1,1,1-Trifluoropropan-2-yl carbonochloridate → 1,1,1-Trifluoropropan-2-yl 4-(4-(4-(methylsulfonyl)phenylamino)-6H-pyrimido[5,4-b][1,4]oxazin-8(7H)-yl)piperidine-1-carboxylate

Participants

Reaction Steps

To a suspension of N-(2-fluoro-4-(methylsulfonyl)phenyl)-8-(piperidin-4-yl)-7,8-dihydro-6H-pyrimido[5,4-b][1,4]oxazin-4-amine hydrochloric acid salt from Example 8A (35.5 mg, 0.08 mmol) in CH2Cl2 (1.5 mL) was added DIEP (70 μL, 0.40 mmol, Aldrich) followed by addition of 1,1,1-trifluoropropan-2-yl chloroformate (⅓ of the material from Step A, 0.33 mmol) in CH2Cl2 (0.5 mL). The reaction mixture was stirred for 30 min and then evaporated under the reduced pressure to yield the crude product which was purified by preparative HPLC (C18 column; 10-100% acetonitrile in water containing 0.05% trifluoroacetic acid) to give the desired product (33.9 mg, off-white solid, 51%) upon lyophilization. 1H NMR (500 MHz, CDCl3, 50° C.). δ 8.42 (t, J=8.25 Hz, 1H), 8.31 (brs, 1H), 8.14 (s, 1H), 7.59-7.78 (m, 2H), 5.18-5.34 (m, 1H), 4.78-4.93 (m, 1H), 4.22-4.41 (m, 4H), 3.47-3.55 (m, 2H), 3.04 (s, 3H), 2.88-3.07 (m, 2H), 1.79 (m, 2H), 1.60-1.75 (m, 2H), 1.42 (d, J=6.60 Hz, 3H)). LRMS (ESI) 548 (M+H)+.

Provenance & Evidence