N#N.[CH3:3][C:4]1([C:9]2[N:10]=[C:11]([CH2:14][OH:15])[S:12][CH:13]=2)[O:8][CH2:7][CH2:6][O:5]1.CCN(CC)CC.[S:23](Cl)([CH3:26])(=[O:25])=[O:24]>C(Cl)Cl.CN(C1C=CN=CC=1)C>[CH3:3][C:4]1([C:9]2[N:10]=[C:11]([CH2:14][O:15][S:23]([CH3:26])(=[O:25])=[O:24])[S:12][CH:13]=2)[O:8][CH2:7][CH2:6][O:5]1
In a flame dried round-bottomed flask equipped with a magnetic stir bar and under inert atmosphere (N2), a solution of [4-(2-methyl-[1,3]dioxolan-2-yl)-thiazol-2-yl]-methanol (745 mg, 3.70 mmol) in dry CH2Cl2 (5 mL) was treated at 0° C. with Et3N (0.67 mL, 4.79 mmol) followed by DMAP (46 mg, 0.37 mmol) and Ms-Cl (0.37 mL, 4.67 mmol). After stirring at 0° C. for 1 h30, the reaction was quenched with water (5 mL). The org. layer was dried over MgSO4, filtered, and the solvents were removed under reduced pressure to give crude methanesulfonic acid 4-(2-methyl-[1,3]dioxolan-2-yl)-thiazol-2-ylmethyl ester as a yellow oil. The crude material (580 mg) was dissolved in acetone (12 mL) under inert atmosphere (N2). 4-Nitro-1H-pyrazole (264 mg, 2.08 mmol) was added followed by K2CO3 (1.45 g, 10.38 mmol) and TBA bromide (134 mg, 0.41 mmol). The reaction mixture was stirred overnight at rt and concentrated to dryness. The residue was partitioned between water (10 mL) and EA (20 mL). The layers were separated and the aq. layer extracted with EA (2×30 mL). The combined org. extracts were dried over MgSO4, filtered, and the solvent removed under reduced pressure. Purification of the residue by FC (10:1 to 2:1 hept-EA) gave the title compound as a yellow oil. TLC: rf (1:2 hept-EA)=0.41. LC-MS-conditions 02: tR=0.86 min, [M+H]+=297.35.
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