Hydrochloric Acid → 5-Bromoquinazoline-2,4(1H,3H)-dione

HRID 2036771Notes

Reaction equation

[NH2:1][C:2]1[CH:10]=[CH:9][CH:8]=[C:7]([Br:11])[C:3]=1[C:4](O)=[O:5].[O-:12][C:13]#[N:14].[Na+].[OH-].[Na+].Cl>O.C(O)(=O)C>[Br:11][C:7]1[CH:8]=[CH:9][CH:10]=[C:2]2[C:3]=1[C:4](=[O:5])[NH:14][C:13](=[O:12])[NH:1]2

Participants

Conditions

Temperature: 35 °C

Procedure

2-Amino-6-bromobenzoic acid (2.97 g, 13.7 mmol) was suspended in a mixture of water (100 mL) and acetic acid (1.5 mL) at 35° C. then a suspension of sodium cyanate (2.23 g, 34.4 mmol) in 10 mL of water was added slowly to the mixture. Upon completion of addition, the resulting mixture was stirred at 35° C. for 30 minutes and then sodium hydroxide (24.7 g, 619 mmol) pellets were slowly added to the mixture to yield a thick precipitate. The mixture was cooled to 5° C. in an ice bath and the pH of the suspension was adjusted to 4 using concentrated HCl. Once at the prescribed pH, the suspension was filtered and the solid was washed with water and dried under vacuum while heating at 100° C. to give 5-bromo-1H-quinazoline-2,4-dione (1.91 g) as a brown solid. 1H NMR (400 MHz, DMSO-d6) δ ppm 11.30 (1 H, br. s.), 11.26 (1H, br. s.), 7.43-7.48 (1H, m), 7.40 (1H, dd, J=7.78, 1.25 Hz), 7.16 (1H, dd, J=7.91, 1.13 Hz).

Workup

additionwas added slowly to the mixture
additionUpon completion of addition
customto yield a thick precipitate
temperatureThe mixture was cooled to 5° C. in an ice bath
filtrationOnce at the prescribed pH, the suspension was filtered
washthe solid was washed with water
customdried under vacuum
temperaturewhile heating at 100° C.

Sources & evidence

ORD record: ord-a8c79fbca67247529f593aa70ded229a
Source dataset: uspto-grants-2013_11
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08575184B2

Reaction notes

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