Hydrochloric Acid → 2-((4-Fluoro-2-nitrophenyl)diazenyl)-6-(hydroxymethyl)-4-methoxyphenol

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

In a 500 ml round bottom flask equipped with a magnetic stirrer was added 25.1 g (161 mmol) 4-fluoro-2-nitroaniline (Aldrich), HCl(aq) (J.T. Baker), 100 ml deionized water, and 100 ml absolute ethanol. The suspension was cooled to 0° C. 11.8 g (171 mmol) Sodium nitrite (Sigma-Aldrich) in 50 ml water was added dropwise over 60 minutes while keeping the reaction mixture at 0° C. The reaction mixture was stirred for an additional 1 hour. 420 mg sulfamic acid (Aldrich) was added and the reaction mixture was stirred for an additional 30 minutes and then filtered. In a 1 liter round bottom flask was combined 32.5 g (176 mmol) (2-hydroxy-5-methoxy-1,3-phenylene)dimethanol, 200 ml deionized water, and 200 ml ethanol. 32.3 g (807 mmol) NaOH (Aldrich) was dissolved in 100 ml water and approximately one-fourth of this was added to the solution containing the phenol derivative at 0° C. The diazonium salt solution and remaining sodium hydroxide solution were added dropwise to the reaction mixture at 0° C. over a 1 hour period and then allowed to stir for an additional 1 hour at 0° C. and 3 hours at ambient temperature. The reaction mixture was poured into 3 liters water and the pH was adjusted to 4 using 1N HCl. The solid was collected by filtration, washed with several liters of water, and vacuum dried (0.1 mm Hg) at 55° C. for 72 hours using P2O5 as drying agent to afford 29.9 g (68%) of a dark solid which was used in the next step without further purification.

Herkunft & Nachweise