N#N.[CH3:3][C:4]1([C:9]2[N:10]=[C:11]([CH2:14]OS(C)(=O)=O)[S:12][CH:13]=2)[O:8][CH2:7][CH2:6][O:5]1.[N+:20]([C:23]1[NH:27][N:26]=[CH:25][CH:24]=1)([O-:22])=[O:21].C([O-])([O-])=O.[K+].[K+].[Br-]>CC(C)=O.CC(=O)OCC.O>[CH3:3][C:4]1([C:9]2[N:10]=[C:11]([CH2:14][N:26]3[CH:25]=[CH:24][C:23]([N+:20]([O-:22])=[O:21])=[N:27]3)[S:12][CH:13]=2)[O:5][CH2:6][CH2:7][O:8]1In a flame dried round-bottomed flask equipped with a magnetic stir bar and under inert atmosphere (N2), a solution of methanesulfonic acid 4-(2-methyl-[1,3]dioxolan-2-yl)-thiazol-2-ylmethyl ester (320 mg, 1.15 mmol) in acetone (6.0 mL) was added to a solution of 5-nitro-1H-pyrazole (136 mg, 1.20 mmol) in acetone (6.0 mL). K2CO3 (800 mg, 5.73 mmol) followed by TBA bromide (741 mg, 0.23 mmol) were added and the reaction mixture was stirred at rt overnight. 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 MgSO4, filtered, and the solvents were removed under reduced pressure. Purification of the residue by FC (2:1 hept-EA) gave the title compound as a yellow oil. TLC: rf (2:1 hept-EA)=0.10. LC-MS-conditions 01: tR=0.81 min, [M+H]+=296.90.
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