracted with ethyl acetate (3 x 30 ml). The organic phases were combined, washed with brine (1 x 5 ml), dried over anhydrous magnesium sulfate and concentrated under reduced pressure to afford monomethyl thiophene-2,5-dicarboxylate as a white solid (0.342 g, 86% yield). The product was characterized by 1H NMR (CD3OD): δH 7.72-7.73 (d, 1H), 7.69-7.70 (d, 1H), 3.87 (s, 3H).

Structure and conformation

Thiophene-2,5-dicarboxylic acid monomethyl ester (TDCEM) has been shown to form dimers in solution. The crystal structure of TDCEM has been determined and found to be centrosymmetric with hydrogen bonds between the carbonyl oxygen atoms and the methyl groups on either side, as well as dihedral angles for the two methyl groups.

References

[1] Chemistry - A European Journal, 2016, vol. 22, # 33, p. 11785 - 11794
[2] Patent: US2004/2524, 2004, A1
[3] Patent: WO2004/817, 2003, A2. Location in patent: Page 99
[4] Patent: US2680731, 1950,

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