[I:1][C:2]1[CH:3]=[N:4][NH:5][CH:6]=1.C1(C)C=CC(S(O[CH2:17][C@H:18]2[CH2:22][O:21][C:20]([CH3:24])([CH3:23])[O:19]2)(=O)=O)=CC=1.C([O-])([O-])=O.[Cs+].[Cs+].CN(C=O)C>>[CH3:23][C:20]1([CH3:24])[O:19][C@@H:18]([CH2:17][N:4]2[CH:3]=[C:2]([I:1])[CH:6]=[N:5]2)[CH2:22][O:21]1A mixture of 4-iodopyrazole (1.00 g, 5.16 mmol), (R)-(−)-(2,2-Dimethyl-1,3-dioxolan-4-yl)methyl p-toluenesulfonate (1.624 g, 5.671 mmol), Cs2CO3 (2.52 g, 7.73 mmol) and DMF (8 mL, 100 mmol) was heated to 100° C. for 2 h. The solution was extracted with EtOAc, and washed with water (2×). The organic layer was concentrated in vacuo and purified via column chromatography, eluting with 2-10% EtOAc/hexanes. The fractions containing the pure product were concentrated in vacuo to afford the title compound as a white solid. MS (ES+): m/z=309.00 (100) [MH+]. HPLC: tR=1.32 min (polar—3 min, UPLC-ACQUITY).
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