[Synthesis]
1. N,N-Dimethylaniline (33.4 g, 276 mmol, 1.0 eq.) was slowly added dropwise to a solution of 2,4(1H,3H)-quinazolinedione (50 g, 276 mmol, 1.0 eq.) dissolved in phosphorus oxychloride (POCl3, 300 mL). The reaction mixture was heated to reflux for 3 hours. After cooling to room temperature, the solution was slowly poured into ice water, the precipitate was collected by filtration and washed with cold water. The resulting solid was dissolved in ethyl acetate (EtOAc) and the organic layer was washed sequentially with water and saturated saline. The organic phase was dried over anhydrous sodium sulfate (Na2SO4), filtered and concentrated under reduced pressure, and the residue was washed with petroleum ether to give 2,4-dichloroquinazoline (20 g, 34% yield).
2. A suspension of THF (520 mL) of sodium hydride (NaH, 6 g, 156 mmol, 1.3 eq.) was slowly added dropwise to ethyl acetoacetate (31.2 g, 240 mmol, 2.0 eq.) at 0 °C. The reaction mixture was stirred at 0 °C for 1 h. After removing THF under reduced pressure, a solution of 2,4-dichloroquinazoline (24 g, 120 mmol, 1.0 eq.) in toluene (350 mL) was added and the reaction mixture was heated to reflux for 30 min. After toluene was removed under reduced pressure, ammonia (NH4OH, 320 mL) was added. After stirring for 20 minutes, the mixture was concentrated to remove the ammonia. Ethyl acetate (100 mL) and water (50 mL) were added to the mixture and the solid was collected by filtration to afford 2-(2-chloroquinazolin-4-yl)acetamide (14.4 g, 54% yield).
3. 1-Methylpiperazine (34 g, 339 mmol, 5.0 eq.) was added to a solution of N-methylpyrrolidone (NMP, 250 mL) of 2-(2-chloroquinazolin-4-yl)acetamide (14.4 g, 65 mmol, 1.0 eq.), and stirred for 30 minutes at 50 °C. The mixture was then cooled to room temperature. After cooling to room temperature, ethyl acetate (100 mL) was added and the suspension was filtered to afford 2-(2-(4-methylpiperazin-1-yl)quinazolin-4-yl)acetamide (10.5 g, 55% yield).
4. Potassium tert-butoxide (t-BuOK, 215 mL, 121 mmol, 3.0 eq.) was added to an anhydrous THF (250) solution of 2-(2-(4-methylpiperazin-1-yl)quinazolin-4-yl)acetamide (10.5 g, 36.8 mmol, 1.0 eq.) and Intermediate 2 (10.5 g, 40.5 mmol, 1.1 eq.) at room temperature. mL) solution and stirred for about 30 minutes. The reaction mixture was quenched with water, extracted with ethyl acetate, the organic phase was washed with saturated brine, dried over anhydrous sodium sulfate and concentrated. Purification by silica gel column chromatography afforded methyl ester of Intermediate 8 (11 g, 60% yield). |
[References]
[1] Journal of Medicinal Chemistry, 2009, vol. 52, # 20, p. 6193 - 6196 [2] Journal of Medicinal Chemistry, 2011, vol. 54, # 17, p. 6028 - 6039 [3] Patent: WO2013/4709, 2013, A1. Location in patent: Page/Page column 54-55 [4] Patent: US2003/69424, 2003, A1 |