[N+:1]([C:4]1[CH:11]=[CH:10][C:7]([CH:8]=[O:9])=[C:6]([O:12][CH3:13])[CH:5]=1)([O-:3])=[O:2].CC1C=CC(S([CH2:24][N+:25]#[C-:26])(=O)=O)=CC=1.C([O-])([O-])=O.[K+].[K+].CO>O>[N+:1]([C:4]1[CH:11]=[CH:10][C:7]([C:8]2[O:9][CH:26]=[N:25][CH:24]=2)=[C:6]([O:12][CH3:13])[CH:5]=1)([O-:3])=[O:2]To a 5 L three necked round bottom flask equipped with a condenser and a mechanical stirrer was placed 1B (146.3 g, 0.8076 mol), TOSMIC (157.7 g, 0.8077 mol), K2CO3 (116.6 g, 0.8075 mol) and MeOH (2.5 L). The mixture was heated to reflux under N2 and stirred for 3 hours. Water (1.25 L) was added drop-wise while maintaining the pot temperature between 59-69° C. The resulting slurry was cooled to room temperature, and then to 5° C. with an ice-water bath. After stirring for 30 minutes at 5° C., the slurry was filtered. The resulting cake was washed with water (3×400 mL) and dried in a vacuum oven at 45° C. for 20 hours to give 5-(4-nitro-2-methoxyphenyl)oxazole (IC, 148.5 g, 84%) as a yellow-reddish solid. 1H NMR (CDCl3) d 8.02 (s, 1H), 7.97 (d, J=2 Hz, 1H), 7.95 (d, J=2 Hz, 1H), 7.86 (s, 1H), 7.78 (s, 1H), 4.11 (s, 3H).
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