(R)-1,4-Benzodioxane-2-carboxylic acid

(R)-1,4-Benzodioxane-2-carboxylic acid Property

Melting point:

96-99 °C

Boiling point:

347.2±41.0 °C(Predicted)

alpha 

83 º (c=1.5% in chloroform)

Density 

1.379±0.06 g/cm3(Predicted)

storage temp. 

2-8°C

pka

2.69±0.20(Predicted)

form 

solid

color 

Pale yellow

optical activity

[α]20/D +83±2°, c = 1.5% in chloroform

BRN 

5742837

InChIKey

HMBHAQMOBKLWRX-MRVPVSSYSA-N

CAS DataBase Reference

70918-53-5(CAS DataBase Reference)

Safety

Hazard Codes 

Xi

Risk Statements 

36/37/38

Safety Statements 

26-36

WGK Germany 

3

HS Code 

2932990090

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.

(R)-1,4-Benzodioxane-2-carboxylic acid Chemical Properties,Usage,Production

Chemical Properties

White crystalline powder

Uses

(R)-1,4-Benzodioxane-2-carboxylic acid is a chiral synthon mostly used in the preparation of doxazosin mesylate, a drug treating benign prostatic hyperplasia.

Synthesis

General procedure for the synthesis of 4-benzodioxane-2-carboxylic acid from (2,3-dihydrobenzo[b][1,4]dioxohexen-2-yl)methanol: Accurately weigh (2,3-dihydrobenzo[b][1,4]dioxohexen-2-yl)methanol, and dissolve it in 0.3 N aqueous KOH (1.3 equiv). Potassium permanganate (KMnO4, 2.0 eq.) was slowly added under ice bath conditions at 0 °C. The reaction mixture was first stirred at low temperature for about 10 minutes, then brought to room temperature and continued to stir overnight. Upon completion of the reaction, the organic phase was extracted with dichloromethane, the organic phase was washed with water sequentially, dried over anhydrous sodium sulfate, and concentrated under reduced pressure to give a white solid, i.e., the crude product of 4-benzodioxane-2-carboxylic acid. The crude product was purified by silica gel fast column chromatography, and the final pure product was obtained in 92.5% yield.

References

[1] Patent: CN105985328, 2016, A. Location in patent: Paragraph 0063; 0071; 0072