反応 #9202

反応方程式

Et2O

2-amino-7-oxo-4,5,6,7-tetrahydro-benzothiazole

2-Amino-7-oxo-4, 5, 6, 7-tetrahydro-benzothiazole

triethylamine

ethyl isocyanate

→

4

収率 85.0%

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

収率 85.0%

溶媒

DMF

反応条件

後処理

1. 1
   workup.DISTILLATIONThe DMF solvent was distilled off under reduced pressure
2. 2
   その他A sticky brown residue was obtained
3. 3
   ろ過was filtered off
4. 4
   洗浄washed with more Et2O (50 mL)
5. 5
   その他The light brown colored solid was dried under vacuum

実験手順

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.

出典