Chlorosuccinimide → 1-(Thiophen-3-yl)-1,3-dihydro-2H-indol-2-one

Participants

Reaction Steps

To a solution of 1-(3-thienyl)indole (9.14 g, 0.0459 M) in 350 ml of dry methylene chloride under a nitrogen atmosphere was added 6.44 g (0.0482 M) of N-chlorosuccinimide (NCS) at room temperature. The reaction was stirred at room temperature for 2 hours, then concentrated in vacuo. The resulting foamy residue was immediately dissolved in 190 ml of glacial acetic acid. The resulting mixture was heated to 70° C. followed by the addition of 49.5 ml of 85% H3PO4 and heating of the reaction mixture to reflux for one hour. The mixture was then cooled to room temperature, poured onto ice water, basified to pH ~11-12 with Na2CO3 and extracted with ethyl acetate (3×500 ml). The combined ethyl acetate extracts were washed with water, brine, dried (MgSO4), filtered and concentrated in vacuo leaving dark brown-black oil. Purification of the crude product on a silica gel column (elution with CH2Cl2, followed by elution with 90% CH2Cl2 --10% CH3OH) gave a total of 7.2 grams (72.8%) of brown crystalline solid; m.p. 62°-67° C. MS: M+= 215. IR(KBr) 5.9 μ(s) c=O. NMR(CDCl3)delta: 3.6 (s, 2H), 6.7-7.4 (m, 7H).

Provenance & Evidence