4-HYDROXY-6-METHOXYQUINOLINE-3-CARBOXYLIC ACID

4-HYDROXY-6-METHOXYQUINOLINE-3-CARBOXYLIC ACID Property

Melting point:

278-279 °C (decomp)

Boiling point:

418.6±45.0 °C(Predicted)

Density 

1.444±0.06 g/cm3(Predicted)

storage temp. 

Inert atmosphere,Room Temperature

form 

solid

pka

0.74±0.30(Predicted)

Appearance

Off-white to light yellow Solid

CAS DataBase Reference

28027-16-9(CAS DataBase Reference)

Safety

HS Code 

2933499090

Hazard and Precautionary Statements (GHS)

Symbol(GHS)

Signal word

Warning

Hazard statements

H302Harmful if swallowed

H315Causes skin irritation

H319Causes serious eye irritation

H335May cause respiratory irritation

Precautionary statements

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

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

4-HYDROXY-6-METHOXYQUINOLINE-3-CARBOXYLIC ACID Chemical Properties,Usage,Production

Synthesis

General procedure for the synthesis of 4-hydroxy-6-methoxyquinoline-3-carboxylic acid from ethyl 4-hydroxy-6-methoxyquinoline-3-carboxylate: ethyl 4-hydroxy-6-methoxyquinoline-3-carboxylate (17.8 g, 72 mmol) was suspended in 170 mL of aqueous 2 N sodium hydroxide solution, heated to 90 °C, and the reaction was maintained for 1.5 h. The mixture was cooled to room temperature and slowly poured into ice water. Upon completion of the reaction, the mixture was cooled to room temperature, slowly poured into ice water and the pH was adjusted to 5 with 2 N hydrochloric acid.The precipitated solid was collected by filtration, washed with cold water and dried to give 4-hydroxy-6-methoxyquinoline-3-carboxylic acid (15.8 g, 72 mmol, 99% yield). The product was characterized by 1H-NMR (DMSO-d6): δ= 3.91 (s, 3H), 7.53 (dd, 1H), 7.64 (d, 1H), 7.82 (d, 1H), 8.80 (d, 1H), 13.63 (bs, 1H), 15.55 (s, 1H).Results of LC-MS analysis: retention time (Rt) = 1.20 min; Mass spectrum (MS): m/z = 220 [M+H]+.

References

[1] Tetrahedron Letters, 2017, vol. 58, # 8, p. 794 - 796
[2] Journal of the American Chemical Society, 1946, vol. 68, p. 1204,1206
[3] Organic Syntheses, 1955, vol. Coll. Vol. III, p. 272
[4] Journal of the American Chemical Society, 1947, vol. 69, p. 1659,1660
[5] Journal of the Chemical Society, 1946, p. 1033,1035