Reaction #1178467

Reaction equation

Me2S

N-(5-tert-butyl-isoxazol-3-yl)-N′-(4-{7-[3-(4-ethyl-piperazin-1-yl)-3-oxo-propyl]imidazo[2,1-b][1,3]benzothiazol-2-yl}phenyl)urea

→

N-(5-tert-butyl-isoxazol-3-yl)-N′-(4-{7-[3-(4-ethyl-piperazin-1-yl)propyl]imidazo[2,1-b][1,3]benzothiazol-2-yl}phenyl)urea

Solvents

THF

THF

Conditions

Workup

1. 1
   TemperatureThe mixture was heated
2. 2
   Temperatureto reflux for 4 hours
3. 3
   OtherThe reaction was quenched by dropwise addition of 10% HCl solution
4. 4
   Extractionwas extracted with dichloromethane
5. 5
   DryingThe combined organic extracts were dried over MgSO4
6. 6
   Concentrationconcentrated
7. 7
   OtherThe crude product was purified by Flash chromatography with silica gel using a 30-100% hexane/ethyl acetate gradient
8. 8
   OtherThe appropriate fractions were collected
9. 9
   Concentrationconcentrated

Procedure

To a suspension of N-(5-tert-butyl-isoxazol-3-yl)-N′-(4-{7-[3-(4-ethyl-piperazin-1-yl)-3-oxo-propyl]imidazo[2,1-b][1,3]benzothiazol-2-yl}phenyl)urea from Example 12A (0.17 g, 0.28 mmol) in THF (10 mL) at room temperature was added 2.0 M solution of BH3/Me2S in THF (1 mL). The mixture was heated to reflux for 4 hours. The reaction was quenched by dropwise addition of 10% HCl solution and stirred at room temperature for 15 min. The mixture was basified with saturated NaHCO3 solution and was extracted with dichloromethane. The combined organic extracts were dried over MgSO4 and concentrated. The crude product was purified by Flash chromatography with silica gel using a 30-100% hexane/ethyl acetate gradient followed by a 0-20% methanol/ethyl acetate gradient. The appropriate fractions were collected, combined, and concentrated to give free base, N-(5-tert-butyl-isoxazol-3-yl)-N′-(4-{7-[3-(4-ethyl-piperazin-1-yl)propyl]imidazo[2,1-b][1,3]benzothiazol-2-yl}phenyl)urea. The free base was dissolved in dichloromethane (about 1 mL) and methanol (a few drops). To this solution was added dropwise a 1.0 M solution of HCl/ether (1.3 equivalents) and a precipitate was formed. After evaporation of the solvents, the residue was taken up in ether, filtered, and washed with ether to give the product as a white solid (0.011 g, 6%). 1H NMR (DMSO-d6) δ 9.6 (s, 1H), 9.07 (s, 1H), 8.69 (s, 1H), 7.92 (m, 2H), 7.78 (d, 2H), 7.54 (d, 2H), 7.48 (d, 1H), 6.53 (s, 1H), 3.50 (4H, overlapping with solvent), 3.22 (m, 6H), 2.75 (m, 4H), 2.10 (m, 2H), 1.30 (s, 9H), 1.24 (t, 3H); LC-MS: ESI 586 (M+H)+.

Source