5-Methyl-2-thiophenecarboxylic acid Chemical Properties

Melting point:

135-138 °C(lit.)

Boiling point:

229.75°C (rough estimate)

Density 

1.365 (estimate)

refractive index 

1.5300 (estimate)

storage temp. 

2-8°C(protect from light)

form 

Liquid

pka

3.71±0.10(Predicted)

color 

Clear

BRN 

113857

InChI

InChI=1S/C6H6O2S/c1-4-2-3-5(9-4)6(7)8/h2-3H,1H3,(H,7,8)

InChIKey

VCNGNQLPFHVODE-UHFFFAOYSA-N

SMILES

C1(C(O)=O)SC(C)=CC=1

CAS DataBase Reference

1918-79-2(CAS DataBase Reference)

NIST Chemistry Reference

5-Methyl-2-thiophenecarboxylic acid (keto form)(1918-79-2)

Safety Information

Hazard Codes 

Xi

Risk Statements 

36/37/38

Safety Statements 

22-24/25

WGK Germany 

3

HazardClass 

IRRITANT

HS Code 

29309090

MSDS

• Language:English Provider:5-Methyl-2-thiophenecarboxylic acid
• Language:English Provider:SigmaAldrich
• Language:English Provider:ACROS
• Language:English Provider:ALFA

5-Methyl-2-thiophenecarboxylic acid Usage And Synthesis

Chemical Properties

BEIGE CRYSTALLINE POWDER

Definition

ChEBI: 5-Methyl-2-thiophenecarboxylic acid is a thiophenecarboxylic acid.

Synthesis Reference(s)

Tetrahedron Letters, 15, p. 2373, 1974 DOI: 10.1016/S0040-4039(01)92259-2

Synthesis

GENERAL PROCEDURE: The general procedure for the synthesis of 5-methyl-2-thiophenecarboxylic acid from 2-acetyl-5-methylthiophene was as follows: Oxone (2 eq.) and trifluoroacetic acid (TFA, 2 eq.) were added to a solution of 2-acetyl-5-methylthiophene (100 mg, 1 eq.) in dioxane (5 mL). The reaction mixture was heated to reflux for 10 hours and subsequently cooled to room temperature. Water (10 mL) was added and the mixture was extracted with ethyl acetate (EtOAc, 2 x 20 mL). The organic layers were combined and washed with saturated sodium bicarbonate (NaHCO3) solution. The sodium bicarbonate solution and the aqueous layer were poured onto crushed ice and acidified with 2 M hydrochloric acid (HCl), at which point a colorless solid precipitated. The precipitate was collected by filtration, dried under vacuum and purified by column chromatography (silica gel; ethyl acetate-hexane, 1:9) to give 5-methyl-2-thiophenecarboxylic acid as a white crystalline solid. Yield: 0.096 g (95% based on 2-acetyl-5-methylthiophene); melting point: 122-123 °C.

References

[1] Synthesis (Germany), 2015, vol. 47, # 20, p. 3161 - 3168
[2] Journal of the American Chemical Society, 1947, vol. 69, p. 3096
[3] Recueil des Travaux Chimiques des Pays-Bas, 1949, vol. 68, p. 5,29

5-Methyl-2-thiophenecarboxylic acid(1918-79-2)Related Product Information

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• 5-METHYL-2-NITROANILINE
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• 5-METHYL-2-THIOPHENESULFONYL CHLORIDE