Pyrazolo[1,5-a]pyrimidine-5,7(4H,6H)-dione

Pyrazolo[1,5-a]pyrimidine-5,7(4H,6H)-dione Property

Melting point:

239-240 °C (decomp)

Boiling point:

290.6±40.0 °C(Predicted)

Density 

1.74±0.1 g/cm3(Predicted)

storage temp. 

2-8°C

pka

4.50±1.00(Predicted)

Appearance

Off-white to light yellow Solid

Safety

HS Code 

2933998090

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.

Pyrazolo[1,5-a]pyrimidine-5,7(4H,6H)-dione Chemical Properties,Usage,Production

Synthesis

Step A - Synthesis of pyrazolo[1,5-a]pyrimidine-5,7-diol (Int-9a): to 1H-pyrazol-3-amine (12.3 g, 148.0 mmol) in 50 mL of deionized water was added diethyl malonate (25.0 mL, 164.7 mmol), followed by the addition of an ethanolic solution of 21 wt% NaOEt (110 mL. 294.6 mmol) and additional ethanol (50 mL). The reaction mixture was heated at 80 °C for 16 h under argon protection. After completion of the reaction, it was cooled to room temperature. The reaction mixture was concentrated to near dryness under reduced pressure and 500 mL of water was added. Dissolution of the solid was promoted by vigorous stirring and the pH was subsequently adjusted to ~2 with hydrochloric acid, at which point a precipitate was generated. The precipitate was collected by vacuum filtration and dried to give pyrazolo[1,5-a]pyrimidine-5,7-diol (Int-9a) as a brown solid (17.13 g, 113.4 mmol, 77% yield).

References

[1] Patent: WO2011/2887, 2011, A1. Location in patent: Page/Page column 86
[2] Patent: WO2012/27234, 2012, A1. Location in patent: Page/Page column 39; 40
[3] Patent: US2011/294781, 2011, A1. Location in patent: Page/Page column 20
[4] Patent: WO2012/27240, 2012, A1. Location in patent: Page/Page column 47
[5] Patent: WO2012/47569, 2012, A1. Location in patent: Page/Page column 41