3-Methyl-2-furoic acid

3-Methyl-2-furoic acid Property

Melting point:

134-138 °C

Boiling point:

174.21°C (rough estimate)

Density 

1.2048 (rough estimate)

refractive index 

1.4189 (estimate)

storage temp. 

2-8°C

solubility 

soluble in Methanol

form 

powder to crystal

pka

3.45±0.20(Predicted)

color 

White to Almost white

BRN 

116183

CAS DataBase Reference

4412-96-8(CAS DataBase Reference)

NIST Chemistry Reference

3-Methyl-2-furoic acid(4412-96-8)

Safety

Hazard Codes 

Xn,Xi

Risk Statements 

36/37/38-20/21/22

Safety Statements 

36/37/39-26-36

WGK Germany 

3

HS Code 

29321900

Hazard and Precautionary Statements (GHS)

Symbol(GHS)

Signal word

Warning

Hazard statements

H315Causes skin irritation

H319Causes serious eye irritation

H335May cause respiratory irritation

Precautionary statements

P261Avoid breathing dust/fume/gas/mist/vapours/spray.

P264Wash hands thoroughly after handling.

P264Wash skin thouroughly after handling.

P271Use only outdoors or in a well-ventilated area.

P280Wear protective gloves/protective clothing/eye protection/face protection.

P302+P352IF ON SKIN: wash with plenty of soap and water.

P305+P351+P338IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continuerinsing.

3-Methyl-2-furoic acid Chemical Properties,Usage,Production

Chemical Properties

white to beige powder

Uses

Used in a palladium-catalyzed cross-coupling between heteroaryl carboxylic acids and aryl bromides leading to arylated heterocycles. Also used in a palladium-catalyzed asymmetric hydrogenation.

Uses

3-Methyl-2-furoic acid can be used in a palladium-catalyzed cross-coupling between heteroaryl carboxylic acids and aryl bromides leading to arylated heterocycles.1 Also used in a palladium-catalyzed asymmetric hydrogenation.

Definition

ChEBI: 3-Methyl-2-furoic acid is a furoic acid.

Synthesis

The general procedure for the synthesis of 3-methyl-2-furoic acid from 3-methyl-2-furan methyl ester was as follows: 3-methyl-2-furoic acid methyl ester (2.0 g, 14.3 mmol) was mixed with 30% aqueous sodium hydroxide solution (3.8 mL, 28.5 mmol) and methanol (3.6 mL, 88.8 mmol) and the reaction was carried out under refluxing conditions for 3.5 hours. After completion of the reaction, the solvent was removed by rotary evaporation. The crude product was dissolved in water (10 mL) and the pH was adjusted with concentrated hydrochloric acid to 1. Subsequently, extraction was carried out with ether (4 x 3 mL), the organic phases were combined and dried with anhydrous magnesium sulfate. After filtration, the filtrate was concentrated to dryness to give 3-methyl-2-furoic acid (1.7 g, 13.6 mmol, 95% yield). The melting point of the product was 135 °C (ether). 1H NMR (400 MHz, CDCl3, δ, ppm): 2.40 (3H, s, CH3), 6.41 (1H, d, J4,5 = 1.6 Hz, H4), 7.52 (1H, d, J5,4 = 1.6 Hz, H5). 13C NMR (100 MHz, CDCl3, δ, ppm): 170.2 (COO), 150.1 (C5), 139.9 (C2), 125.3 (C3), 112.0 (C4), 13.3 (Me). IR (membrane, ν, cm-1): 1102 (st.CO), 1136 (st.CO), 1189 (st.CO), 1488 (def.CH), 1599 (st.C=C Ar.), 1670 (st.C=O), 2200-3200 (st.OH). MS (EI, m/z, %): 126.03 (M+, 100); 127.03 (7); 109.03 (M+-OH, 20); 81.03 (40, M+-CHO2). Elemental Analysis (EA). Calculated value C6H6O3: C (57.14), H (4.80). Measured value: C (57.11), H (4.83).

References

[1] Tetrahedron, 2012, vol. 68, # 48, p. 9982 - 9998,17
[2] Tetrahedron, 2012, vol. 68, # 48, p. 9982 - 9998
[3] Patent: US5157134, 1992, A
[4] Patent: US6642237, 2003, B1. Location in patent: Page/Page column 174-175
[5] Journal of Photochemistry and Photobiology A: Chemistry, 2017, vol. 349, p. 7 - 17