[NH2:1][C:2]1[C:12]([NH2:13])=[CH:11][CH:10]=[C:9]([F:14])[C:3]=1[C:4]([O:6][CH2:7][CH3:8])=[O:5].[N:15]([O-])=O.[Na+]>O.C(O)(=O)C>[F:14][C:9]1[CH:10]=[CH:11][C:12]2[N:13]=[N:15][NH:1][C:2]=2[C:3]=1[C:4]([O:6][CH2:7][CH3:8])=[O:5]ethyl 2,3-diamino-6-fluorobenzoate (1.00 g, 5.04 mmole) in 50 ml of water and 10 ml acetic acid was cooled to −10° C. To this solution was added dropwise sodium nitrite (348 mg, 5.04 mmole) in 30 ml of water. After the addition the reaction was warmed to 0° C. for 30 min, then to room temperature for 1 hr, and finally 50° C. for 1 hr. The reaction was filtered after stirring over night and washed with water. The dark brownish purple solid was dissolved in ethylacetate dried over magnesium sulfate and evaporated to afford ethyl 6-fluoro-1H-1,2,3-benzotriazole-7-carboxylate (920 mg, 87% yield) 1H NMR (400 MHz, METHANOL-D4) δ ppm 1.3 (t, J=7.1 Hz, 3H) 4.4 (q, J=7.0 Hz, 2H) 7.2 (dd, J=11.2, 9.0 Hz, 1H) 8.1 (dd, J=9.1, 4.1 Hz, 1H).
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