[Cl:1][C:2]1[CH:3]=[C:4]([CH:9]=[CH:10][C:11]=1[C:12]1[C:35](=[O:36])[N:34]([CH2:37][CH3:38])[C:15]2[N:16]=[C:17]([NH:20][C:21]3[CH:26]=[CH:25][C:24]([N:27]4[CH2:32][CH2:31][N:30]([CH3:33])[CH2:29][CH2:28]4)=[CH:23][CH:22]=3)[N:18]=[CH:19][C:14]=2[CH:13]=1)[C:5]([NH:7][NH2:8])=[O:6].F[C:40](F)(F)C(O)=O>C(OCC)(OCC)OCC>[Cl:1][C:2]1[CH:3]=[C:4]([C:5]2[O:6][CH:40]=[N:8][N:7]=2)[CH:9]=[CH:10][C:11]=1[C:12]1[C:35](=[O:36])[N:34]([CH2:37][CH3:38])[C:15]2[N:16]=[C:17]([NH:20][C:21]3[CH:22]=[CH:23][C:24]([N:27]4[CH2:28][CH2:29][N:30]([CH3:33])[CH2:31][CH2:32]4)=[CH:25][CH:26]=3)[N:18]=[CH:19][C:14]=2[CH:13]=13-Chloro-4-{8-ethyl-2-[4-(4-methyl-piperazin-1-yl)-phenylamino]-7-oxo-7,8-dihydro-pyrido[2,3-d]pyrimidin-6-yl}benzoic acid hydrazide (7, 30 mg, 0.06 mmol) was suspended in triethyl orthoformate (5 mL) to which was added trifluoroacetic acid (1 mL). The resulting reaction mixture was heated at 130° C. for 2 h. The volatiles were removed and the residue was taken up in dichloromethane (1×20 mL) and washed with 10% sodium hydroxide solution (2×10 mL). The organic layer was dried over sodium sulfate, filtered and evaporated. The residue was purified by column chromatography using dichloromethane:methanol (95:5). The title compound (18 mg, 0.03 mmol, 50%) was obtained as a yellow solid. ESMS m/z 543 (M+H)+; 1H NMR (400 MHz, CDCl3) δ ppm 8.57 (s, 1H) 8.50 (s, 1H) 8.21 (d, J=1.5 Hz, 1H) 8.04 (dd, J=8.0, 1.5 Hz, 1H) 7.62 (s, 1H) 7.52-7.60 (m, 3H) 7.29 (br. s., 1H) 6.98 (d, J=9.0 Hz, 2H) 4.50 (q, J=6.8 Hz, 2H) 3.16-3.27 (m, 4H) 2.56-2.65 (m, 4H) 2.37 (s, 3H) 1.39 (d, J=6.8 Hz, 3H).
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