Reaction Steps
A mixture of 3-[7-((E)-2-ethoxy-vinyl)-4-methyl-3-oxo-2,3,4,10-tetrahydro-9-oxa-1,2,4a-triaza-phenanthren-6-ylamino]-3-methyl-azetidine-1-carboxylic acid tert-butyl ester (prepared from tert-butyl 3-((8-bromo-1-methyl-2-oxo-1,2,3,5-tetrahydrobenzo[5,6][1,4]oxazino[3,4-c][1,2,4]triazin-9-yl)amino)-3-methylazetidine-1-carboxylate (Preparation #18) using the similar procedure detailed in Example #148, Step H) 0.65 g, 1.378 mmol) in TFA (4 mL) was stirred at ambient temperature for 20 min. Triethylsilane (4.8 g, 41.4 mmol) was added and the reaction mixture was stirred for 24 h. The solvent was removed in vacuo to give 1-methyl-10-(3-methylazetidin-3-yl)-5,8,9,10-tetrahydro-1H-[1,2,4]triazino[4′,3′:4,5][1,4]oxazino[2,3-f]indol-2(3H)-one 2,2,2-trifluoroacetate (0.65 g, crude). Prep-HPLC (Table 3, Method 29) purification of 20 mg of crude product gave 1-methyl-10-(3-methyl-azetidin-3-yl)-3,5,9,10-tetrahydro-8H-6-oxa-3,4,10,11b-tetraaza-cyclopenta[b]phenanthren-2-one 2,2,2-trifluoroacetate (0.011 g). 1H NMR (400 MHz, DMSO-d6): δ 10.69 (s, 1H), 9.15 (s, 1H), 8.91 (brs, 1H), 6.80 (s, 1H), 5.95 (s, 1H), 4.98 (m, 1H), 4.45 (s, 2H), 4.11 (m, 4H), 3.25 (m, 1H), 2.84 (m, 2H), 1.40 (s, 3H), 1.20 (m, 3H). LC/MS (Table 1, Method 4) Rt=0.799 min; MS m/z: 328 [M+H]+.
