N#N.[CH3:3][C:4]1([C:9]2[CH:10]=[C:11]([CH:18]=[CH:19][CH:20]=2)[CH2:12]OS(C)(=O)=O)[O:8][CH2:7][CH2:6][O:5]1.[N+:21]([C:24]1[CH:25]=[N:26][NH:27][CH:28]=1)([O-:23])=[O:22].C([O-])([O-])=O.[K+].[K+].[Br-]>CC(C)=O>[CH3:3][C:4]1([C:9]2[CH:10]=[C:11]([CH:18]=[CH:19][CH:20]=2)[CH2:12][N:26]2[CH:25]=[C:24]([N+:21]([O-:23])=[O:22])[CH:28]=[N:27]2)[O:8][CH2:7][CH2:6][O:5]1In a flame dried round-bottomed flask equipped with a magnetic stir bar and under inert atmosphere (N2), a solution of methanesulfonic acid 3-(2-methyl-[1,3]dioxolan-2-yl)-benzyl ester (220 mg, 0.81 mmol) and 4-nitro-1H-pyrazole (103 mg, 0.81 mmol) in acetone (8.0 mL) was treated with K2CO3 (564 mg, 4.04 mmol) followed by TBA bromide (48 mg, 0.15 mmol). The reaction mixture was stirred at rt for 16 h. The solvent was removed under reduced pressure. Water (10 mL) and EA (10 mL) were added. The aq. layer was extracted with EA (10 mL) and the combined org. extracts were dried over Na2SO4, filtered, and the solvents were removed under reduced pressure. Purification of the residue by FC (80:20 hept-EA) gave the title compound as a pale yellow solid. TLC: rf (50:50 hept-EA)=0.5. LC-MS-conditions 02: tR=0.97 min.
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