387-44-0, 7-Fluoroindole is a indole-building-block compound, ?involved in a variety of chemical synthesis. Rlated chemical reaction is continuously updated
7-Fluoro-5-(piperazin-1-yl)-1H-indole To a mixture of 7-fluoro-1H-indole (18.5 g, 0.14 mol), borane trimethylamine complex (80 g, 1.1 mol) and 1,4-dioxane (700 mL) was, over a periode of 15 min, added a 37% aqueous HCl (80 mL) solution. The resulting solution reached a maximum temperature of 40 C., and the solution was subsequent stirred at room temperature for another 16 h. The mixture was boiled under reflux for 1 h, 6 M aqueous HCl (500 mL) was added, and the resuting mixture was boiled under reflux for another 15 min. The solution was concentrated at atmospheric pressure and poured onto a mixture of ice and brine. The aqueous phase was made alkaline by the use of 25% aqueous ammonia and extracted with ethyl acetate. The combined organic phase was dried (MgSO4), filtered and concentrated in vacuo. The residue was dissolved in a mixture of triethylamine (38 mL, 0.27 mol) and tetrahydrofuran (350 mL) and cooled to 10 C. Acetyl Chloride (11.2 g, 0.14 mol) was added to the mixture, which thereafter was filtered and concentrated in vacuo. The residue was purified by flash chromatography (ethyl acetate/heptane 50:50) to give 1-(7-fluoro-2,3-dihydro-1H-indol-1-yl-ethanone (16.7 g, 0.09 mol), which was dissolved in acetic acid (250 mL). To this mixture was added 100% nitric acid (5.8 ml, 0.14 mol) over a period of 5 min, and the resulting mixture was stirred at room temperature for 2 h. The reaction was not run to completion, and an additional amount of 6 mL of 100% nitric acid was added. Another 6 mL of 100% nitric acid was added and the mixture was stirred at room temperature for 16 h. The mixture was poured onto a mixture of ice and brine. The aqueous phase was made alkaline by the use of 25% aqueous ammonia and extracted with ethyl acetate. The combined organic phase was washed with brine, dried (MgSO4), filtered and concentrated in vacuo. The residue was crystallised from a mixture of ethyl acetate and 2-propanol to give 1-(7-fluoro-5-nitro-2,3-dihydro-1H-indol-1-yl)-ethanone (15.9 g), which was dissolved in methanol (500 mL). To this solution was added ammonium formate (44.4 g, 0.7 mol) and palladium (5 wt %, dry basis) on activated carbon (4.0 g), and the mixture was boiled under reflux for 30 min. The mixture was cooled in an ice bath, filtered and concentrated in vacuo. The residue was dissolved in methanol (100 mL) and ethyl acetate (500 mL), and ammonium formate precipitated out of solution and was removed by filtration. The mother liquor was concentrated in vacuo, and the residue was purified by flash chromatography (ethyl acetate/heptane 65:35) to give 1-(5-amino-7-fluoro-2,3-dihydro-1H-indol-1-yl)-ethanone (13.1 g, >91%). The compound was dissolved in methanol (350 mL), 28% aqueous sodium hydroxide (100 mL) and water (100 mL), and the resulting mixture was boiled under reflux for 4 h. The reaction mixture was concentrated to a volume of about 200 mL, and brine (1 L) was added. The aqueous phase was extracted with a mixture of ethyl acetate and tetrahydrofuran. The combined organic phase was washed with brine, dried (MgSO4), filtered and concentrated in vacuo to give 7-fluoro-2,3-dihydro-1H-indol-5-ylamine (11.0 g, 96%). This compound was dissolved in p-xylene (500 mL), and palladium (5 wt %, dry basis) on activated carbon (7.5 g) was added. The resulting mixture was boiled under reflux by the use of a Dean/Stark trap for 1.5 h, cooled and filtered. The filter cake was washed with ethyl acetate and tetrahydrofuran, and the organic phases were combined and concentrated in vacuo. The residue was purified by flash chromatography (ethyl acetate/heptane 50:50) to give 7-fluoro-1H-indol-5-ylamine (3.3 g, 29%). A further batch of 7-fluoro-1H-indol-5-ylamine was prepared (0.2 g), and the combined batch was used in the following. A mixture of N-benzyliminodiacetic (5.9 g, 0.027 mol), 1,1′-carbonyldiimidazole (9.0 g, 0.056 mol) and tetrahydrofuran (175 mL) was boiled under reflux for 30 min. To this solution was added a solution of 7-fluoro-1H-indol-5-ylamine (3.47 g, 0.023 mol) in tetrahydrofuran (75 mL) over a period of 1 h. The resulting mixture was boiled under reflux for 3 h and concentrated in vacuo to 50 mL. This solution was purified by flash chromatography (ethyl acetate/heptane 80:20) to give 4-benzyl-1-(7-fluoro-1H-indol-5-yl)piperazine-2,6-dione (7.8 g, 95%), which was dissolved in tetrahydrofuran (75 mL) and subsequently added drop wise to a solution of alane in tetrahydrofuran over 60 min at 5-10 C. The resulting mixture was stirred at 7 C. for 30 min and then quenched by addition of water (6.5 mL), 15% aqueous sodium hydroxide (3.25 mL) and water (16 mL). MgSO4 was added to the mixture, which was filtered and concentrated in vacuo. The residue was purified by flash chromatography (ethyl acetate/heptane 50:50) to give 5-(4-benzylpiperazin-1-yl)-7-fluoro-1H-indole (4.9 g, 63%). The alane was prepared as described in the following: Lithium aluminium hydride (3.23 g, 0.085 mol) was suspended in tet…, 387-44-0
387-44-0 7-Fluoroindole 2774504, aindole-building-block compound, is more and more widely used in various fields.
Reference£º
Patent; Bang-Andersen, Benny; Larsen, Krestian; Mork, Niels; US2007/43058; (2007); 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