To a mixture of (R)-2-(4-(3-aminopyrrolidin-1-yl)-7-methylquinazolin-2-yl)-3-fluorophenol (200 mg, 0.59 mmol) and THF (6 mL) was added triethylamine (165 μL, 1.18 mmol) to form a clear solution. The mixture was cooled to −50° C. external temperature, and a 1:1 mixture of 2-methoxyethyl chloroformate (65 μL) and THF (65 μL) was added dropwise. After complete addition, the reaction was quenched with H2O and extracted with CH2Cl2. The combined organic extracts were dried over MgSO4, filtered, and concentrated. Purification via silica gel chromatography using 0-10% EtOAc in a 1:1 mixture of hexanes and CH2Cl2 gave (R)-2-methoxyethyl 1-(2-(2-fluoro-6-hydroxyphenyl)-7-methylquinazolin-4-yl)pyrrolidin-3-ylcarbamate (compound 1) (130 mg, 50%). 1H NMR (400 MHz, DMSO-d6) δ 8.19 (d, J=8.7 Hz, 1H), 7.71 (d, J=6.1 Hz, 1H), 7.58 (s, 1H), 7.33 (m, 2H), 6.76 (d, J=8.3 Hz, 1H), 6.69 (m, 1H), 4.22 (m, 1H), 4.04 (m, 5H), 3.84 (m, 1H), 3.48 (t, J=4.6 Hz, 2H), 3.23 (s, 3H), 2.52 (s, 3H), 2.20 (m, 1H), 2.02 (m, 1H) ppm. LC/MS: m/z 441.5 (M+H)+ at 2.10 min (10%-99% CH3CN (0.035% TFA)/H2O (0.05% TFA)).
