Reaction Steps
A mixture of (S)-ethyl 2-(7-(4-(allyloxy)-4-methylpiperidin-1-yl)-2-(azidomethyl)-5-methylpyrazolo[1,5-a]pyrimidin-6-yl)-2-(tert-butoxy)acetate (0.206 g, 0.412 mmol) and Ph3P (0.162 g, 0.618 mmol) in 9:1 THF/H2O) (15 mL) was refluxed for 2 h. Then, cooled, diluted with Et2O (50 mL) and extracted with 0.1M HCl (3×10 mL). The organic layer discarded and the combined aqueous. layers neutralized with sat Na2CO3 and extracted with CH2Cl2 (3×10 mL). The combined CH2Cl2 layers dried (MgSO4), filtered and concentrated to give (S)-ethyl 2-(7-(4-(allyloxy)-4-methylpiperidin-1-yl)-2-(aminomethyl)-5-methylpyrazolo[1,5-a]pyrimidin-6-yl)-2-(tert-butoxy)acetate (0.193 g, 0.408 mmol, 99% yield) as pale yellow paste which was used in the next step without purification. To a stirred solution of (S)-ethyl 2-(7-(4-(allyloxy)-4-methylpiperidin-1-yl)-2-(aminomethyl)-5-methylpyrazolo[1,5-a]pyrimidin-6-yl)-2-(tert-butoxy)acetate (0.195 g, 0.412 mmol), 2-(allyl(4-fluoro-3-methylbenzyl)amino)-2-oxoacetic acid (0.207 g, 0.824 mmol) and DIEA (0.288 ml, 1.648 mmol) in DMF (5 mL) was added HATU (0.470 g, 1.236 mmol) at rt. After 17 h, the reaction mixture was taken up in Et2O (100 mL), washed with 1M HCl (5 mL), water (3×10 mL), brine (10 mL), dried (MgSO4), filtered, concentrated and purified by prep-HPLC to afford (S)-ethyl 2-(2-((2-(allyl(4-fluoro-3-methylbenzyl)amino)-2-oxoacetamido)methyl)-7-(4-(allyloxy)-4-methylpiperidin-1-yl)-5-methylpyrazolo[1,5-a]pyrimidin-6-yl)-2-(tert-butoxy)acetate (0.1145 g, 0.162 mmol, 39.3% yield) as yellow paste. 1H NMR (400 MHz, CDCl3) δ 7.92 (d, J=14.8 Hz, 1H), 7.03-7.16 (m, 2H), 6.91-6.99 (m, 1H), 6.42 (s, 1H), 5.69-6.07 (m, 3H), 5.43 (d, J=17.3 Hz, 1H), 5.11-5.26 (m, 3H), 5.00 (s, 1H), 4.68 (t, J=5.4 Hz, 2H), 4.54 (s, 1H), 4.38 (d, J=5.8 Hz, 1H), 4.12-4.27 (m, 3H), 3.95-4.05 (m, 3H), 3.92 (d, J=6.0 Hz, 1H), 2.59 (s, 3H), 2.26 (d, J=1.76 Hz, 3H), 1.81-2.03 (m, 3H), 1.72 (td, J=2.6, 7.0 Hz, 1H), 1.34 (s, 3H), 1.20-1.25 (m, 12H). LCMS (M+H)=707.7.
