A Selenium-Based Ionic Liquid as a Recyclable Solvent for the Catalyst-Free Synthesis of 3-Selenylindoles

Abstract

The ionic liquid 1-butyl-3-methylimidazolium methylselenite, [bmim][SeO2(OCH3)], was successfully used as solvent in the catalyst-free preparation of 3-arylselenylindoles by the reaction of indole with ArSeCl at room temperature. The products were obtained selectively in good yields without the need of any additive and the solvent was easily reused for several cycles with good results.

Metal- and photocatalyst-free synthesis of 3-selenylindoles and asymmetric diarylselenides promoted by visible light

“…The heterocycle 4-phenylthiazole-2-amine was synthetized from 2bromoacetophenone and thiourea in ethanol. The reaction products were isolated by ash column chromatography (silica gel, eluting with 8 : 2 hexanes/ethyl acetate) from the reaction mixture and characterized by 1 H, 13 C and 77 Se NMR and mass spectrometry. 1 H, 13 C, 19 F and 77 Se NMR spectra were recorded at 400, 101, 377 and 76 MHz respectively on a Bruker 400 spectrometer with CDCl 3 as a solvent.…”

“…Transition metals catalysis using organic diselenides 11 or elemental selenium as a selenium source is also well described. 12 The most common examples include the reaction between indoles and selenium electrophilic species, 13 where the latter can be in situ generated from the corresponding diselenides using an oxidant in stoichiometric 14 or catalytic 15 amounts. On the other hand, procedures using bases such as K 2 CO 3 , 16 Cs 2 CO 3 17 or t-BuOK 18 assisting the formation of 3selenylindoles are also reported.…”

Ultrasound‐Assisted Synthesis and Antioxidant Activity of 3‐Selanyl‐1 H‐indole and 3‐Selanylimidazo[1,2‐a]pyridine Derivatives

“…: 136–138 °C, lit. : 118–121 °C; Yield: 0.180 g (94 %); 1 H NMR (CDCl 3 , 300 MHz): δ =8.47 (br s, 1 H), 7.73–7.72 (m, 1 H), 7.45 (d, J= 2.6 Hz, 1 H), 7.33 (dd, J= 8.6, 1.8 Hz, 1 H), 7.27 (d, J= 8.6 Hz, 1 H), 7.14–7.05 ppm (m, 4 H); 13 C NMR (CDCl 3 , 75 MHz): δ =135.0, 132.4, 131.8, 131.5, 129.9, 129.8, 129.1, 126.0, 122.7, 114.4, 112.9, 97.5 ppm; MS m / z (rel. int.…”

“…: 116–119 °C, lit. : 116–119 °C; Yield: 0.138 g (86 %); 1 H NMR (CDCl 3 , 300 MHz): δ =7.57 (dt, J= 7.8, 1.0 Hz, 1 H), 7.35 (dt, J= 8.2, 1.0 Hz, 1 H), 7.31–7.24 (m, 2 H), 7.21–7.02 (m, 5 H), 3.80 ppm (s, 3 H); 13 C NMR (CDCl 3 , 75 MHz): δ =137.4, 135.6, 132.4, 131.4, 130.3, 129.8, 128.9, 122.5, 120.5, 120.2, 109.6, 95.5, 33.0 ppm; MS m / z (rel. int.…”

Selective synthesis of 3‐Selanylindoles from Indoles and Diselenides using IK/mCPBA system

“…More recently, Braga's group demonstrated a green procedure for affording 3‐selanylindoles, they fount that only adding a catalytic amount of K 2 CO 3 in ethanol, the reaction of indoles with diselenides proceeded efficiently and gave the products in good yields by a radical pathway . The similar protocols in ionic liquids had been also investigated before . These above methods, despite being versatile process, the synthesis of 3‐selenylindoles and study on their potential bioactivity have not been extensively explored compared with the analogous 3‐thioindoles.…”