399-51-9, 6-Fluoro-1H-indole is a indole-building-block compound, ?involved in a variety of chemical synthesis. Rlated chemical reaction is continuously updated
Synthesis of the Compound of Formula IIDetailed syntheses of the compound of Formula II from commercially available 6-fluoroindole are provided below. Scheme II uses diethoxymethane and dimethylamine to generate the ?iminium ion species?. An alternative procedure using formaldehyde in place of diethoxymethane is also provided below. Synthetic Procedure:Preparation of formaldehyde was carried out in reactor A. The synthesis of the compound of Formula II was carried out in reactor B. Precipitation of the final product was carried out in reactor C.Procedure:To reactor A were charged diethoxymethane (65 ml/54 g), water (50 ml) and formic acid (39 ml/47 g). The mixture was heated to about 80 C./reflux for about 2 hours and then cooled to about 20 C. To reactor B were charged 6-fluoroindole (50 g) and 80% acetic acid (66 ml/70 g, 2.5 eq. to 6-fluoroindole). The suspension was cooled to 2-5 C. 40% Dimethylamine (aq) (103 ml/92 g, 2.2 eq. to 6-fluoroindole) was added drop-wise to reactor B keeping the temperature below about 15 C. The reaction mixture was stirred for about 20 minutes and at the same time the temperature was adjusted to 2-4 C.The mixture from reactor A (DEM, water, formic acid, formaldehyde and ethanol at about 20 C.) was added drop-wise to reactor B while keeping the temperature at 2-8 C. The reaction mixture was stirred for additional 10 minutes at 2-8 C. The reaction mixture was slowly warmed to about 40 C. over a 1 hour period. The reaction mixture was stirred at about 40 C. for an additional 1 hour. The reaction mixture was cooled to about 20 C.To reactor C was charged 3M NaOH (800 ml, 1.24 eq. to the acetic acid+the formic acid) and the solution was cooled to about 10 C. The reaction mixture from reactor B was added drop-wise to the NaOH solution in reactor C while keeping the temperature at 10-15 C. (pH>14). The suspension was stirred for 40 minutes at 5-20 C. (pH>14). The product was collected by filtration and the filter-cake was washed twice with water (2×250 ml). The product was dried at about 60 C. under vacuum for 16 hours. Yield: 95%. Purity by HPLC (280 nm): 98 area %., 399-51-9
399-51-9 6-Fluoro-1H-indole 351278, aindole-building-block compound, is more and more widely used in various fields.
Reference：
Patent; H. LUNDBECK A/S; US2011/152539; (2011); A1;,
Indole alkaloid derivatives as building blocks of natural products from?Bacillus thuringiensis?and?Bacillus velezensis?and their antibacterial and antifungal activity study
Preparation of Indole Containing Building Blocks for the Regiospecific Construction of Indole Appended Pyrazoles and Pyrroles