Diethyl Ether → 1-(7-Oxo-4,5,6,7-tetrahydro-2-benzothiazolyl)-3-ethyl-urea

HRID 9106

Reaction equation

[NH2:1][C:2]1[S:3][C:4]2[C:10](=[O:11])[CH2:9][CH2:8][CH2:7][C:5]=2[N:6]=1.C(N(CC)CC)C.[CH2:19]([N:21]=[C:22]=[O:23])[CH3:20].CCOCC>CN(C=O)C>[O:11]=[C:10]1[C:4]2[S:3][C:2]([NH:1][C:22]([NH:21][CH2:19][CH3:20])=[O:23])=[N:6][C:5]=2[CH2:7][CH2:8][CH2:9]1

Participants

Conditions

Temperature: 90 °C

Procedure

A solution of 2-amino-7-oxo-4,5,6,7-tetrahydro-benzothiazole 3 (11.56 g, 68.7 mmol) in anhydrous DMF (200 mL) was treated with triethylamine (19.2 mL, 137 mmol, 2.0 eq) and ethyl isocyanate (10.9 nL, 137 mmol, 2.0 eq). The reaction mixture was heated at about 90° C. with stirring for about 3 hours. The DMF solvent was distilled off under reduced pressure. A sticky brown residue was obtained. Treatment with Et2O (100 mL) gave a precipitate, which was filtered off and washed with more Et2O (50 mL). The light brown colored solid was dried under vacuum to give 13.97 g (85%) of 4. The material was used in the following synthesis without further purification. 1H NMR (DMSO) δ 10.95 (br s, 1H, NH), 6.66 (br s, 1H, NH), 3.16 (p, 2H, J=7.2 Hz, CH2), 2.79 (t, 2H, J=6.1 Hz, CH2), 2.45 (t, 2H, J=6.5 Hz, CH2), 2.05 (p, 2H, J=6.4 Hz, CH2), 1.07 (t, 3H, J=7.2 Hz, CH3); LC/MS 240 (MH+); RP-HPLC RT 2.27 minutes.

Workup

distillationThe DMF solvent was distilled off under reduced pressure
customA sticky brown residue was obtained
filtrationwas filtered off
washwashed with more Et2O (50 mL)
customThe light brown colored solid was dried under vacuum

Sources & evidence

ORD record: ord-0f07a300f177487084962573f64fed09
Source dataset: uspto-grants-2006_08
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US07091227B2

Linked notes

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