Hydrogen Bromide → 1-(6,6-Dibromo-7-oxo-4,5,6,7-tetrahydro-2-benzothiazolyl)-3-ethyl-urea

HRID 9107Notes

Reaction equation

[O:1]=[C:2]1[C:10]2[S:9][C:8]([NH:11][C:12]([NH:14][CH2:15][CH3:16])=[O:13])=[N:7][C:6]=2[CH2:5][CH2:4][CH2:3]1.[BrH:17].[Br:18]Br>CC(O)=O>[Br:17][C:3]1([Br:18])[CH2:4][CH2:5][C:6]2[N:7]=[C:8]([NH:11][C:12]([NH:14][CH2:15][CH3:16])=[O:13])[S:9][C:10]=2[C:2]1=[O:1]

Participants

Conditions

Temperature: 45 °C

Procedure

A solution of 1-(7-oxo-4,5,6,7-tetrahydro-2-benzothiazolyl)-3-ethyl-urea 4 (5.00 g, 20.9 mmol), 48% HBr (aq) (1.20 mL, 2.09 mmol, 0.1 eq) and AcOH (451 mL) was treated dropwise with a solution of Br2 (2.21 mL, 42.8 mmol, 2.05 eq) in AcOH (5 mL) with stirring. The reaction mixture was heated at about 45° C. with stirring for about 16 hours with a condensor on top of the reaction flask. An orange colored suspension was obtained. The solid was filtered off and washed with Et2O (20 mL), toluene (50 mL) and Et2O (3×30 mL). After drying under vacuum, 7.78 g (94%) of compound 5 was obtained. 1H NMR (DMSO) δ 11.35 (br s, 1H, NH), 6.78 (br s, 1H, NH), 3.18 (m, 2H, CH2), 3.12 (t, 2H, J=5.6 Hz, CH2), 2.91 (t, 2H, J=5.6 Hz, CH2), 1.08 (t, 3H, J=7.2 Hz, CH3); LC/MS 396 (MH+); RP-HPLC RT 3.04 minutes.

Workup

stirringwith stirring for about 16 hours with a condensor on top of the reaction flask
customAn orange colored suspension was obtained
filtrationThe solid was filtered off
washwashed with Et2O (20 mL), toluene (50 mL) and Et2O (3×30 mL)
customAfter drying under vacuum

Sources & evidence

ORD record: ord-514fddbecd104874be43c28786f03d53
Source dataset: uspto-grants-2006_08
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US07091227B2

Reaction notes

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