To a solution of (2S)-methyl 2-(7-(4-allyl-5-chloro-3,4-dihydro-2H-benzo[b][1,4]oxazin-6-yl)-2-(3′-hydroxy-[1,1′-biphenyl]-3-yl)-5-methylpyrazolo[1,5-a]pyrimidin-6-yl)-2-(tert-butoxy)acetate (90 mg, 0.138 mmol) in DMF (2 mL) was added K2CO3 (38.1 mg, 0.276 mmol) followed by 3-bromoprop-1-ene (0.017 mL, 0.207 mmol) and the resulting mixture was heated at 50° C. for 16 h. After cooling to room temperature, water was added and the mixture was extracted with ether (50 mL), washed with brine, dried (Na2SO4), filtered and concentrated. Crude was then purified by biotage (5-30% EtOAc/hexane) to afford (2S)-methyl 2-(7-(4-allyl-5-chloro-3,4-dihydro-2H-benzo[b][1,4]oxazin-6-yl)-2-(3′-(allyloxy)-[1,1′-biphenyl]-3-yl)-5-methylpyrazolo[1,5-a]pyrimidin-6-yl)-2-(tert-butoxy)acetate (40 mg, 0.058 mmol, 41.9% yield) as white solid. 28 mg of starting material was also recovered. 1H NMR (500 MHz, CDCl3) δ: 8.05 (t, J=1.6 Hz, 1H), 7.84 (dt, J=7.7, 1.4 Hz, 1H), 7.57-7.53 (m, 1H), 7.45 (t, J=7.6 Hz, 1H), 7.37 (t, J=7.9 Hz, 1H), 7.23-7.20 (m, 1H), 7.19-7.16 (m, 1H), 7.03-6.97 (m, 2H), 6.96-6.92 (m, 2H), 6.17-6.00 (m, 2H), 5.50-5.44 (m, 1H), 5.39-5.29 (m, 3H), 5.25 (dd, J=10.2, 1.6 Hz, 1H), 5.09 (s, 1H), 4.62 (dt, J=5.3, 1.4 Hz, 2H), 4.27 (t, J=4.4 Hz, 2H), 3.67 (s, 3H), 3.27-3.17 (m, 2H), 2.86 (s, 3H), 1.19 (s, 9H). LCMS (M+H)=693.4.
