Hydrochloric Acid → 2-(5-fluoro-2H-benzo[d][1,2,3]triazol-2-yl)-6-(hydroxymethyl)-4-methoxyphenol

Participants

Reaction Conditions

Reaction Steps

In a 500 ml round bottom flask equipped with a magnetic stirrer, liquid addition funnel, powder addition funnel, and nitrogen inlet was added 2-((4-fluoro-2-nitrophenyl)diazenyl)-6-(hydroxymethyl)-4-methoxyphenol from Example 5 part I and 200 ml ethanol. NaOH (21.7 g, 542 mmol) pellets (97+%, A.C.S. reagent, Aldrich) were dissolved in 100 ml deionized water and approximately one-fourth of the solution was added dropwise to the reaction mixture. The mixture was subsequently heated to 80° C. and 29.3 g (271 mmol) formamidinesulfinic acid (Aldrich) and the remaining sodium hydroxide solution were concurrently added to the reaction mixture over 30 minutes. The mixture was stirred at 80° C. for 3 hours and the contents were then poured into 3 L deionized water and acidified to pH 4 using 1N HCl. The solid was collected by filtration, suspended in 300 ml methanol, and stirred for 30 minutes while cooling to below −20° C. The solid was collected by filtration and then suspended in 300 ml ethanol, cooled again to below −20° C., filtered, and then dried to afford 7.8 g (30%) of a yellow solid, which was used in the next esterification step.

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