4-Bromophthalazin-1(2H)-one

4-Bromophthalazin-1(2H)-one Property

Melting point:

273 °C

Density 

1.82±0.1 g/cm3(Predicted)

storage temp. 

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

solubility 

DMSO (Slightly), Methanol (Slightly, Heated, Sonicated)

pka

10.58±0.40(Predicted)

form 

Solid

color 

White to Off-White

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.

4-Bromophthalazin-1(2H)-one Chemical Properties,Usage,Production

Uses

4-Bromo-1(2H)-phthalazinone has been used in the synthesis of Phthalazinone Pyrazoles as Potent, Selective, and Orally Bioavailable Inhibitors of Aurora-A Kinase; novel proteasome inhibitors based on phthalazinone scaffold

Synthesis

The general procedure for the synthesis of 4-bromo-1(2H)-phthalazinone from phthalodicarbohydrazide was as follows: 2,3-dihydro-1,4-diazanaphthalenedione (12.5 g, 78 mmol) was suspended in 1,2-dichloroethane (DCE, 200 ml) and phosphorus pentabromide (50.0 g, 116 mmol) was added. The reaction mixture was heated to reflux for 24 hours. Subsequently, phosphorus pentabromide (20.0 g, 70 mmol) was added and heating to reflux was continued for 24 hours. Upon completion of the reaction, the mixture was cooled to room temperature and slowly poured into ice water. The precipitate was collected by filtration and washed with water to give a crude mixture of mono- and dibrominated products (22.8 g). The crude product was suspended in acetic acid (HOAc, 230.0 mL) and the reaction was heated to 120 °C for 2 hours. At the end of the reaction, it was cooled to room temperature, poured into ice water and filtered to obtain a precipitate. The solid was washed with water and dried to give the final 4-bromo-1(2H)-phthalazinone (10.4 g, 60% yield) as a white solid. The product was characterized by 1H-NMR (400 MHz, D6-DMSO): δ 12.95 (1H, s), 8.25 (1H, dd), 8.03 (1H, ddd), 7.96-7.90 (2H, m); the mass spectrum (ESI+) showed the molecular ion peaks (M + H)+ of 225 and 227.

References

[1] Chemistry - A European Journal, 2016, vol. 22, # 35, p. 12363 - 12370
[2] Patent: US2007/219195, 2007, A1. Location in patent: Page/Page column 39
[3] Journal of Medicinal Chemistry, 2011, vol. 54, # 1, p. 312 - 319
[4] Patent: US4898872, 1990, A
[5] Bioorganic and Medicinal Chemistry Letters, 2016, vol. 26, # 12, p. 2801 - 2805