Yield:22693-51-2 76%

Reaction Conditions:

with ammonium acetate at 90; for 6 h;

Steps:

10 g (0.069 mol) of 3-indolecarboxyaldehyde was placed In a round bottom flask together with 40 ml of nitroethane and 1.77 g of ammonium acetate. Reaction mixture was heated at 90°C for 6 hours, after cooling to room temperature the solvent was evaporated under reduced pressure. Product was crystallized from ethanol. A yellow solid was obtained (10.63 g, 76%). The obtained product was dissolved in anhydrous tetrahydrofuran (100 ml) and was added dropwise to a solution of 12.08 g of lithium aluminum hydride in 100 ml THF. Reaction mixture was heated at reflux for 10 hours, after cooling to room temperature water (12 ml), then 15% NaOH (12 ml) and water (36 ml) were added successively. The precipitate was filtered and washed with THF (200 ml) and THF:MeOH 1:1 (100 ml). The combined washes were evaporated under reduced pressure, then water was added (200 ml), and the mixture was acidified with acetic acid to pH = 4. The solution was extracted with dichloromethane (2x100 ml) and then was basified to pH = 12 and again extracted with dichloromethane (3x 100 ml). The extracts from basic solution were washed with brine, dried over anhydrous magnesium sulfate and evaporated under reduced pressure. Product was used without further purification. A light brown oil was obtained (6.48 g, 70%). LC-MS [M+1] = 175.11 (175.12 calcd).

References:

Staroń, Jakub;Kurczab, Rafa?;Warszycki, Dawid;Sata?a, Grzegorz;Krawczyk, Martyna;Bugno, Ryszard;Lenda, Tomasz;Popik, Piotr;Hogendorf, Adam S.;Hogendorf, Agata;Dubiel, Krzysztof;Mat?oka, Miko?aj;Moszczyński-P?tkowski, Rafa?;Pieczykolan, Jerzy;Wieczorek, Maciej;Zajdel, Pawe?;Bojarski, Andrzej J. [European Journal of Medicinal Chemistry,2020,vol. 185,art. no. 111857] Location in patent:supporting information