Triethyl phosphite → 8-Methoxy-1,6-dihydrocyclopenta[c]carbazol-3(2H)-one

Participants

Reaction Conditions

Reaction Steps

Biphenyl 35 obtained (5.59 g) was divided into five portions (1.11 g each); then P(OEt)3 (per 7 mL) was added to each portion. The resulting mixture was subjected to argon blow in a flask, heated up to 90° C., kept at this temperature for 3 days, and cooled down. Carbazole was precipitated. Then the reaction mixture was diluted with ether; the precipitate was filtered off and washed with CH2Cl2. If the initial biphenyl remained in the filtrate (TLC monitoring, eluent: hexane-ethyl acetate, 1:1), this filtrate was evaporated and P(OEt)3 (per 1 mL into each flask) was added. The mixture was subjected to repeated cyclization for a day. The procedure repeated until the precipitation ceased and TLC data showed the absence of the initial biphenyl. Total yield of carbazole 36: 2.16 g.

Provenance & Evidence