3-Bromo-7-chloropyrazolo[1,5-a]pyrimidine

3-Bromo-7-chloropyrazolo[1,5-a]pyrimidine Property

Density 

2.03

storage temp. 

under inert gas (nitrogen or Argon) at 2–8 °C

pka

-1.91±0.40(Predicted)

Appearance

Light yellow to green yellow Solid

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

P264Wash hands thoroughly after handling.

P264Wash skin thouroughly after handling.

P270Do not eat, drink or smoke when using this product.

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

P301+P312IF SWALLOWED: call a POISON CENTER or doctor/physician IF you feel unwell.

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.

P321Specific treatment (see … on this label).

P330Rinse mouth.

P332+P313IF SKIN irritation occurs: Get medical advice/attention.

P362Take off contaminated clothing and wash before reuse.

P501Dispose of contents/container to..…

3-Bromo-7-chloropyrazolo[1,5-a]pyrimidine Chemical Properties,Usage,Production

Synthesis

The general procedure for the synthesis of 3-bromo-7-chloropyrazolo[1,5-a]pyrimidines using 7-chloropyrazolo[1,5-a]pyrimidines as starting material was as follows: a solution of crude 7-chloropyrazolo[1,5-a]pyrimidines (44.2 g, 289 mmol) was cooled down to 0 °C in dichloromethane (289 mL) in the conditions of an ice bath. N-bromosuccinimide (51.4 g, 289 mmol) was slowly added, followed by stirring the reaction mixture for 16 hours at room temperature. After completion of the reaction, the dark orange reaction solution was diluted with dichloromethane (200 mL) and washed sequentially with 10% potassium carbonate solution (3 x 150 mL) and brine (100 mL). The organic phase was separated, dried over anhydrous sodium sulfate and concentrated under reduced pressure to give a dark orange solid. The solid was ground with methanol to afford the target product 3-bromo-7-chloropyrazolo[1,5-a]pyrimidine (50.9 g, 76% yield) as a yellow solid. The product was analyzed by HPLC with a purity of 96%; 1H NMR (250 MHz, CDCl3) δ 8.49 (d, J = 5.2 Hz, 1H), 8.25 (s, 1H), 7.07 (d, J = 5.2 Hz, 1H); 13C NMR (62.9 MHz, DMSO) δ 150.4, 145.9, 144.7, 138.5. 109.5, 84.7.

References

[1] ChemMedChem, 2014, vol. 9, # 11, p. 2516 - 2527
[2] Patent: WO2007/17678, 2007, A1. Location in patent: Page/Page column 44-45